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Oracle SQL Tutorial 18 - How to Create Foreign Keys
 
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In this video we are going to be creating foreign keys. I highly recommend watching the previous video before you watch this one. Essentially, we are creating a very simple database for a system where we can create projects and add people to those projects. We started with the users table: --Delete the table if needed: --DROP TABLE users; CREATE TABLE users( user_id NUMBER, username VARCHAR2(50 CHAR) UNIQUE, CONSTRAINT users_pk PRIMARY KEY (user_id) ); Now we are going to create a table for projects with a column that is a foreign key to the username. We're going to want to make this match data types: CREATE TABLE projects( project_id NUMBER, project_name VARCHAR2(50 CHAR) UNIQUE, creator VARCHAR2(50 CHAR) ) Next, we need to add the column attributes we decided on last video: CREATE TABLE projects( project_id NUMBER, project_name VARCHAR2(50 CHAR) UNIQUE, creator VARCHAR2(50 CHAR) NOT NULL ) NOT NULL because we want every project to have a creator, but we are not labeling UNIQUE because that means we could only have a specific username once in the table. We want to allow a user to create multiple projects. We also need to add a primary key: CREATE TABLE projects( project_id NUMBER, project_name VARCHAR2(50 CHAR) UNIQUE, creator VARCHAR2(50 CHAR) NOT NULL, CONSTRAINT projects_pk PRIMARY KEY (username) ) Now, the question that remains is, how can I tell Oracle that I want the username to reference the username column of the other table? We have to make a foreign key constraint. As you've learned from the previous videos, there are about three ways to create constraints. You can do it inline at the column level, unnamed. You can do it at the column level, named, and you can do it at the Table level, named. Usually the table-level is preferred, but I will quickly remind you how to do all three again. CREATE TABLE projects( project_id NUMBER, project_name VARCHAR2(50 CHAR) UNIQUE, creator VARCHAR2(50 CHAR) NOT NULL REFERENCES users (username), CONSTRAINT projects_pk PRIMARY KEY (project_id) ) This works, but if we want to name it, we should do this: CREATE TABLE projects( project_id NUMBER, project_name VARCHAR2(50 CHAR) UNIQUE, creator VARCHAR2(50 CHAR) NOT NULL CONSTRAINT projects_users_fk REFERENCES users (username), CONSTRAINT projects_pk PRIMARY KEY (project_id) ) This works, but the preferred method is to do it at the table level: CREATE TABLE projects( project_id NUMBER, project_name VARCHAR2(50 CHAR) UNIQUE, creator VARCHAR2(50 CHAR) NOT NULL, CONSTRAINT projects_pk PRIMARY KEY (project_id), CONSTRAINT projects_users_fk FOREIGN KEY (creator) REFERENCES users (username) ) Great! So you've learned how to create a foreign key, now we can see it inside of Oracle SQL Developer. One important thing when it comes to foreign keys is what happens when have data in your database and you try to delete the parent row that a row in the child table references? In the next video we are going to configure that using ON DELETE. See you all then and if you enjoy this series, please do me a huge favor by liking the video and subscribing to my YouTube channel. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ HELP ME! http://www.patreon.com/calebcurry Subscribe to my newsletter: http://bit.ly/JoinCCNewsletter Donate!: http://bit.ly/DonateCTVM2. ~~~~~~~~~~~~~~~Additional Links~~~~~~~~~~~~~~~ More content: http://CalebCurry.com Facebook: http://www.facebook.com/CalebTheVideoMaker Google+: https://plus.google.com/+CalebTheVideoMaker2 Twitter: http://twitter.com/calebCurry Amazing Web Hosting - http://bit.ly/ccbluehost (The best web hosting for a cheap price!)
Views: 26731 Caleb Curry
Partitioning in Oracle Explained with Real project Examples : Introduction
 
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This Video series will explain partitioning and its use cases referencing real project examples from different domain. It will explain what when and why of partitioning in a simple but elaborate manner. This is the 1st video which explains why partitioning is required and what are the advantages we gain from it. The following videos will explain when should we do it and how.
Views: 32095 Tech Coach
How to get Parent Table, Reference Table, Foreign Key Constraint Name and Columns in SQL Server-P 71
 
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SQL Server / T-SQL Tutorial Scenario: You are working as SQL Server Developer, you are asked to provide the query that should return all the parent tables, reference tables, Foreign Key Constraints and Columns used in Foreign Key Constraint definition. Link to scripts used in SQL Server / TSQL Tutorial Video http://www.techbrothersit.com/2016/04/how-to-get-parent-table-reference-table.html Check out our website for Different SQL Server, MSBI tutorials and interview questions such as SQL Server Reporting Services(SSRS) Tutorial SQL Server Integration Services(SSIS) Tutorial SQL Server DBA Tutorial SQL Server / TSQL Tutorial ( Beginner to Advance) http://www.techbrothersit.com/
Views: 3575 TechBrothersIT
How to use lookup table in oracle Apex
 
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How to use lookup table in oracle Apex (Arabic)
Views: 292 ali saleh ali
Oracle SQL Tutorial 22 - Why Primary Keys Shouldn't Change
 
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In the last video I mentioned that with our database design it is important to make sure that nobody tries to update a user's username. What happens if they do? Nothing horrible, Oracle will just throw an error. That's not such a big deal, but if you are hoping to make some kind of application that allows someone to change their username, this is not the best set up. Why? If you look at the projects table, we have a foreign key that references the username. Let's assume for a moment that Oracle allows you to do anything with your data. That means that if a user updates their username, there will be projects created by users that don't exist. Or a user could change their name to the previous owner. To fix this problem, we would need something such as an ON UPDATE CASCADE command for our foreign key. That would mean that if the user updated their username, the columns that reference that username would also update to the new value. This exists in some database management systems, but this does not exist in Oracle at the time of this video. How do we get around this problem? I'm sure we could conjure up something to allow us to update the username, but the easiest solution is to reference the user_id instead of the username. That way, when the username is updated, nothing changes inside of the foreign key. As a general rule, primary keys should never change. Foreign keys CAN change, but they should not change because a primary key changed. So, if we did happen to use a username as a column, it would be frowned upon if the username had to change because the column it references changes. However, it would be acceptable to change the foreign key if we needed to point to a new entity in the users table. Even if a username is never intended to change, these complications bother a lot of people. You can mitigate these problems by only referencing surrogate keys in foreign keys. This has the downside though that when you retrieve the data, you are going to have to do more work to make the data readable. For example, we had a table that was called project_users. It is essentially a table that says what users are part of what projects. We could have the foreign keys reference the project's name and the user's username. Then when you could say SELECT * FROM project_users. The data would be completely readable without doing anything. If you switch to only referencing surrogate primary keys, you will have a bunch of random numbers that don't mean anything and will have to be joined with other tables…which is really super frustrating when later you have to join a thousand tables to read anything. Which side do you prefer? Pick a side. Choose wisely. I'll see you all in the next video ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ HELP ME! http://www.patreon.com/calebcurry Subscribe to my newsletter: http://bit.ly/JoinCCNewsletter Donate!: http://bit.ly/DonateCTVM2. ~~~~~~~~~~~~~~~Additional Links~~~~~~~~~~~~~~~ More content: http://CalebCurry.com Facebook: http://www.facebook.com/CalebTheVideoMaker Google+: https://plus.google.com/+CalebTheVideoMaker2 Twitter: http://twitter.com/calebCurry Amazing Web Hosting - http://bit.ly/ccbluehost (The best web hosting for a cheap price!)
Views: 6647 Caleb Curry
SQL Server 27 - How to Create FOREIGN KEY Constraints
 
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In the previous video we set up an entire table. The problem with this table is that the species column is just plain text. The problem with this is that there is a higher probability of incorrect data and if we have tons of animals in here there will be a lot of redundant information. The solution to this is to change this species to a foreign key to another table. Remember that when you create a foreign key it is a child to a parent. The thing you need to know is that the parent has to exist before the child so the child has something to reference. So let's create the parent table. CREATE TABLE Species( ID INT PRIMARY KEY IDENTITY, Species VARCHAR(50) NOT NULL UNIQUE, FriendlyName VARCHAR(50) NOT NULL //NOT UNIQUE because multiple rows could be same category (Ex: Bunny) ); Now, the friendly name will likely have redundant data, so maybe later we can add a table for animal categories or something, but let's not overwhelm ourselves quite yet. Maybe in a few videos. Now that we have created that table, we can recreate the table that references it. The first thing to know when creating a foreign key is that the data type must match. Because the ID column in the species table is of type INT, we should make our Species column in the Animals table also of type INT. Secondly, to make this a foreign key we add REFERENCES Species(ID) to the Species column. DROP TABLE IF EXISTS Animals; CREATE TABLE Animals( ID INT PRIMARY KEY IDENTITY, Name VARCHAR(50) NOT NULL, Species INT NOT NULL REFERENCES Species(ID), ContactEmail VARCHAR(50) NOT NULL UNIQUE ); ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Support me! http://www.patreon.com/calebcurry Subscribe to my newsletter: http://bit.ly/JoinCCNewsletter Donate!: http://bit.ly/DonateCTVM2. ~~~~~~~~~~~~~~~Additional Links~~~~~~~~~~~~~~~ More content: http://CalebCurry.com Facebook: http://www.facebook.com/CalebTheVideoMaker Google+: https://plus.google.com/+CalebTheVideoMaker2 Twitter: http://twitter.com/calebCurry Amazing Web Hosting - http://bit.ly/ccbluehost (The best web hosting for a cheap price!)
Views: 10403 Caleb Curry
[en] SQL Developer- How to find which tables reference a given table in Oracle SQL Developer?
 
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The table can reference to one or more tables, and also be referenced by others. We are able to show it on the model tab of Oracle SQL Developer. Tiếng Việt: https://youtu.be/qhxEDL4_UY0
Views: 85 1Click2beDBA
Oracle - SQL - Truncate Table
 
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Oracle - SQL - Truncate Table Watch more Videos at https://www.tutorialspoint.com/videotutorials/index.htm Lecture By: Mr. Anadi Sharma, Tutorials Point India Private Limited.
Oracle SQL Tutorial 16 - Parent Child Relationships
 
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So far in this series we have discussed database design, creating tables, and constraints. We've brought up the concept of foreign keys, but we have not explained how to create them. That is the goal of this video and the upcoming videos. We want to study those foreign keys! Let's make them not so foreign. Let's learn the proper way to define a foreign key. As a reminder, a foreign key is a column that references a column of another table. The column it references must either be a primary key, or have the UNIQUE constraint. This means that every value inside of the column that is labeled as a foreign key, there must be that value in some row of the referenced column. As an example, imagine that we have the users table, and we have a table service_requests. We could have a column in the service_request that references a column in the users table. Usually this would be the primary key that is referenced, but there is nothing stopping you from referencing a unique column. Just for fun, let's go through an example using the username column. If we have a service_requests table, every single row within the table is going to be what some would consider an instance of a service_request. This means that the table columns are like the blueprint for what a service request looks like and then each row is an individual service request. If we have one of the columns labeled as a foreign key to the username of the users table, what does that mean practically? It means that for a single row, the value for that column must be a value that exists in the users table. We could have a service_request submitted by a user with the username of Yoloswagman. This means that there must be a row inside of the users table that has the value Yoloswagman for the username column. This brings up the concept of parent and child relationships. Yoloswagman in this situation is the parent, and his service request is the child. When we draw it out, it makes sense why a primary key must be UNIQUE. If we had two Yoloswagmans, the child would not know which column is the parent. The same applies if we were using IDs and we had So remember, always reference a primary key or a column with the UNIQUE constraint. Now, I have a question for you. Do foreign keys automatically have the UNIQUE constraint, just like primary keys? The answer is no. A parent row can have many child rows. It makes sense because the user could submit multiple service requests. Can we force the column to be unique? Absolutely. If that was the case, the user could only make one service request. Another question. Do foreign keys automatically have the NOT NULL constraint, just like primary keys? The answer is no. Essentially what this means is that a child could be created with no parent. Can we force the column to be NOT NULL? Absolutely. It is ok in some situations to allow the row to be null, but in this situation it makes no sense. It would be wise for us to add that constraint ourselves. So now that you understand some more differences between primary and foreign keys and parent child relationships, take all of these questions into consideration when you are creating foreign keys. In the next video, we are going to start a small project that is going to require multiple tables. We'll take a video to design our structure and then we'll get to creating those foreign keys in Oracle SQL Developer. Stick around and if you like these videos please be a serious supporter and subscribe to my channel. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ HELP ME! http://www.patreon.com/calebcurry Subscribe to my newsletter: http://bit.ly/JoinCCNewsletter Donate!: http://bit.ly/DonateCTVM2. ~~~~~~~~~~~~~~~Additional Links~~~~~~~~~~~~~~~ More content: http://CalebCurry.com Facebook: http://www.facebook.com/CalebTheVideoMaker Google+: https://plus.google.com/+CalebTheVideoMaker2 Twitter: http://twitter.com/calebCurry Amazing Web Hosting - http://bit.ly/ccbluehost (The best web hosting for a cheap price!)
Views: 14816 Caleb Curry
Database Design 50 - Self Join
 
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This video will dive into the topic of self joins. Self joins are when you join a table with itself. This can be useful for replacing values within the table or having more than one of the same column for some reason. Self Joins can definitely be complicated! Donate!: http://bit.ly/DonateCTVM2. More content: http://CalebCurry.com Courses for Download: http://www.udemy.com/u/calebcurry/ (Use the coupon code "YouTubeDiscount" without the quotes) Facebook: http://www.facebook.com/CalebTheVideoMaker Google+: https://plus.google.com/+CalebTheVideoMaker2 Twitter: http://Twitter.com/calebCurry Subscribe (it's free!): https://www.youtube.com/channel/UCZUyPT9DkJWmS_DzdOi7RIA?sub_confirmation=1 Amazing Web Hosting - http://bit.ly/ccbluehost (The best web hosting for a cheap price!)
Views: 21416 Caleb Curry
IO6: Querying Files with the External Table Feature
 
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The external table feature of Oracle Database allows you apply SQL SELECT operations to the contents of files. Download my demo.zip from v.gd/sfdemo to access and run all referenced scripts. This video was taken from PLSQLChannel.com, originally recorded before Steven Feuerstein re-joined Oracle in March 2014. ======================================== Practically Perfect PL/SQL with Steven Feuerstein Copyright © 2015 Oracle and/or its affiliates. Oracle is a registered trademark of Oracle and/or its affiliates. All rights reserved. Other names may be registered trademarks of their respective owners. Oracle disclaims any warranties or representations as to the accuracy or completeness of this recording, demonstration, and/or written materials (the “Materials”). The Materials are provided “as is” without any warranty of any kind, either express or implied, including without limitation warranties or merchantability, fitness for a particular purpose, and non-infringement.
Foreign Key | Database Management System
 
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To ask your doubts on this topic and much more, click on this Direct Link: http://www.techtud.com/video-lecture/lecture-foreign-key IMPORTANT LINKS: 1) Official Website: http://www.techtud.com/ 2) Virtual GATE: http://virtualgate.in/login/index.php Both of the above mentioned platforms are COMPLETELY FREE, so feel free to Explore, Learn, Practice & Share! Our Social Media Links: Facebook Page: https://www.facebook.com/techtuduniversity Facebook Group: https://www.facebook.com/groups/virtualgate Google+ Page: https://plus.google.com/+techtud/posts Last but not the least, SUBSCRIBE our YouTube channel to stay updated about the regularly uploaded new videos.
Views: 281279 Techtud
Connect Excel to Oracle Database
 
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How to connect an Oracle Database to Microsoft Excel. https://www.elance.com/s/edtemb/
Views: 105861 i_marketing
SQL 12c Tutorial 22 : SQL 12c Feature TRUNCATE TABLE With CASCADE option
 
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SQL 12c Tutorial 22 : SQL 12c Feature TRUNCATE TABLE With CASCADE option SQL 12c New Features SQL 12c Tutorial for beginners Oracle SQL 12c Tutorial for beginners
Views: 995 TechLake
SQL TUTORIAL - SELF JOINS Hierarchy Tables
 
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Another video brought to you by BeardedDev, bringing you tutorials on Business Intelligence, SQL Programming and Data Analysis. You can now support me on patreon - https://www.patreon.com/beardeddev This SQL Tutorial is all about hierarchy tables and self joins. We start off by looking at hierarchies that we are all aware of such as Parent and Child. The video then describes how we can create a hierarchy table in SQL Server including a Primary Key and a Foreign Key that references the Primary Key in the same table. If you are new to working with constraints in SQL Server please check out these videos: SQL Tutorial - Primary Key Constraints: https://youtu.be/DJ054rHGhRw SQL Tutorial - Create Table with Constraints: https://youtu.be/bfBnZKf2EGg If you would like to follow along with this SQL Tutorial then this is the create table statement used: CREATE TABLE dbo.Staff ( StaffId INT IDENTITY(1, 1) NOT NULL CONSTRAINT PK_Staff_StaffId PRIMARY KEY (StaffId) , StaffTitle VARCHAR(50) NOT NULL , ManagerId INT NULL CONSTRAINT FK_Staff_ManagerId FOREIGN KEY (ManagerId) REFERENCES dbo.Staff (StaffId) ) We then insert some dummy data in to the Hierarchy table and have a look at the results when executing a SELECT statement. On to discussing Self Joins, and the difference between using an INNER JOIN and a LEFT OUTER JOIN when joining a table to itself although the same applies if you were joining two separate underlying tables together. Then we apply a Self Join and return results, as the table and columns are the same we need to apply aliases. SELECT A.StaffTitle , B.StaffTitle AS ReportsTo FROM dbo.Staff AS A LEFT OUTER JOIN dbo.Staff AS B ON A.ManagerId = B.StaffId
Views: 441 BeardedDev
Oracle SQL Tutorial 17 - Designing Our Foreign Keys
 
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We are going to continue working with the users table that we've started with, but we are going to add a few tables. Imagine a system where you can create projects. And users can be added to these projects. So this could be some kind of productivity app or a project management solution, think of JIRA. We are going to start with three tables. The first table is going to be a users table that contains all of the information about each user's account. We are then going to have a table that is called projects. Each project will have data about the project and a foreign key that is the creator of the project. This is a situation where the database design depends a lot on the business rules and requirements of the application. Is it appropriate to have only one creator, or can it have multiple creators? We are going to design it with only one creator per project to increase simplicity. The third table is going to be used to record what users are part of certain projects. This situation is a many to many relationship because we've decided that one user can be a part of multiple projects and an individual project can have multiple members working on it. Because this is a many to many relationship, it calls for an intermediary table, project_users. First, we will draw out the user table. We will have a user_id, username, first_name, and last_name. Now, this is our parent table, because it has no foreign keys. Now, this is our parent table, because it has no foreign keys. Other tables are going to be referencing this table, so they would be the children. The project table will have a project_id, title, description, and creator. The column that needs to be a foreign key is the creator. Let's move on to the next table and we'll get back to the foreign key of the project table. The other table was project_users. Knowing that this is an intermediary table, immediately we know that the first two columns are going to be foreign keys to the each of the other tables. Now, let's ask the important questions about the foreign keys. Let's first start with the project table's user column. The first thing we need to ask is what column does it need to reference? Remember, the only options are the columns that are UNIQUE. Our candidates are user_id and username. For now, let's go with username as it makes things easier to work with. Once we go into learning about joins, we will talk about joining things by ID. Different people do it different ways, with the majority using only ID columns for primary and foreign keys, but it's important to be familiar with different ways of doing things. The important thing to remember is that keys should never change, so if we should only reference the username if a user's username will never change. Should the foreign key be labeled UNIQUE? If yes, it means that a user can only create one project. I vote no. Should the foreign key be labeled NOT NULL? If not, it means that a project can exist without a creator. I vote no. Moving on to the next table, I think I'll have the columns reference the project's id and user's id, so we can get some experience referencing surrogate keys. We can apply to these foreign keys the same questions we asked about the other foreign key, and I would encourage you to do so and really think about why. But I can tell you that we are not going to want them to be NOT NULL, but not UNIQUE. Now that we have a pretty decent database design, we can proceed with creating our database. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ HELP ME! http://www.patreon.com/calebcurry Subscribe to my newsletter: http://bit.ly/JoinCCNewsletter Donate!: http://bit.ly/DonateCTVM2. ~~~~~~~~~~~~~~~Additional Links~~~~~~~~~~~~~~~ More content: http://CalebCurry.com Facebook: http://www.facebook.com/CalebTheVideoMaker Google+: https://plus.google.com/+CalebTheVideoMaker2 Twitter: http://twitter.com/calebCurry Amazing Web Hosting - http://bit.ly/ccbluehost (The best web hosting for a cheap price!)
Views: 11671 Caleb Curry
SQL Tutorial - 13: Inserting Data Into a Table From Another Table
 
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In this tutorial we'll learn to use the INSERT Query to copy data from one table into another.
Views: 269476 The Bad Tutorials
Oracle SQL Tutorial 15 - How to Add Primary Key Constraints
 
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The goal of this video is to take the CREATE TABLE statement we have and walk through the different ways to create primary keys. This and foreign keys are the most common constraints, so we need to make sure that you have this one down. Once we have a more complex database design with multiple tables, we will learn the proper way to create foreign keys. For now, I am going to keep all of our constraints at the column level, unnamed. The only exception is the primary key, because that is what we are focusing on in this video. The first way to create the primary key is at the column level, unnamed. The primary key is very important because it what we use to distinguish rows from one another. Every table you create is going to need a primary key, and I suggest putting a lot of effort into making sure your keys are set up correctly and organized. --Delete the table if needed: DROP TABLE users; CREATE TABLE users( user_id NUMBER PRIMARY KEY, username VARCHAR2(50 CHAR) NOT NULL UNIQUE ) The next way is at the column level, but named: --Delete the table: DROP TABLE users; CREATE TABLE users( user_id NUMBER CONSTRAINT users_pk PRIMARY KEY, username VARCHAR2(50 CHAR)NOT NULL UNIQUE ) The general naming convention here is the table name followed by an underscore, followed by pk for primary key. Finally, the third way, which is at the table level, is the way we are going to create our primary key: --Delete the table: DROP TABLE users; CREATE TABLE users( user_id NUMBER, username VARCHAR2(50 CHAR) NOT NULL UNIQUE, CONSTRAINT users_pk PRIMARY KEY (user_id) ) Now, once you've created these constraints, you can use Oracle SQL Developer to find these constraints. Open your databases in the connections tab and find the table in the Tables folder. Double click your table and travel to the Constraints tab. You can tell here that the UNIQUE constraint still exists in this table, but it has a pretty disgusting name. It kind of wants to make me puke. Referencing that constraint in the future with that wacky name would be a burden. Engrave these three options in your head so that you can use any of them whenever you need and can read other peoples' code. Thank you for sticking with the series thus far. In the next video, we will be…doing something. See you then! :) ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Support me on Patreon! http://www.patreon.com/calebcurry Subscribe to my newsletter: http://bit.ly/JoinCCNewsletter Donate!: http://bit.ly/DonateCTVM2. ~~~~~~~~~~~~~~~Additional Links~~~~~~~~~~~~~~~ More content: http://CalebCurry.com Facebook: http://www.facebook.com/CalebTheVideoMaker Google+: https://plus.google.com/+CalebTheVideoMaker2 Twitter: http://twitter.com/calebCurry Amazing Web Hosting - http://bit.ly/ccbluehost (The best web hosting for a cheap price!)
Views: 17593 Caleb Curry
Oracle SQL Tutorial 19 - ON DELETE (SET NULL and CASCADE)
 
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Welcome everyone! Something you need to consider when you are creating foreign keys is what happens if you delete the parent? As a reminder, the parent is the row that has the value you are referencing in the row that has a foreign key. Why is this something important to consider? It's important because foreign keys need to protect us from two primary things, unacceptable INSERT statements, and unacceptable DELETE statements. Let's see what happens when we try to insert incorrect data into the table with the foreign key: INSERT INTO projects VALUES (1, 'Update website homepage', 'CalebCurry') The response tells us plainly that there is no such user in the users table. So this works correctly. Deleting data on the other hand works a bit differently because the database does not know what you want to do with the child row when you delete the parent from the parent table. By default, we will get an error message that prevents the parent from being deleted, but there are some other options. How do we configure this? This is where the ON DELETE statement comes in. We add the keywords ON DELETE right after the foreign key and then we can give it the option of CASCADE or SET NULL. CASCADE means that if we delete the parent, we are also going to delete the child. In our situation what that means is that if somebody creates a project in our project table and then that persons account gets deleted, all of the projects he owns will also be deleted. CASCADE: CREATE TABLE projects( project_id NUMBER, Project_name VARCHAR2(50 CHAR) UNIQUE, creator VARCHAR2(50 CHAR) NOT NULL, CONSTRAINT projects_pk PRIMARY KEY (project_id), CONSTRAINT projects_users_fk FOREIGN KEY (creator) REFERENCES users (username) ON DELETE CASCADE ) SET NULL will take the value in the child table and get rid of it. What you are left with is NULL. This means that we have an orphaned child. The first thought you might have is that it is a bad thing to have an orphaned child, but in databases that is not always so. In our application if we had it set to SET NULL, when a user account gets deleted the projects would remain in existence they would just lack a creator. This might be a good thing if you are concerned about the long term survival of a project, this might be the route you want to go. It ultimately depends on the application purpose. If you don't like CASCADE or SET NULL, you can leave the entire ON DELETE statement and just have Oracle throw an error when a parent is deleted. As for us, we are going to use ON DELETE CASCADE. We need to use this with extreme caution. If you are not careful, someday you will run a delete a row and that will cascade through you database deleting a bunch of stuff you didn't want to delete. Stuff happens, so make sure you back up your database every once in eternity. Now, in the last video we started with a database design that had three tables. We've only created two in this video. In the next video we are going to create the next one, which is a little special. Then we'll finish things up by adding some indexes. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Support me on Patreon! http://www.patreon.com/calebcurry Subscribe to my newsletter: http://bit.ly/JoinCCNewsletter Donate!: http://bit.ly/DonateCTVM2. ~~~~~~~~~~~~~~~Additional Links~~~~~~~~~~~~~~~ More content: http://CalebCurry.com Facebook: http://www.facebook.com/CalebTheVideoMaker Google+: https://plus.google.com/+CalebTheVideoMaker2 Twitter: http://twitter.com/calebCurry Amazing Web Hosting - http://bit.ly/ccbluehost (The best web hosting for a cheap price!)
Views: 19046 Caleb Curry
sql - how to delete data from table which has self referencing foreign key column
 
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UPDATE employee SET manager_id=NULL DELETE FROM employee How to delete data from Table which has self referecing foreign key In this table Manager_Id is referring customer_id Now we try to delete data from this table Error Code: 1451 Cannot delete or update a parent row: a foreign key constraint fails (`my_retail_data`.`employee`, CONSTRAINT `employee_fk0` FOREIGN KEY (`manager_id`) REFERENCES `employee` (`employee_id`)) to overcome, first we need set data in mangaer_id column as nulls Try, deleting data now from the Employee table Done!
Views: 627 Data Disc
Lec-33: Self Join operation with Example | Database Management System
 
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#SelfJoin #SQlDBMS #FreeEducationGATE
Views: 61561 Gate Smashers
Oracle APEX Tutorial 04 - Create Table and Insert Row Using Object Browser
 
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Hi! I’m Abdulrhman Uthman, a student of King Faisal University in Saudi Arabia. This series is intended for the practical class of Database Concepts students in our university, but anyone who wants to learn database, SQL or Structured Query Language and use Oracle’s APEX are welcome aboard. In this video, we will use APEX to create a table and insert rows using object browser. I would like to acknowledge the following people for their support: Dr. Majed Alshamari, Dr. Mohammed Bonais, Dr. Abdullah Alaulaimie, Dr. Mohammed Al-Naeem, Mr. Ahmed Alshawayrid, Mr. Naif Bo-Hasan, Mr. Mohammed Tawfiq, my sister, Ms. Reem Uthman, and my brother, Anas Uthman for editing the video.
Views: 1480 Abdulrhman Uthman
SQL script to insert into many to many table
 
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Text Article http://csharp-video-tutorials.blogspot.com/2017/02/sql-script-to-insert-into-many-to-many.html Slides http://csharp-video-tutorials.blogspot.com/2017/02/sql-script-to-insert-into-many-to-many_6.html SQL Server Interview Questions and Answers text articles & slides http://csharp-video-tutorials.blogspot.com/2014/05/sql-server-interview-questions-and.html SQL Server Interview Questions and Answers playlist https://www.youtube.com/playlist?list=PL6n9fhu94yhXcztdLO7i6mdyaegC8CJwR All Dot Net and SQL Server Tutorials in English https://www.youtube.com/user/kudvenkat/playlists?view=1&sort=dd All Dot Net and SQL Server Tutorials in Arabic https://www.youtube.com/c/KudvenkatArabic/playlists In this video we will discuss how to insert data into a table that has many-to-many relationship Create table Students ( Id int primary key identity, StudentName nvarchar(50) ) Go Create table Courses ( Id int primary key identity, CourseName nvarchar(50) ) Go Create table StudentCourses ( StudentId int not null foreign key references Students(Id), CourseId int not null foreign key references Courses(Id) ) Go Students - Id column is identity column Courses - Id column is identity column StudentCourses - StudentId and CourseId columns are foreign keys referencing Id column in Students and Courses tables As you can see, StudentCourses is a bridge table that has many to many relationship with Students and Courses tables. This means a given student can be enrolled into many courses and a given course can have many students enrolled. Below is the question asked in an interview for SQL Server Developer role. Write a SQL script to insert data into StudentCourses table. Here are the rules that your script should follow. 1. There will be 2 inputs for the script Student Name - The name of the student who wants to enroll into a course Course Name - The name of the course the student wants to enroll into 2. If the student is already in the Students table, then use that existing Student Id. If the student is not already in the Students table, then a row for that student must be inserted into the Students table, and use that new student id. 3. Along the same lines, if the course is already in the Courses table, then use that existing Course Id. If the course is not already in the Courses table, then a row for that course must be inserted into the Courses table, and use that new course id. 4. There should be no duplicate student course enrollments, i.e a given student must not be enrolled in the same course twice. For example, Tom must not be enrolled in C# course twice. Answer : To avoid duplicate student course enrollments create a composite primary key on StudentId and CourseId columns in StudentCourses table. With this composite primary key in place, if someone tries to enroll the same student in the same course again we get violation of primary key constraint error. Alter table StudentCourses Add Constraint PK_StudentCourses Primary Key Clustered (CourseId, StudentId) Here is the SQL script that inserts data into the 3 tables as expected Declare @StudentName nvarchar(50) = 'Sam' Declare @CourseName nvarchar(50) = 'SQL Server' Declare @StudentId int Declare @CourseId int -- If the student already exists, use the existing student ID Select @StudentId = Id from Students where StudentName = @StudentName -- If the course already exists, use the existing course ID Select @CourseId = Id from Courses where CourseName = @CourseName -- If the student does not exist in the Students table If (@StudentId is null) Begin -- Insert the student Insert into Students values(@StudentName) -- Get the Id of the student Select @StudentId = SCOPE_IDENTITY() End -- If the course does not exist in the Courses table If (@CourseId is null) Begin -- Insert the course Insert into Courses values(@CourseName) -- Get the Id of the course Select @CourseId = SCOPE_IDENTITY() End -- Insert StudentId & CourseId in StudentCourses table Insert into StudentCourses values(@StudentId, @CourseId) If required, we can very easily convert this into a stored procedure as shown below. Create procedure spInsertIntoStudentCourses @StudentName nvarchar(50), @CourseName nvarchar(50) as Begin Declare @StudentId int Declare @CourseId int Select @StudentId = Id from Students where StudentName = @StudentName Select @CourseId = Id from Courses where CourseName = @CourseName If (@StudentId is null) Begin Insert into Students values(@StudentName) Select @StudentId = SCOPE_IDENTITY() End If (@CourseId is null) Begin Insert into Courses values(@CourseName) Select @CourseId = SCOPE_IDENTITY() End Insert into StudentCourses values(@StudentId, @CourseId) End Use the following statement to execute the stored procedure Execute spInsertIntoStudentCourses 'Tom','C#'
Views: 96594 kudvenkat
Simple Recursion in SQL
 
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A simple example of recursion using SQL Server and Common Table Expressions (CTEs). Thanks to +Nikola Gujanicic for the request.
Views: 26875 Database by Doug
Primary Key & Foreign Key Implementation: MySQL
 
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http://technotip.com/2931/primary-key-foreign-key-implementation-mysql/ Implementation of Primary Key and Foreign Key, using MySQL Practical approach and the benefits of using Primary and Foreign key concept in a relational database design.
Views: 246327 Satish B
IO4: Rename, Move, Copy Files with UTL_FILE
 
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UTL_FILE offers a number of high-level subprograms to perform activities like copying a file, renaming a file, and removing a file. Download my demo.zip from v.gd/sfdemo to access and run all referenced scripts. This video was taken from PLSQLChannel.com, originally recorded before Steven Feuerstein re-joined Oracle in March 2014. ======================================== Practically Perfect PL/SQL with Steven Feuerstein Copyright © 2015 Oracle and/or its affiliates. Oracle is a registered trademark of Oracle and/or its affiliates. All rights reserved. Other names may be registered trademarks of their respective owners. Oracle disclaims any warranties or representations as to the accuracy or completeness of this recording, demonstration, and/or written materials (the “Materials”). The Materials are provided “as is” without any warranty of any kind, either express or implied, including without limitation warranties or merchantability, fitness for a particular purpose, and non-infringement.
CTE in sql server   Part 49
 
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In this video we will learn about creating and referencing CTE's in SQL server. We will also learn how to create multiple CTE's using a single WITH clause. Text version of the video http://csharp-video-tutorials.blogspot.com/2012/09/common-table-expressions-part-49.html Slides http://csharp-video-tutorials.blogspot.com/2013/09/part-49-cte.html All SQL Server Text Articles http://csharp-video-tutorials.blogspot.com/p/free-sql-server-video-tutorials-for.html All SQL Server Slides http://csharp-video-tutorials.blogspot.com/p/sql-server.html All Dot Net and SQL Server Tutorials in English https://www.youtube.com/user/kudvenkat/playlists?view=1&sort=dd All Dot Net and SQL Server Tutorials in Arabic https://www.youtube.com/c/KudvenkatArabic/playlists
Views: 199031 kudvenkat
How to Drop Foreign Key Constraint in SQL Server Database - SQL Server / TSQL Tutorial Part 75
 
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SQL Server / T-SQL Tutorial Scenario: You are working as SQL Server developer and you need to prepare the script to drop the Foreign Key Constraint which was created on dbo.Orders table. Link to scripts used in SQL Server / TSQL Tutorial Video http://www.techbrothersit.com/2016/04/how-to-drop-foreign-key-constraint-in.html Check out our website for Different SQL Server, MSBI tutorials and interview questions such as SQL Server Reporting Services(SSRS) Tutorial SQL Server Integration Services(SSIS) Tutorial SQL Server DBA Tutorial SQL Server / TSQL Tutorial ( Beginner to Advance) http://www.techbrothersit.com/
Views: 4488 TechBrothersIT
How to create Virtual Columns in Oracle Database
 
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How to create Virtual Columns in Oracle Database 12c When queried, virtual columns appear to be normal table columns, but their values are derived rather than being stored on disc. The syntax for defining a virtual column is listed below. column_name [datatype] [GENERATED ALWAYS] AS (expression) [VIRTUAL] If the datatype is omitted, it is determined based on the result of the expression. The GENERATED ALWAYS and VIRTUAL keywords are provided for clarity only. The script below creates and populates an employees table with two levels of commission. It includes two virtual columns to display the commission-based salary. The first uses the most abbreviated syntax while the second uses the most verbose form. CREATE TABLE employees ( id NUMBER, first_name VARCHAR2(10), last_name VARCHAR2(10), salary NUMBER(9,2), comm1 NUMBER(3), comm2 NUMBER(3), salary1 AS (ROUND(salary*(1+comm1/100),2)), salary2 NUMBER GENERATED ALWAYS AS (ROUND(salary*(1+comm2/100),2)) VIRTUAL, CONSTRAINT employees_pk PRIMARY KEY (id) ); INSERT INTO employees (id, first_name, last_name, salary, comm1, comm2) VALUES (1, 'JOHN', 'DOE', 100, 5, 10); INSERT INTO employees (id, first_name, last_name, salary, comm1, comm2) VALUES (2, 'JAYNE', 'DOE', 200, 10, 20); COMMIT; Querying the table shows the inserted data plus the derived commission-based salaries. SELECT * FROM employees; ID FIRST_NAME LAST_NAME SALARY COMM1 COMM2 SALARY1 SALARY2 ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- 1 JOHN DOE 100 5 10 105 110 2 JAYNE DOE 200 10 20 220 240 2 rows selected. SQL The expression used to generate the virtual column is listed in the DATA_DEFAULT column of the [DBA|ALL|USER]_TAB_COLUMNS views. COLUMN data_default FORMAT A50 SELECT column_name, data_default FROM user_tab_columns WHERE table_name = 'EMPLOYEES'; COLUMN_NAME DATA_DEFAULT ------------------------------ -------------------------------------------------- ID FIRST_NAME LAST_NAME SALARY COMM1 COMM2 SALARY1 ROUND("SALARY"*(1+"COMM1"/100),2) SALARY2 ROUND("SALARY"*(1+"COMM2"/100),2) 8 rows selected. SQL Notes and restrictions on virtual columns include: 1)Indexes defined against virtual columns are equivalent to function-based indexes. 2)Virtual columns can be referenced in the WHERE clause of updates and deletes, but they cannot be manipulated by DML. 3)Tables containing virtual columns can still be eligible for result caching. 4)Functions in expressions must be deterministic at the time of table creation, but can subsequently be recompiled and made non-deterministic without invalidating the virtual column. In such cases the following steps must be taken after the function is recompiled: a)Constraint on the virtual column must be disabled and re-enabled. b)Indexes on the virtual column must be rebuilt. c)Materialized views that access the virtual column must be fully refreshed. d)The result cache must be flushed if cached queries have accessed the virtual column. e)Table statistics must be regathered. 5)Virtual columns are not supported for index-organized, external, object, cluster, or temporary tables. 6)The expression used in the virtual column definition has the following restrictions: a.It cannot refer to another virtual column by name. b.It can only refer to columns defined in the same table. c.If it refers to a deterministic user-defined function, it cannot be used as a partitioning key column. e.The output of the expression must be a scalar value. It cannot return an Oracle supplied datatype, a user-defined type, or LOB or LONG RAW.
Views: 564 OracleDBA
Oracle Database | Bangla Tutorials 31 :: Truncate Table |(Remove all Record a Table)
 
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www.facebook.com/oracle.shohag Email : [email protected] Website : www.oraclebangla.com skype id : shoahgcid2013 Topics :Truncate Table
Views: 2999 Oracle Bangla
PRIMARY KEY AT TABLE CREATION ORACLE 10G SQL * PLUS
 
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#Rohitkautkar #rohit #kautkar PRIMARY KEY AT TABLE CREATION ORACLE 10G SQL * PLUS
Views: 21 Rohit Kautkar
PL/SQL tutorial 57: PL/SQL Collection Associative Array in Oracle Database
 
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Manish Sharma from RebellionRider presents you the latest PL/SQL tutorial on Collection ASSOCIATIVE ARRAY. In this video, you will learn – - What are Associative Arrays? - How to create Associative Arrays? - How to Insert & Update the data of Associative Array and - How to retrieve the data from an Associative array using two different ways? So if you are wondering whether associative array is a persistent form of collection or not; Is it bounded or unbounded in nature; why should we use this specific collection over others such as VARRAY or Nested Table; What are the differences or similarities between associative array and other collections? Then go ahead and watch the video to find out the answers to all these questions. Hope you will enjoy watching. Do make sure to Like and Share this post/video because that will help others in learning as well as help me and my channel in reaching out. This way we can educate more and more people for FREE. Most importantly SUBSCRIBE to the channel as many such interesting tutorials are coming your way. Thanks. ------------------------------------------------------------------------ ►►►LINKS◄◄◄ Blog: http://bit.ly/associative-array Previous Tutorial ►While Loop: https://youtu.be/IIlc4Sr7kFE ------------------------------------------------------------------------- ►Make sure you SUBSCRIBE and be the 1st one to see my videos! ------------------------------------------------------------------------- ►►►Find me on Social Media◄◄◄ Follow What I am up to as it happens on https://twitter.com/rebellionrider http://instagram.com/rebellionrider https://plus.google.com/+Rebellionrider http://in.linkedin.com/in/mannbhardwaj/ ___Facebook Official Page of Manish Sharma___ https://www.facebook.com/TheRebellionRider/ ___Facebook Official Page of RebellionRider.com___ https://www.facebook.com/RebellionRider.official/ You can also Email me at for E-mail address please check the About section Please please LIKE and SHARE my videos it makes me happy. Thanks for liking, commenting, sharing and watching more of our videos This is Manish from RebellionRider.com ♥ I LOVE ALL MY VIEWERS AND SUBSCRIBERS
Views: 14973 Manish Sharma
Oracle SQL Tutorial 20 - How to Create Composite Primary Keys
 
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This video is going to be a tutorial on how to create composite and compound keys. The difference between a composite and compound key is that a composite key can consist of any columns while a compound key has to consist of columns that are all keys themselves. We will be working with a compound key because we are going to be using the an intermediary table that has two foreign keys. The combination of both of the keys have to be unique. First, if we have any other CREATE TABLE commands, we are going to comment those out. We will space out the CREATE TABLE to have each column on a line, then we will add constraints as needed. CREATE TABLE project_users( project_id, user_id ) Now, let's add the data types: CREATE TABLE project_users( project_id NUMBER, user_id NUMBER } Now, what about some column attributes? I'm going to make both of the columns NOT NULL because we always want the rows to have a user and a project: CREATE TABLE project_users( project_id NUMBER NOT NULL, user_id NUMBER NOT NULL } Now, let's add the foreign key constraints. Now, what do we name these? We are going to add a primary key that covers both of these columns, so I'm going to be a sinner and not give these constraints names: CREATE TABLE project_users( project_id NUMBER NOT NULL REFERENCES projects (project_id), user_id NUMBER NOT NULL REFFERENCES users (user_id) ) Now, the way we have it now is that if we delete a project in the project table, and there are any rows in the project_users table, it will throw an error and prevent deletion. I would prefer for it to also delete any project members. That would make sense because if you delete a project we want it to delete the associate between that project and certain users. The same goes for if we delete a user, we want their association with a certain project to be deleted. To do this, we need to add the ON DELETE command: CREATE TABLE project_users( project_id NUMBER NOT NULL REFERENCES projects (project_id) ON DELETE CASCADE, user_id NUMBER NOT NULL REFERENCES users (user_id) ON DELETE CASCADE, ) Finally, let's learn how to create a compound or composite key. literally, the only difference is that you put a comma and add the second table inside of the parenthesis. CREATE TABLE project_users( project_id NUMBER NOT NULL REFERENCES projects (project_id) ON DELETE CASCADE, user_id NUMBER NOT NULL REFERENCES users (user_id) ON DELETE CASCADE, CONSTRAINT project_users_pk PRIMARY KEY (project_id, user_id) ) Now, the combination of project_id and user_id cannot be null, is always unique, and has an index. The only thing we should do now is add a few indexes. We aren't done yet...In the next video we are going to figure out what columns would benefit from indexes and we'll add them to it. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ HELP ME! http://www.patreon.com/calebcurry Subscribe to my newsletter: http://bit.ly/JoinCCNewsletter Donate!: http://bit.ly/DonateCTVM2. ~~~~~~~~~~~~~~~Additional Links~~~~~~~~~~~~~~~ More content: http://CalebCurry.com Facebook: http://www.facebook.com/CalebTheVideoMaker Google+: https://plus.google.com/+CalebTheVideoMaker2 Twitter: http://twitter.com/calebCurry Amazing Web Hosting - http://bit.ly/ccbluehost (The best web hosting for a cheap price!)
Views: 12942 Caleb Curry
Difference between rows and range
 
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range vs rows in sql server difference between rows clause and range clause in sql server range clause vs rows clause in sql server sql server running total query running total example in sql server In this video we will discuss the difference between rows and range in SQL Server. This is continuation to Part 116. Please watch Part 116 from SQL Server tutorial before proceeding. Let us understand the difference with an example. We will use the following Employees table in this demo. SQL Script to create the Employees table Create Table Employees ( Id int primary key, Name nvarchar(50), Salary int ) Go Insert Into Employees Values (1, 'Mark', 1000) Insert Into Employees Values (2, 'John', 2000) Insert Into Employees Values (3, 'Pam', 3000) Insert Into Employees Values (4, 'Sara', 4000) Insert Into Employees Values (5, 'Todd', 5000) Go Calculate the running total of Salary and display it against every employee row The following query calculates the running total. We have not specified an explicit value for ROWS or RANGE clause. SELECT Name, Salary, SUM(Salary) OVER(ORDER BY Salary) AS RunningTotal FROM Employees So the above query is using the default value which is RANGE BETWEEN UNBOUNDED PRECEDING AND CURRENT ROW This means the above query can be re-written using an explicit value for ROWS or RANGE clause as shown below. SELECT Name, Salary, SUM(Salary) OVER(ORDER BY Salary RANGE BETWEEN UNBOUNDED PRECEDING AND CURRENT ROW) AS RunningTotal FROM Employees We can also achieve the same result, by replacing RANGE with ROWS SELECT Name, Salary, SUM(Salary) OVER(ORDER BY Salary ROWS BETWEEN UNBOUNDED PRECEDING AND CURRENT ROW) AS RunningTotal FROM Employees What is the difference between ROWS and RANGE To understand the difference we need some duplicate values for the Salary column in the Employees table. Execute the following UPDATE script to introduce duplicate values in the Salary column Update Employees set Salary = 1000 where Id = 2 Update Employees set Salary = 3000 where Id = 4 Go Now execute the following query. Notice that we get the running total as expected. SELECT Name, Salary, SUM(Salary) OVER(ORDER BY Salary ROWS BETWEEN UNBOUNDED PRECEDING AND CURRENT ROW) AS RunningTotal FROM Employees The following query uses RANGE instead of ROWS SELECT Name, Salary, SUM(Salary) OVER(ORDER BY Salary RANGE BETWEEN UNBOUNDED PRECEDING AND CURRENT ROW) AS RunningTotal FROM Employees Notice we don't get the running total as expected. So, the main difference between ROWS and RANGE is in the way duplicate rows are treated. ROWS treat duplicates as distinct values, where as RANGE treats them as a single entity. All together side by side. The following query shows how running total changes 1. When no value is specified for ROWS or RANGE clause 2. When RANGE clause is used explicitly with it's default value 3. When ROWS clause is used instead of RANGE clause SELECT Name, Salary, SUM(Salary) OVER(ORDER BY Salary) AS [Default], SUM(Salary) OVER(ORDER BY Salary RANGE BETWEEN UNBOUNDED PRECEDING AND CURRENT ROW) AS [Range], SUM(Salary) OVER(ORDER BY Salary ROWS BETWEEN UNBOUNDED PRECEDING AND CURRENT ROW) AS [Rows] FROM Employees Text version of the video http://csharp-video-tutorials.blogspot.com/2015/10/difference-between-rows-and-range.html Slides http://csharp-video-tutorials.blogspot.com/2015/10/difference-between-rows-and-range_8.html All SQL Server Text Articles http://csharp-video-tutorials.blogspot.com/p/free-sql-server-video-tutorials-for.html All SQL Server Slides http://csharp-video-tutorials.blogspot.com/p/sql-server.html All Dot Net and SQL Server Tutorials in English https://www.youtube.com/user/kudvenkat/playlists?view=1&sort=dd All Dot Net and SQL Server Tutorials in Arabic https://www.youtube.com/c/KudvenkatArabic/playlists
Views: 36830 kudvenkat
SQL tutorial 24 :SQLJoins- Natural Join With ON and USING clause By Manish/Rebellionrider
 
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Connect with me on my LinkedIn and please endorse my Oracle database Skills LinkedIn : http://bit.ly/LinkedIn-Manish Links Web Link : http://bit.ly/natural-join Website : http://www.rebellionrider.com In This Tutorial You will learn What is Natural Join? How to use natural join. Natural Join with ON clause and Natural Join with Using clause Natural Joins with the USING Clause • If several columns have the same names but the data types do not match, natural join can be applied by using the USING clause to specify the columns that should be used for an equijoin. • Use the USING clause to match only one column when more than one column matches. • Do not use a table name or alias in the referenced columns. • The NATURAL JOIN and USING clauses are mutually exclusive. Tool used in this tutorial is SQL Developer. This tutorial series is part of SQL expert exam certification training. if you are preparing for SQL certification you can use my tutorials. This SQL Tutorial is a part of free training. Copy Cloud referral link || Use this link to join copy cloud and get 20GB of free storage https://copy.com?r=j7eYO7 Contacts E-Mail [email protected] Twitter https://twitter.com/rebellionrider Instagram http://instagram.com/rebellionrider Facebook. https://www.facebook.com/imthebhardwaj Linkedin. http://in.linkedin.com/in/mannbhardwaj/ Thanks for liking, commenting, sharing and watching more of our videos This is Manish from RebellionRider.com
Views: 74927 Manish Sharma
MySQL Database Tutorial - 22 - How to Join Tables
 
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Facebook - https://www.facebook.com/TheNewBoston-464114846956315/ GitHub - https://github.com/buckyroberts Google+ - https://plus.google.com/+BuckyRoberts LinkedIn - https://www.linkedin.com/in/buckyroberts reddit - https://www.reddit.com/r/thenewboston/ Support - https://www.patreon.com/thenewboston thenewboston - https://thenewboston.com/ Twitter - https://twitter.com/bucky_roberts
Views: 353333 thenewboston
107- Oracle SQL 12c: Manipulating Data- Explicit default value
 
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تعلم اوراكل حتى الاحتراف تعلم اوراكل من الصفر EXAM 1Z0-061 EXAM 1Z0-071
Views: 1031 khaled alkhudari
108. Drop Foreign Key from Table in SQL (Hindi)
 
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Please Subscribe Channel Like, Share and Comment Visit : www.geekyshows.com
Views: 8556 Geeky Shows
IO8: Sending mail from PL/SQL with UTL_MAIL
 
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Learn how to use the UTL_MAIL package to send mail from within your PL/SQL program. Download my demo.zip from v.gd/sfdemo to access and run all referenced scripts. This video was taken from PLSQLChannel.com, originally recorded before Steven Feuerstein re-joined Oracle in March 2014. ======================================== Practically Perfect PL/SQL with Steven Feuerstein Copyright © 2015 Oracle and/or its affiliates. Oracle is a registered trademark of Oracle and/or its affiliates. All rights reserved. Other names may be registered trademarks of their respective owners. Oracle disclaims any warranties or representations as to the accuracy or completeness of this recording, demonstration, and/or written materials (the “Materials”). The Materials are provided “as is” without any warranty of any kind, either express or implied, including without limitation warranties or merchantability, fitness for a particular purpose, and non-infringement.
Top PL/SQL Tips In Just One Hour
 
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Here's a video I recorded of a webcast to a team of developers who had one hour to spare to learn about some PL/SQL best practices. I offer tips on using compile time warnings, avoiding hard-coding/repetition, using nested subprograms and in the performance arena, lightning fast coverage of FORALL, function result cache, NOCOPY and PRAGMA UDF. Fun stuff and here's the guide: 03:00 Compile-time warnings 16:25 Don’t repeat anything 21:15 Tips on writing SQL in PL/SQL 24:50 Avoid hard-coding of formulas 28:35 Keep executable sections tiny 35:15 Avoid row-by-row processing 42:10 Function result cache 54:28 NOCOPY parameter hint 56:02 Optimizing user-defined function execution in SQL Files referenced in presentation may be found at http://www.oracle.com/webfolder/technetwork/tutorials/plsql/sfdemo.zip. But for the latest set of PL/SQL scripts, go to LiveSQL.oracle.com and search by keywords (forall, nocopy, etc.). More on PL/SQL at my blog https://stevenfeuersteinonplsql.blogspot.com PL/SQL quizzes, workouts and classes at https://devgym.oracle.com ======================================== Practically Perfect PL/SQL with Steven Feuerstein Copyright © 2018 Oracle and/or its affiliates. Oracle is a registered trademark of Oracle and/or its affiliates. All rights reserved. Other names may be registered trademarks of their respective owners. Oracle disclaims any warranties or representations as to the accuracy or completeness of this recording, demonstration, and/or written materials (the “Materials”). The Materials are provided “as is” without any warranty of any kind, either express or implied, including without limitation warranties or merchantability, fitness for a particular purpose, and non-infringement.
PL/SQL Tutorial | User Defined Exception | Pragma Exception_INIT in Oracle Database 11g
 
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Learn in depth with example about creating user defined exception using Pragma Exception_INIT and Raise_application_error following handling of different types of system named and unnamed exception in details. How to handle exception in oracle database, How to handle user defined exception in oracle database, What is Pragma in Exception Handling, What is Pragma Exception_INIT in oracle, Types of exception available in oracle, How to use Raise_application_error in oracle, How to use custom exception in oracle, How to use pragma autonomous transaction, SQLERRM, SQLCODE, Raise_application_error, In Oracle PL/SQL, PRAGMA refers to a compiler directive or "hint" it is used to provide an instruction to the compiler. The 5 types of Pragma directives available in Oracle are listed below: * PRAGMA AUTONOMOUS_TRANSACTION * PRAGMA SERIALLY_REUSABLE * PRAGMA RESTRICT_REFRENCES * PRAGMA EXCEPTION_INIT * PRAGMA INLINE Details of System Exception: DUP_VAL_ON_INDEX ORA-00001 You tried to execute an INSERT or UPDATE statement that has created a duplicate value in a field restricted by a unique index. TIMEOUT_ON_RESOURCE ORA-00051 You were waiting for a resource and you timed out. TRANSACTION_BACKED_OUT ORA-00061 The remote portion of a transaction has rolled back. INVALID_CURSOR ORA-01001 You tried to reference a cursor that does not yet exist. This may have happened because you've executed a FETCH cursor or CLOSE cursor before OPENing the cursor. NOT_LOGGED_ON ORA-01012 You tried to execute a call to Oracle before logging in. LOGIN_DENIED ORA-01017 You tried to log into Oracle with an invalid username/password combination. NO_DATA_FOUND ORA-01403 You tried one of the following: You executed a SELECT INTO statement and no rows were returned. You referenced an uninitialized row in a table. You read past the end of file with the UTL_FILE package. TOO_MANY_ROWS ORA-01422 You tried to execute a SELECT INTO statement and more than one row was returned. ZERO_DIVIDE ORA-01476 You tried to divide a number by zero. INVALID_NUMBER ORA-01722 You tried to execute a SQL statement that tried to convert a string to a number, but it was unsuccessful. STORAGE_ERROR ORA-06500 You ran out of memory or memory was corrupted. PROGRAM_ERROR ORA-06501 This is a generic "Contact Oracle support" message because an internal problem was encountered. VALUE_ERROR ORA-06502 You tried to perform an operation and there was a error on a conversion, truncation, or invalid constraining of numeric or character data. CURSOR_ALREADY_OPEN ORA-06511 You tried to open a cursor that is already open. Linkedin: https://www.linkedin.com/in/aditya-kumar-roy-b3673368/ Facebook: https://www.facebook.com/SpecializeAutomation/
oracle pl sql lec 21(5) :old and :new pseudorecord in hindi
 
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http://www.bitsinfotec.in/ Hey guys in this lecture i have taught about :old and :new pseudorecord in plsql in hindi. Pl sql for referencing old record and referencing new record using :old and :new pseudorecord.
Views: 136 JavaTreePoint
Ref cursor query as source  in Oracle Reports 10G
 
09:58
Oracle Reports 10G
Views: 113 maha zaman
SQL Server 12 - Referential Integrity
 
05:15
The concept of referential integrity is protecting relationships in our database. As a reminder, a relationship is when we have a foreign key reference another column. This column is usually the primary key of another table. This is a foreign key connection. If by any chance we establish a database structure where a table references another table, but we don't enforce this any way, the data in the table that is being referenced could be deleted, but the reference would still exist. If this happened, we would be breaking our referential integrity. We protect this by using referential constraints. A referential constraint tells the database that there is a connection between the two columns. This will allow you to configure what happens when the table being referenced gets updated or deleted. Another important thing to protecting referential integrity it to design the database in the correct way. This requires in depth knowledge of different types of relationships. How do you know when you need to put things in separate tables? We discussed all of the relationship possibilities in previous videos. In summary, relationships are not just something we assume… They are objectively defined so that the database knows they exists. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Support me! http://www.patreon.com/calebcurry Subscribe to my newsletter: http://bit.ly/JoinCCNewsletter Donate!: http://bit.ly/DonateCTVM2. ~~~~~~~~~~~~~~~Additional Links~~~~~~~~~~~~~~~ More content: http://CalebCurry.com Facebook: http://www.facebook.com/CalebTheVideoMaker Google+: https://plus.google.com/+CalebTheVideoMaker2 Twitter: http://twitter.com/calebCurry Amazing Web Hosting - http://bit.ly/ccbluehost (The best web hosting for a cheap price!)
Views: 11185 Caleb Curry
How to create Sequence for a table column dynamically  in ADF
 
07:43
Implementing Sequence in Adf Application
Views: 2287 Venky P
Foreign key in sql with example (create table with foreign key)
 
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desc customers -- table structure create table loan_request ( loan_requset_id int not null primary key, customer_id references customers(customer_id), loan_amount int, loan_type_id int ); insert into loan_request values(1,3,100,1); select * from loan_request ---------------------------------------------- SQL - ORACLE ----------- CUSTOMERS table is created with customer_id as primary key and customer_name columns Now to create a loan_request table with customer_id column referencing CUSTOMERS table customer_id, customer_id int references customers(customer_id) -- now lets see data in customers table -- insert values into loan_request_table -- 1 and 2 customer_id is present in the customers table -- lets try to insert the values not present in the customers table It is thrwoing error as 3 customer_id is not present in the customers table as the customer_id in the loan_request table is referring the customer_id in the customers table.
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Could not drop object because it is referenced by a FOREIGN KEY constraint - SQL Server P74
 
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SQL Server / T-SQL Tutorial Scenario: You are working as SQL Server DBA or Developer, You need to drop a table from a database. When you execute drop table SchemaName.TableName statement, you get below error. Msg 3726, Level 16, State 1, Line 12 Could not drop object 'SchemaName.TableName' because it is referenced by a FOREIGN KEY constraint. Now we know that the table is referenced by Foreign Key Constraint. The problem is how to find which table has that Foreign Key Constraint that is referencing to this table. Link to scripts used in SQL Server / TSQL Tutorial Video http://www.techbrothersit.com/2016/04/could-not-drop-object-because-it-is.html Check out our website for Different SQL Server, MSBI tutorials and interview questions such as SQL Server Reporting Services(SSRS) Tutorial SQL Server Integration Services(SSIS) Tutorial SQL Server DBA Tutorial SQL Server / TSQL Tutorial ( Beginner to Advance) http://www.techbrothersit.com/
Views: 2831 TechBrothersIT