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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: 13264 Caleb Curry
SQL tutorials 20: On Delete Cascade Foreign Key By Manish Sharma (RebellionRider)
 
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Oracle Database 11g Tutorial 20: On delete cascade This tutorial will show you how to define foreign key with on delete cascade clause. Links Blog: http://www.rebellionrider.com/on-delete-cascade.htm SQL Tutorial 19 On delete set Null: http://www.rebellionrider.com/on-delete-cascade.htm SQL Tutorial 19 Foreign Key: http://youtu.be/0nbkBI5r3Gw Copy Cloud referral link || Use this link to join copy cloud and get 20GB of free storage https://copy.com?r=j7eYO7 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. 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: 43993 Manish Sharma
113. ON DELETE CASCADE in SQL (Hindi)
 
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Views: 7317 Geeky Shows
ON DELETE CLAUSE OF FOREIGN KEY CONSTRAINT IN ORACLE SQL WITH EXAMPLE (CASCADE/SET NULL/NO ACTION)
 
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This is a free video tutorial explaining about the nonmandatory on delete clause in the foreign key constraint in Oracle SQL database, the video explains about how the on delete set null and on delete cascade works, how it can be implemented with easy to understand examples. We have also shown practical demonstration on creating the foreign key constraint, and then deleting the data from the parent table and observing the changes that take place in the child table.
Views: 1249 Kishan Mashru
MySQL 17 - ON DELETE and ON UPDATE
 
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Now, what happens when you have successfully created a reference, and now you try deleting the parent? This is where the ON DELETE clause come in. This is essentially how we configure how strict a foreign key is. There are 3 options you can give for an ON DELETE: RESTRICT / NO ACTION Yes - In MySQL they are the same, but not all DBMS. CASCADE Yes SET NULL Yes Now the default is RESTRICT. This means that when you try to delete a parent row, MySQL is going to throw an error and not let you. Cascade means that if you delete the parent row, any rows that reference that parent will also be deleted. This is pretty dangerous and not often recommended. SET NULL will set the foreign key to be NULL. Now obviously, this is going to require that the foreign key is not labelled NOT NULL. In addition to the ON DELETE clause, there is the ON UPDATE clause. This one is a little less common because it configures what happens when a parent value changes. Obviously, when you are referencing a primary key, the ON UPDATE clause is nearly useless. That's because the primary key value is never supposed to change. If, on the other hand, we have a foreign key referencing a UNIQUE column that is not a primary key, it may change occasionally. So the only times you have to worry about the ON UPDATE clause is with foreign keys referencing UNIQUE columns that are not a primary key, and when you have natural keys that break the rules and actually do change at some point in time. The ON UPDATE clause has the same options as the ON DELETE clause and they all work the same way. Now, the last thing you need to know about foreign keys is that they must match the data type of the column you are referencing. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 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: 12750 Caleb Curry
SQL tutorial 19: ON DELETE SET NULL clause of Foreign Key By Manish Sharma (RebellionRider)
 
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SQL Tutorial 19 : ON DELETE SET NULL foreign key Clause. Links used in the tutorial On delete set null website article [ download SQL script from same link] : http://www.rebellionrider.com/on-delete-set-null.htm Foreign Key Tutorial Video : http://youtu.be/0nbkBI5r3Gw Foreign Key Tutorial Blog : http://www.rebellionrider.com/sql-foreign-key.htm This video is the part of foreign key video In this sql tutorial you will learn the referential clause ON DELETE SET NULL of foreign key. On Delete Set null clause guarantee the relation integrity in foreign key/ 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: 47135 Manish Sharma
114. ON DELETE SET NULL in SQL (Hindi)
 
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Views: 3822 Geeky Shows
Основы SQL. Каскадное удаление данных в базах данных и языке SQL SQLite: ON DELETE CASCADE
 
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В этом видео мы посмотрим для чего нужно и как реализуется каскадное удаление данных в языке SQL и реляционных базах данных на примере библиотеки SQLite. Каскадное удаление реализуется правилом/ограничением ON DELETE CASCADE. Рубрика SQLite на сайте: http://zametkinapolyah.ru/zametki-o-mysql/sqlite/ Текстовая версия: http://zametkinapolyah.ru/zametki-o-mysql/kaskadnoe-udaleniya-dannyx-v-bazax-dannyx-sqlite.html Паблик блога в ВК: https://vk.com/zametkinapolyah Тематическая группа в ВК: https://vk.com/zametki_bd Помощь проекту: WMR: R28827266698 WMZ: Z293550531456 Яндекс.Деньги: 410011531129223
SQL Cascade Delete Details
 
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Views: 1990 Mike Perel
SQL CASCADE, SET DEFAULT, NO ACTION
 
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Jamie King of Neumont University showing the differences between CASCADE, SET DEFAULT, NO ACTION with foreign keys.
Views: 10832 Jamie King
TUTORIAL-1 Create, insert, delete, drop  operations in sql developer oracle 12c with subtitles
 
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first see the syntax 1)CREATE TABLE tablename(fields and its data type) 2)INSERT INTO tablename VALUES(values with same data type) 3)DELETE FROM tablename WHERE condition 4)DROP TABLE tablename
Views: 3600 Let's Learn Pro
SQL DELETE vs TRUNCATE
 
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http://zerotoprotraining.com This video explains, SQL DELETE vs TRUNCATE Category: Oracle SQL Tags: DELETE, TRUNCATE
Views: 13424 HandsonERP
Difference between Delete and Truncate and Drop in Oracle Sql
 
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This is a free tutorial on understanding difference between drop, delete and truncate statements. I have tried to cover most of the major difference between all these three statements and have also shown the same with simple and easy to understand examples. Hope it will be helpful to all. If you want more such videos of exciting and amazing 'difference between' concepts, check out the links below : union and union all : https://youtu.be/n9FqQOd8liY char and varchar2 : https://youtu.be/039qzwjWf4k replace and translate : https://youtu.be/HKYF77BGzOE procedure and function : https://youtu.be/q3LmOenL120 in and exists : https://youtu.be/REX4IjRYlFw rank and dense_rank : https://youtu.be/WGSX998hZ9M %type and %rowtype : https://youtu.be/MlLUFeZ_3eM
Views: 1595 Kishan Mashru
117. ON UPDATE CASCADE in SQL (Hindi)
 
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Views: 4405 Geeky Shows
Oracle - SQL - Delete Statement
 
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Oracle - SQL - Delete Statement Watch more Videos at https://www.tutorialspoint.com/videotutorials/index.htm Lecture By: Mr. Anadi Sharma, Tutorials Point India Private Limited.
SQL with Oracle 10g XE - Using DELETE to Remove a Row from a Table
 
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In this video I use the DELETE command to remove an entire row from a table. When using the DELETE command be sure to use the keywords FROM and WHERE to choose the table and record you wish to delete. The code I used is: DELETE FROM BOOKS WHERE BOOK_ID = '11'; This video is part of a series of videos with the purpose of learning the SQL language. For more information visit Lecture Snippets at http://lecturesnippets.com.
Views: 8973 Lecture Snippets
OracleSQL#13 How to delete row in oracle database|  SQL delete Statement
 
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In this video, I am explaining, How to delete a table from the database using SQL developer In this series we cover the following topics: SQL basics, create table oracle, SQL functions, SQL queries, SQL server, SQL developer installation, Oracle database installation, SQL Statement, OCA, Data Types, Types of data types, SQL Logical Operator, SQL Function,Join- Inner Join, Outer join, right outer join, left outer join, full outer join, self-join, cross join, View, SubQuery, Set Operator. follow me on: Facebook Page: https://www.facebook.com/LrnWthr-319371861902642/?ref=bookmarks Contacts Email: [email protected] Instagram: https://www.instagram.com/lrnwthr/ Twitter: https://twitter.com/LrnWthR
Views: 62 EqualConnect Coach
PL/SQL tutorial 25: How To Uninstall Oracle Database 11g From Windows 10 64 bit
 
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Learn How To properly Uninstall Oracle Database 11g From Windows 10 64 bit manually without formatting your computer By Manish Sharma at RebellionRider.com Path For Start Menu Entry C:\ProgramData\Microsoft\Windows\Start Menu\Programs ------------------------------------------------------------------------ ►►►LINKS◄◄◄ Blog : http://bit.ly/uninstall-oracle-11g-from-win-10 How To Write Killer LinkedIn Summary http://bit.ly/write-killer-linkedin-summary Previous Tutorial ► How To Install 11g on windows 10: https://youtu.be/d_CyuCLC3Ls ► How To Install 12c On Windows 10: https://youtu.be/vAUNgaYJSw0 ------------------------------------------------------------------------- ►►►Let's Get Free Uber Cab◄◄◄ Use Referral Code UberRebellionRider and get $20 free for your first ride. ------------------------------------------------------------------------- ►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 https://www.facebook.com/imthebhardwaj http://instagram.com/rebellionrider https://plus.google.com/+Rebellionrider http://in.linkedin.com/in/mannbhardwaj/ http://rebellionrider.tumblr.com/ http://www.pinterest.com/rebellionrider/ ___Facebook Official Page___ https://www.facebook.com/RebellionRider.official/ You can also Email me at for E-mail address please check 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: 74152 Manish Sharma
SQL: Delete Vs Truncate Vs Drop
 
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In this tutorial, you'll learn the difference between delete/drop and truncate. PL/SQL (Procedural Language/Structured Query Language) is Oracle Corporation's procedural extension for SQL and the Oracle relational database. PL/SQL is available in Oracle Database (since version 7), TimesTen in-memory database (since version 11.2.1), and IBM DB2 (since version 9.7).[1] Oracle Corporation usually extends PL/SQL functionality with each successive release of the Oracle Database. PL/SQL includes procedural language elements such as conditions and loops. It allows declaration of constants and variables, procedures and functions, types and variables of those types, and triggers. It can handle exceptions (runtime errors). Arrays are supported involving the use of PL/SQL collections. Implementations from version 8 of Oracle Database onwards have included features associated with object-orientation. One can create PL/SQL units such as procedures, functions, packages, types, and triggers, which are stored in the database for reuse by applications that use any of the Oracle Database programmatic interfaces. PL/SQL works analogously to the embedded procedural languages associated with other relational databases. For example, Sybase ASE and Microsoft SQL Server have Transact-SQL, PostgreSQL has PL/pgSQL (which emulates PL/SQL to an extent), and IBM DB2 includes SQL Procedural Language,[2] which conforms to the ISO SQL’s SQL/PSM standard. The designers of PL/SQL modeled its syntax on that of Ada. Both Ada and PL/SQL have Pascal as a common ancestor, and so PL/SQL also resembles Pascal in several aspects. However, the structure of a PL/SQL package does not resemble the basic Object Pascal program structure as implemented by a Borland Delphi or Free Pascal unit. Programmers can define public and private global data-types, constants and static variables in a PL/SQL package.[3] PL/SQL also allows for the definition of classes and instantiating these as objects in PL/SQL code. This resembles usage in object-oriented programming languages like Object Pascal, C++ and Java. PL/SQL refers to a class as an "Abstract Data Type" (ADT) or "User Defined Type" (UDT), and defines it as an Oracle SQL data-type as opposed to a PL/SQL user-defined type, allowing its use in both the Oracle SQL Engine and the Oracle PL/SQL engine. The constructor and methods of an Abstract Data Type are written in PL/SQL. The resulting Abstract Data Type can operate as an object class in PL/SQL. Such objects can also persist as column values in Oracle database tables. PL/SQL is fundamentally distinct from Transact-SQL, despite superficial similarities. Porting code from one to the other usually involves non-trivial work, not only due to the differences in the feature sets of the two languages,[4] but also due to the very significant differences in the way Oracle and SQL Server deal with concurrency and locking. There are software tools available that claim to facilitate porting including Oracle Translation Scratch Editor,[5] CEITON MSSQL/Oracle Compiler [6] and SwisSQL.[7] The StepSqlite product is a PL/SQL compiler for the popular small database SQLite. PL/SQL Program Unit A PL/SQL program unit is one of the following: PL/SQL anonymous block, procedure, function, package specification, package body, trigger, type specification, type body, library. Program units are the PL/SQL source code that is compiled, developed and ultimately executed on the database. The basic unit of a PL/SQL source program is the block, which groups together related declarations and statements. A PL/SQL block is defined by the keywords DECLARE, BEGIN, EXCEPTION, and END. These keywords divide the block into a declarative part, an executable part, and an exception-handling part. The declaration section is optional and may be used to define and initialize constants and variables. If a variable is not initialized then it defaults to NULL value. The optional exception-handling part is used to handle run time errors. Only the executable part is required. A block can have a label. Package Packages are groups of conceptually linked functions, procedures, variables, PL/SQL table and record TYPE statements, constants, cursors etc. The use of packages promotes re-use of code. Packages are composed of the package specification and an optional package body. The specification is the interface to the application; it declares the types, variables, constants, exceptions, cursors, and subprograms available. The body fully defines cursors and subprograms, and so implements the specification. Two advantages of packages are: Modular approach, encapsulation/hiding of business logic, security, performance improvement, re-usability. They support object-oriented programming features like function overloading and encapsulation. Using package variables one can declare session level (scoped) variables, since variables declared in the package specification have a session scope.
Views: 59466 radhikaravikumar
SQL Delete Statement with Example on Oracle 11g Database
 
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SQL Lecturers for Beginners in Hindi and English SQL Delete Statement with Example on Oracle 11g Database
ORACLE SQL INTERVIEW QUESTION : DIFFERENCE BETWEEN DELETE AND TRUNCATE
 
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This video tutorial is on frequently asked interview question like the difference between delete and truncate statement in oracle sql, after watching this video you will understand more on the difference between both the statements and will be able to answer this interview question with a lot of confidence. Link to know more on HVM in oracle please refer to the link : https://youtu.be/uZ9BwzZx6lI
Views: 4245 Kishan Mashru
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: 18860 Caleb Curry
Part 4   Delete duplicate rows in sql
 
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Link for all dot net and sql server video tutorial playlists http://www.youtube.com/user/kudvenkat/playlists Link for slides, code samples and text version of the video http://csharp-video-tutorials.blogspot.com/2014/05/part-4-delete-duplicate-rows-in-sql.html In this video, we will discuss deleting all duplicate rows except one from a sql server table. SQL Script to create Employees table Create table Employees ( ID int, FirstName nvarchar(50), LastName nvarchar(50), Gender nvarchar(50), Salary int ) GO Insert into Employees values (1, 'Mark', 'Hastings', 'Male', 60000) Insert into Employees values (1, 'Mark', 'Hastings', 'Male', 60000) Insert into Employees values (1, 'Mark', 'Hastings', 'Male', 60000) Insert into Employees values (2, 'Mary', 'Lambeth', 'Female', 30000) Insert into Employees values (2, 'Mary', 'Lambeth', 'Female', 30000) Insert into Employees values (3, 'Ben', 'Hoskins', 'Male', 70000) Insert into Employees values (3, 'Ben', 'Hoskins', 'Male', 70000) Insert into Employees values (3, 'Ben', 'Hoskins', 'Male', 70000) The delete query should delete all duplicate rows except one. Here is the SQL query that does the job. PARTITION BY divides the query result set into partitions. WITH EmployeesCTE AS ( SELECT *, ROW_NUMBER()OVER(PARTITION BY ID ORDER BY ID) AS RowNumber FROM Employees ) DELETE FROM EmployeesCTE WHERE RowNumber ] 1
Views: 313414 kudvenkat
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: 9463 Caleb Curry
PL/SQL tutorial 15: DML Trigger With Before Insert, Update and Delete DML Examples
 
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PL/SQL Tutorial 15 explaining DML Trigger with examples such as Before Insert, Update and Delete in Detail. ------------------------------------------------------------------------ ►►►LINKS◄◄◄ Blog : http://bit.ly/dml-triggers Previous Tutorial ► Trigger Intro : https://youtu.be/R3fvX_xf5P4 ► SELECT-INTO : https://youtu.be/F5eMJhwmCQs ►IF-THEN-ELSIF: https://youtu.be/aW9XgUHSr0I ------------------------------------------------------------------------- ►►►Let's Get Free Uber Cab◄◄◄ Use Referral Code UberRebellionRider and get $20 free for your first ride. ------------------------------------------------------------------------- ►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 https://www.facebook.com/imthebhardwaj http://instagram.com/rebellionrider https://plus.google.com/+Rebellionrider http://in.linkedin.com/in/mannbhardwaj/ http://rebellionrider.tumblr.com/ http://www.pinterest.com/rebellionrider/ You can also Email me at for E-mail address please check 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: 95527 Manish Sharma
SQL in Oracle 11g Tutorial #7: Alter table( Add, Delete , Enable and Disable Primary Key)
 
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SQL in Oracle 11g Tutorial #7: Alter table( Add, Delete , Enable and Disable Primary Key). This video will explain you the following: 1. How to Add the Primary Key 2. How to delete the primary Key 3. How to Enable the Primary Key 4. How to disable the primary key Thanks for Watching my Channel “Learn TechToTech”. Please subscribe my channel for getting first updates after uploading video.Social Media pages of Channel are: 1. My Website : www.learnfromrakesh.com 2. My Twitter: https://twitter.com/LearnTechtotech 3. Facebook Page: https://www.facebook.com/LearnTechToTech 4. Blogger : https://learntechtotech.blogspot.in/ 5. Google+ : https://learntechtotech.blogspot.in/ 6. Pinterest : https://in.pinterest.com/LearnTechToTech/ 7. LinkedIn: https://www.linkedin.com/in/Learntechtotech/ Playlist of Different Technology: 1. Operating System : https://goo.gl/q6SfrW 2. Python Programming Language : https://goo.gl/L8b5dc 3. C Language : https://goo.gl/SwvDu9 4. C language for Placement: https://goo.gl/AaQBa4 5. Java: https://goo.gl/M8F2uy 6. MySql : https://goo.gl/vdJbHQ 7. Android Mobile Application Development: https://goo.gl/M6woaT 8. Kotlin Programming Language : https://goo.gl/GXE5cd 9. Go Programming: https://goo.gl/Ua3xYW 10. Internet of Things(IoT): https://goo.gl/f2afkY 11. Oracle 11g : https://goo.gl/zds8r2 12. C++ : https://goo.gl/C1psMT
Views: 304 Learn TechToTech
Oracle - SQL - Creating Sequences
 
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Oracle - SQL - Creating Sequences Watch more Videos at https://www.tutorialspoint.com/videotutorials/index.htm Lecture By: Mr. Anadi Sharma, Tutorials Point India Private Limited.
Oracle SQL Tutorial 21 - How to Create / Drop Indexes
 
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In the last video, we wrote up the SQL to create three tables: CREATE TABLE users( user_id NUMBER, username VARCHAR2(50 CHAR) UNIQUE, CONSTRAINT users_pk PRIMARY KEY (user_id) ); 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 ); 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) ); I'm going to increase the size of the users table a bit by adding a first and last name column. CREATE TABLE users( user_id NUMBER, username VARCHAR2(50 CHAR) UNIQUE, first_name VARCHAR2(50 CHAR), last_name VARCHAR2 (50 CHAR), CONSTRAINT users_pk PRIMARY KEY (user_id) ); But before we finish this design, we should consider indexing certain columns. What columns should we index? Well, as a reminder, the columns that are indexed by default are columns with the UNIQUE constraint, and those that are labeled as primary keys. Columns that are not indexed but often should be are those labeled as a foreign key. The column that jumps out the most to me is the creator column of the project table. It's the only foreign key that is not part of some index. Let's fix this by creating our first index. The way we do that is with the CREATE INDEX command. CREATE INDEX projects_creator_ix ON projects (creator) What naming convention are we following for the index? We are naming it by the table name, followed by an underscore, followed by the column, followed by an underscore, followed by an ix (for index). In this situation it does not apply, but if our foreign key column is labeled as UNIQUE, we can add the UNIQUE keyword like this: CREATE UNIQUE INDEX projects_creator_ix ON projects (creator) Now if you want to get rid of an INDEX, you can use this command: DROP INDEX projects_creator_ix Now, if we want to select data from the user table and the project table we can do that much faster. That's because the foreign key and column it references are both indexed and those are the columns we would do the join on. We will discuss how to do joins in a future video. So what are some potential problems with this database design? Overall, it is pretty good. With this design though we need to make sure there is no way for someone to update a user's username. In the next video we are going to discuss why. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 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: 7605 Caleb Curry
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: 12885 Caleb Curry
SQL Server 17 - ON DELETE and ON UPDATE
 
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Now, what happens when you have successfully created a reference, and now you try deleting the parent? This is where the ON DELETE clause comes in. This is essentially how we configure how strict a foreign key is. There are 4 options you can give for an ON DELETE: Standard SQL Server NO ACTION Yes (Default) CASCADE Yes SET NULL Yes SET DEFAULT Yes Now the default is NO ACTION. This means that when you try to delete a parent row, SQL Server is going to throw an error and not let you. Cascade means that if you delete the parent row, any rows that reference that parent will also be deleted. This is pretty dangerous and not often recommended. SET NULL will set the foreign key to be NULL. Now obviously, this is going to require that the foreign key is not labelled NOT NULL. Finally, set DEFAULT will change the reference to the child row to some default value. We have not discussed defaults, but a column can have a default value. For example, we could make a deleted user in our Users table, and set the default for the foreign key to be the deleted user, and when any other users are deleted it will default to the deleted user UserId. In addition to the ON DELETE clause, there is the ON UPDATE clause. This one is a little less common because it configures what happens when a parent value changes. Obviously, when you are referencing a primary key, the ON UPDATE clause is nearly useless. That's because the primary key value is never supposed to change. If, on the other hand, we have a foreign key referencing a UNIQUE column that is not a primary key, it may change occasionally. So the only times you have to worry about the ON UPDATE clause is with foreign keys referencing UNIQUE columns that are not a primary key, and when you have natural keys that break the rules and actually do change at some point in time. The ON UPDATE clause has the same options as the ON DELETE clause and they all work the same way. Now, the last thing you need to know about foreign keys is that they must match the data type of the column you are referencing. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 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: 4310 Caleb Curry
Oracle - SQL - Foreign Key Constraint
 
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Oracle - SQL - Foreign Key Constraint Watch more Videos at https://www.tutorialspoint.com/videotutorials/index.htm Lecture By: Mr. Anadi Sharma, Tutorials Point India Private Limited.
115. ON DELETE NO ACTION or ON UPDATE RESTRICT in SQL (Hindi)
 
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Please Subscribe Channel Like, Share and Comment Visit : www.geekyshows.com
Views: 4229 Geeky Shows
PL/SQL tutorial 64: PL/SQL Collection Method Delete in Oracle Database by Manish Sharma
 
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------------------------------------------------------------------------ ►►►LINKS◄◄◄ Blog: http://bit.ly/delete-procedure Previous Tutorial ► Collection method Next & Prior https://youtu.be/5Ya35KboF1A ------------------------------------------------------------------------- ►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: 4648 Manish Sharma
How TO DELETE ROW, MODIFY, UPDATE COLUMN, DROP TABLE in Oracle SQL Using Cmd [Hindi/Urdu].
 
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Hi Friends !!!!! In this Video we show the How to delete table, row, update etc. Oracle Databse- a) Open The Sqlplus. b) Connect The Workspace. c) Show Your Tables. Query : Select * from tab; d) Select the table where you want to delete row. Query : Delete From [Table Name] Where id=?; e) Show Your Tables. Query : Select * from tab; 1 row delete sucessfully. f) If You Modify Your Table to follow this Query : Alter table [Table Name] modify [Column Name] varchar2(10); Your table column is modified. g) If You Update row data follow this Query Update [Table Name] set [Column Name]='row data of column' where id=?; If you delete the table follow the Query : Drop Table [Table Name]; Your table is deleted sucessfully. Related video Links : How to Install Java Netbeans IDE in Windows 7, 8.1, 10 [Hindi/Urdu]: https://youtu.be/jOYMNognZXM How To Install Java On Window 10, 8.1, 7 64 bit Operating System [Hindi/Urdu] : https://youtu.be/y2-g09nY33A How to install Windows 7, 8.1,10 from a flash drive or Pandrive . [Hindi/Urdu] : https://youtu.be/s4kNcirxWrc How to Make Bootable Your Pandrive [Hindi/Urdu] : https://youtu.be/BPx_Ua_aCfY How to install Oracle 11G XE On Windows 10, 8.1, 7 Operating System in [Hindi/Urdu] : https://youtu.be/-2k4QCIpIOs How to Create Table Oracle Datbase Using Sqlplus [Hindi/Urdu] : https://youtu.be/EHnAebRP6Yw How To Insert Table Oracle Database Using Sqlplus [Hindi/Urdu]: https://youtu.be/Fu0tlCml8F8 How TO DELETE ROW, MODIFY, UPDATE COLUMN, DROP TABLE in Oracle SQL Using Cmd [Hindi/Urdu]: https://youtu.be/prz9Pr0PFEg How to recover format or delete Pandrive, Sdcard, Memory Card Or Harddisk Data [Hindi/Urdu] : https://youtu.be/0GGDHVTxDh0 How to install Oracle SQl Developer And How to Connect Your Database Sql Developer[Hindi/Urdu] : https://youtu.be/608nx3mT10c How to use SQL Distinct Keyword in Cmd Or Oracle SQL Developer [Hindi/Urdu] : https://youtu.be/ofLLZ9-EG_E How to use SQL AND Or OR operator [Hindi/Urdu] : https://youtu.be/zzqDp7U3rC8 How To Use SQL Where Operation using CMD [Hindi/Urdu] : https://youtu.be/EHmL0Wa14UY How To Use SQL ASC and DESC Operation using cmd [Hindi/Urdu] : https://youtu.be/UI0hat_RMX0 For Any Query Email Add : [email protected] Facebook Page link : https://www.facebook.com/Technical-Education-4-You-144220269545756/?ref=nf&hc_ref=ART3p2EX_iIdZHm96Uz36P99q7xfycGfo54RJafY-f0O4n1bdvWU_5xGHpPrOpLepi4
SQL tutorials 18: SQL Foreign Key Constraint
 
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SQL Tutorial 18: SQL foreign key constraint. Topic covered in this tutorial 1. Defining SQL foreign key using create table at column level 2. Defining SQL foreign key using create table at table level 1. Defining SQL foreign key using Alter Table statement Links Website article: http://www.rebellionrider.com/sql-foreign-key.htm Primary key tutorial: http://www.rebellionrider.com/sql-foreign-key.htm Create Table Tutorial: http://www.rebellionrider.com/sql-create-table.html 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 linking, commenting, sharing and watching more of our videos This is Manish from RebellionRider.com Foreign key is an Input/output data constraint which is also known as referential integrity constraint. Foreign key represent a link or say a relationship between columns of tables. Similar to primary key constraint Foreign Key constraint is also of two types. Simple Foreign key constraint and Composite Foreign key constraint. Constraint which involves only one column in foreign key in child table and one column in reference key in parent table is called Simple Foreign Key. While the constraint which involves more than one column in foreign key in child table and more than one column in reference key in the parent table is called Composite Foreign Key.
Views: 99041 Manish Sharma
SQL tutorials 17: SQL Primary Key constraint,  Drop primary Key
 
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Blog link: http://www.rebellionrider.com/sql-primary-key.htm SQL tutorial on Primary key / SQL Primary key, In this tutorial you will learn about simple primary key, composute primary key, how to drop primary key. defining primary key using create table and alter table along with many other things. 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 linking, commenting, sharing and watching more of our videos This is Manish from RebellionRider.com So Primary Key There are two types of Primary keys First is Simple primary Key: Primary key which Involves only one column and Second is Composite Primary Key: Primary Key which involves more than one column. We will start with Simple primary key. You can create Primary key either with Create Table statement of by using Alter table Statement. Let's define simple primary key using create table statements. With create table statement we can either define primary key at column level or at table level. We will start with defining Primary key at column level using create table statement. You just have to put keyword Primary key after data type and size of column while defining a column of a table. Here oracle server will create a primary key on product id with default constraint name which will be slightly difficult to understand. You can give your own name to your constraint which is also a good practice.
Views: 96996 Manish Sharma
Merge Statement in Oracle SQL with Example (UPDATE/DELETE or INSERT)
 
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This video demonstrates how to write a Merge Statement in oracle sql, how it is useful in doing a conditional update or delete or both of them when the condition between the target table and source table is evaluated to true, and how we can insert the record into the target table when condition is evaluated to false. The video also shows the use of UPDATE, DELETE and INSERT with Merge, and also the various possible ways to use a Merge statement!!!
Views: 7599 Kishan Mashru
TUTORIAL-2 Select, Create, Alter, Insert, Update, Delete operations sql developer oracle 12c
 
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This is SQL tutorial video for beginners. I have used Oracle 12c for its implementation. If you don't have oracle 12c downlad it from Oracle official website. It is open source, you don't need to pay for it. and Watch how to install Oracle 12c here:-https://www.youtube.com/watch?v=DXh-hmDb0xE&t=5s 1. create table tablename 2.insert into tablename values(); 3.Alter table add field datatype 4.Delete from tablename where conditions 5.UPDATE tablename SET values where condition If you have any doubt, Please comment below and share it because sharing is caring!! Have a great programming!!
Views: 3890 Let's Learn Pro
SQL Tutorial : How To Delete Duplicate Records in SQL Oracle
 
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SQL Tutorial : How To Delete Duplicate Records in SQL Oracle SQL Tutorial SQL Tutorial for beginners PLSQL Tutorial PLSQL Tutorial for beginners PL/SQL Tutorial PL SQL Tutorial PL SQL Tutorial for beginners PL/SQL Tutorial for beginners Oracle SQL Tutorial
Views: 2529 TechLake
How to create Foreign Key Constraint with ON DELETE CASCADE in SQL Server - SQL Server Tutorial 80
 
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SQL Server / T-SQL Tutorial Scenario: You are working as SQL Server developer, you need to create two tables with Primary -Foreign Key Relationship. You want to create Foreign Key Constraint with setting if record will be deleted from Referenced Table (Primary Key Column Table), it should be deleted from Parent Table ( Foreign Key Constraint Table) as well. Link to scripts used in SQL Server / TSQL Tutorial Video http://www.techbrothersit.com/2016/04/how-to-create-foreign-key-constraint_29.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: 2850 TechBrothersIT
SQL: How-To: Delete a Column from a Table
 
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The Best Site to Learn SQL Online
Views: 7514 TechnicalSkills
Oracle PL/SQL Tutorials | Difference between DROP, TRUNCATE and DELETE | by Mr.Vaman Deshmukh
 
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Oracle PL/SQL Tutorials | Difference between DROP, TRUNCATE and DELETE | by Mr.Vaman Deshmukh Difference between TRUNCATE , DELETE and DROP in SQL Server Difference between delete truncate and drop in sql ** For Online Training Registration: https://goo.gl/r6kJbB ► Call: +91-8179191999 ► Visit Our Website for Classroom Training: https://nareshit.in ► For Online Training: https://nareshit.com/ #OraclePLSQLTutorials #DifferencebetweenDROPTRUNCATEandDELETE #Tutorials -------------------------- ► About NareshIT: "Naresh IT is having 14+ years of experience in software training industry and the best Software Training Institute for online training, classroom training, weekend training, corporate training of Hadoop, Salesforce, AWS, DevOps, Spark, Data Science, Python, Tableau, RPA ,Java, C#.NET, ASP.NET, Oracle, Testing Tools, Silver light, Linq, SQL Server, Selenium, Android, iPhone, C Language, C++, PHP and Digital Marketing in USA,Hyderabad, Chennai and Vijayawada,Bangalore India which provides online training across all the locations -------------------------- ► Our Online Training Features: 1.Training with Real-Time Experts 2.Industry Specific Scenario’s 3.Flexible Timings 4.Soft Copy of Material 5. Share Videos of each and every session. -------------------------- Please write back to us at [email protected]/[email protected] or Call us at USA: +1404-232-9879 or India: +918179191999 ** Check The Below Links** ► For Course Reg: https://goo.gl/r6kJbB ► Subscribe to Our Channel: https://goo.gl/q9ozyG ► Circle us on G+: https://plus.google.com/NareshIT ► Like us on Facebook: https://www.facebook.com/NareshIT ► Follow us on Twitter: https://twitter.com/nareshitech ► Follow us on Linkedin: https://in.linkedin.com/company/naresh-i-technologies ► Follow us on Instagram: https://www.instagram.com/nareshitech/
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: 435 TechLake
Oracle SQL PLSQL 12C Tutorial 13 - DELETE Statement
 
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This Video Tutorial Will Describe how to delete a row or delete data which is already inserted into the table in oracle 12C version. This command will also work on other versions of database like Oracle 11g Database, Oracle 10g Database, Oracle 9i Database, Oracle 8i Database, Oracle 8 Database and so on. Sometimes you delete to delete some unwanted rows or data from the table. Delete command is used to do that. But it does not permanently delete rows, you can restore or rollback the deleted rows before commit. Full Syntax will be given in this video tutorial about how to insert records in oracle database table. Along with the live example to delete rows from the table. All the keywords, format, mandatory clauses etc are described in this video.
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: 10848 Caleb Curry
What are Constraints in Oracle - [ SQL Interview Question ]
 
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This is very frequently asking question in SQL - PLSQL interview. For more details about SQL and PLSQL Interview Questions answers visit my blog http://oracletemple.blogspot.in/ Please Leave your comments about this video. Useful plsql books link. http://goo.gl/XMy0tt Watch More... What is Parameterized Cursor in Oracle https://www.youtube.com/watch?v=JMKwHlVi6-A What is autonomous transaction in Oracle. https://www.youtube.com/watch?v=gyvFajpfoWE What are Constraints available in Oracle. https://www.youtube.com/watch?v=WivhdLXQklQ What is Mutation Error and How to avoid mutation. https://www.youtube.com/watch?v=CbWNCyW18Bs 5 Effective way to delete Duplicate rows https://www.youtube.com/watch?v=1wtTtnc87Oc What is Difference between Delete and Truncate https://www.youtube.com/watch?v=7b6wQ3Qumgg
Views: 6210 Ram Gupta
Before, After Insert or Update or Delete plsql trigger example.
 
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A pl sql tutorial to understand Before, After Insert or Update or Delete trigger on table. This pl sql tutorial will give you a good concept of how to write pl sql triggers. Here is one example of the trigger create or replace trigger trigger_name before insert or update or delete on table_name for each row begin if inserting then dbms_output.put_line('Before inserting on table'); elsif updating then dbms_output.put_line('Before updating on table'); elsif deleting then dbms_output.put_line('Before deleting on table'); end if; end;
Views: 28075 Subhroneel Ganguly
How to Delete Table in sql using oracle 10g or sql
 
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This video gives information about How to Delete Table in sql using oracleXE 10g
Views: 2806 AvilTwo Beginer

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