The difference between DELETE and TRUNCATE

Categories: Database; Tagged with: ; @ August 21st, 2012 13:29

DELETE

DML(Data Manipulation Language), is used to remove rows from a table. A WHERE clause can be used to only remove some rows. If no WHERE condition is specified, all rows will be removed. After performing a DELETE operation you need to COMMIT or ROLLBACK the transaction to make the change permanent or to undo it. Note that this operation will cause all DELETE triggers on the table to fire.

If you delect one table’s data, the ID will continue in SQL 2005,.

TRUNCATE

DDL(Data Definition Language), TRUNCATE removes all rows from a table. The operation cannot be rolled back and no triggers will be fired. As such, TRUCATE is faster and doesn’t use as much undo space as a DELETE.

If you truncate one table, the ID will be reset in SQL 2005.

Auto Format SQL Scripts tools: online/desktop app/plugin

Categories: Database; Tagged with: ; @ August 15th, 2012 12:33

Online tool: http://www.dpriver.com/pp/sqlformat.htm

Really easy and fast!

There is a desktop version of this sql formatter, the desktop version has more features, and it’s faster and earier to use. There is also an Add-On version for Visual Studio and an Add-On for SQL Server Management Studio.

 

Nested select statement in SQL Server 使用嵌套查询

Categories: Database; Tagged with: ; @ August 7th, 2012 11:19

In SQL Server, we need to alias the subquery, otherwise there will be syntax error.

SELECT name FROM (SELECT name FROM users) // Incorrect syntax near ‘)’
SELECT uTable.name FROM (SELECT name FROM users) uTable

 

 

Generate database diagrams using MS SQL Server 2008

Categories: Database; Tagged with: ; @ August 3rd, 2012 12:24

Generate database diagrams using MS SQL Server 2008

Open SQL Server Management Studio,
and explorer the databases, expand the database, and right click on the ‘Database Diagrams‘,
click ‘Create new diagram’, select the tables, and the diagrams will be generated.

see more: http://www.onlinehowto.net/create-database-diagrams-using-ms-sql-server-2008/1563

SQL Server get/list all tables in the database

Categories: Database; Tagged with: ; @ July 31st, 2012 15:16

SQL Server – 2008 get all tables:

USE database
SELECT * FROM SYS.TABLES ORDER BY NAME;

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