SQL中TRUNCATE和DELETE的区别是什么?
如果你的答案是针对特定平台的,请注明。
SQL中TRUNCATE和DELETE的区别是什么?
如果你的答案是针对特定平台的,请注明。
当前回答
一眨眼的功夫就不能做DDL。
其他回答
DROP The DROP command removes a table from the database. All the tables' rows, indexes and privileges will also be removed. No DML triggers will be fired. The operation cannot be rolled back. TRUNCATE TRUNCATE removes all rows from a table. The operation cannot be rolled back and no triggers will be fired. As such, TRUNCATE is faster and doesn't use as much undo space as a DELETE. Table level lock will be added when Truncating. DELETE The DELETE command 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. Row level lock will be added when deleting.
来自:http://www.orafaq.com/faq/difference_between_truncate_delete_and_drop_commands
SQL server中删除与截断的总结 完整文章请点击这个链接:http://codaffection.com/sql-server-article/delete-vs-truncate-in-sql-server/
摘自dotnet mob文章:删除Vs截断SQL Server
TRUNCATE是DDL语句,而DELETE是DML语句。以下是两者的区别:
As TRUNCATE is a DDL (Data definition language) statement it does not require a commit to make the changes permanent. And this is the reason why rows deleted by truncate could not be rollbacked. On the other hand DELETE is a DML (Data manipulation language) statement hence requires explicit commit to make its effect permanent. TRUNCATE always removes all the rows from a table, leaving the table empty and the table structure intact whereas DELETE may remove conditionally if the where clause is used. The rows deleted by TRUNCATE TABLE statement cannot be restored and you can not specify the where clause in the TRUNCATE statement. TRUNCATE statements does not fire triggers as opposed of on delete trigger on DELETE statement
这里有一个非常好的与主题相关的链接。
并不是说截断不记录SQL Server中的任何内容。truncate不记录任何信息,但它记录您触发truncate的表的数据页的释放。
如果在开始时定义事务,则可以回滚被截断的记录,回滚后可以恢复被截断的记录。但不能在提交截断事务后从事务日志备份中恢复截断记录。
微软sql server的另一个不同之处在于,使用delete,你可以使用output语句来跟踪哪些记录被删除了,例如:
delete from [SomeTable]
output deleted.Id, deleted.Name
你不能用truncate这样做。