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
Truncate命令用于重新初始化表,它是一个删除表中所有行的DDL命令。DELETE是一个DML命令,用于根据某些条件删除一行或一组行,如果没有指定condition,则该命令将删除表中的所有行。
其他回答
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
它方便的一个重要原因是,当您需要刷新数百万行表中的数据,但又不想重新构建它时。“Delete *”会花费很长时间,而Truncate对性能的影响可以忽略不计。
对于SQL Server或MySQL,如果有一个带有自动递增的PK, truncate将重置计数器。
Truncate and Delete in SQL are two commands which is used to remove or delete data from table. Though quite basic in nature both Sql commands can create lot of trouble until you are familiar with details before using it. An Incorrect choice of command can result is either very slow process or can even blew up log segment, if too much data needs to be removed and log segment is not enough. That's why it's critical to know when to use truncate and delete command in SQL but before using these you should be aware of the Differences between Truncate and Delete, and based upon them, we should be able to find out when DELETE is better option for removing data or TRUNCATE should be used to purge tables.
参考资料请点击这里
删除
DELETE是一个DML命令 DELETE可以回退 Delete =仅删除-因此可以回滚 在DELETE中,可以使用WHERE子句编写条件 语法- Delete from [Table] where [Condition]
截断
TRUNCATE是一个DDL命令 不能在TRUNCATE中回滚,TRUNCATE将永久删除该记录 Truncate = Delete+Commit -这样我们就不能回滚 不能在TRUNCATE中使用条件(WHERE子句) 语法- Truncate table [table]
详情请浏览
http://www.zilckh.com/what-is-the-difference-between-truncate-and-delete/