如果有可能在sql中使用TRUNCATE删除单个实体 [英] if there any possible to delete single entity using TRUNCATE in sql

问题描述

如果有任何可能在sql中使用TRUNCATE删除单个实体

解决方案

如果用single entity表示单行则答案为No - 您不能在sql中使用Truncate来执行此操作 - 请参阅文档 [

^ ] class =op> Quote：

从表中删除 所有行而不记录单个行删除。 TRUNCATE TABLE类似于没有WHERE子句的DELETE语句;但是，TRUNCATE TABLE更快，并且使用更少的系统和事务日志资源。

如果您可以识别要删除的行，则在WHERE子句中包含这些详细信息，例如：

  DELETE   FROM  tablename  WHERE  ID = 7 

或

  DELETE   FROM  tablename 其中 column1 = '  A' 和 column2 = '  2' 

或者你知道要删除哪一行。



如果单一实体是指一张表，那么答案仍然是否 - 该表仍然存在，但将为空（请参阅上面的文档链接）。

在该实例中，您将需要使用 DROP TABLE [ ^ ]。例如。

  IF   OBJECT_ID （N  '  dbo.tablename'，N '  U'） IS   NOT   NULL  
  DROP   TABLE  dbo.tablename; 

或

  IF   EXISTS （ SELECT  *  FROM  sys.objects  WHERE  object_id =  OBJECT_ID （N '  [dbo]。[tablename]'） AND   TYPE   IN （N     U'））
  DROP   TABLE  [dbo]。[tablename] 

谢谢。 ................

if there any possible to delete single entity using TRUNCATE in sql

解决方案

If by "single entity" you mean a single row then the answer is "No" - you cannot use Truncate in sql to do that - see the Documentation[^] for Truncate

Quote:

Removes all rows from a table without logging the individual row deletions. TRUNCATE TABLE is similar to the DELETE statement with no WHERE clause; however, TRUNCATE TABLE is faster and uses fewer system and transaction log resources.

If you have the means of identifying which row you want to remove then include those details in a WHERE clause e.g.

DELETE FROM tablename WHERE ID=7

or

DELETE FROM tablename where column1 = 'A' and column2 = '2'

or however you know which row to delete.

If by "single entity" you mean a table then the answer is still "No" - the table will still exist but will be empty (refer to documentation link above).
In that instance you will need to use DROP TABLE[^]. E.g.

IF OBJECT_ID(N'dbo.tablename', N'U') IS NOT NULL
    DROP TABLE dbo.tablename;

or

IF EXISTS (SELECT * FROM sys.objects WHERE object_id = OBJECT_ID(N'[dbo].[tablename]') AND TYPE IN (N'U'))
DROP TABLE [dbo].[tablename]

thank you. ................

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