一个容易忽视的存储过程问题_数据库技巧

sql server 2005中新增加的try catch，可以很容易捕捉异常了，今天大概学习看了下，归纳下要点如下

基本用法BEGIN TRY

{ sql_statement |

statement_block }

END TRY

BEGIN CATCH

{ sql_statement |

statement_block }

END CATCH

，和普通语言的异常处理用法差不多，但要注意的是，SQL SERVER只捕捉那些不是严重的异常，当比如数据库不能连接等这类异常时，是不能捕捉的一个例子：BEGIN TRY

DECLARE @X INT

-- Divide by zero to generate Error

SET @X = 1/0

PRINT 'Command after error in TRY block'

END TRY

BEGIN CATCH

PRINT 'Error Detected'

END CATCH

PRINT 'Command after TRY/CATCH blocks'

另外try catch可以嵌套Begin TRY

delete from GrandParent where Name = 'John Smith'

print 'GrandParent deleted successfully'

End Try

Begin Catch

Print 'Error Deleting GrandParent Record'

Begin Try

delete from Parent where GrandParentID =

(select distinct ID from GrandParent where Name = 'John Smith')

Print 'Parent Deleted Successfully'

End Try

Begin Catch

print 'Error Deleting Parent'

Begin Try

delete from child where ParentId =

(select distinct ID from Parent where GrandParentID =

(select distinct ID from GrandParent where Name = 'John Smith'))

print 'Child Deleted Successfully'

End Try

Begin Catch

Print 'Error Deleting Child'

End Catch

End Catch

End Catch

另外，SQL SERVER 2005在异常机制中，提供了error类的方法方便调试，现摘抄如下，比较简单，不予以解释ERROR_NUMBER(): Returns a number associated with the error.ERROR_SEVERITY(): Returns the severity of the error.ERROR_STATE(): Returns the error state number associated with the error.ERROR_PROCEDURE(): Returns the name of the stored procedure or trigger in which the error occurred.ERROR_LINE(): Returns the line number inside the failing routine that caused the error. ERROR_MESSAGE(): Returns the complete text of the error message. The text includes the values supplied for any substitutable parameters, such as lengths, object names, or times. 最后举例子如下，使用了error类的方法BEGIN TRY