如何检查SQL Server约束是否存在？

SELECt
*
FROM INFORMATION_SCHEMA.REFERENTIAL_ConSTRAINTS

否则尝试一下

  SELECt OBJECT_NAME(OBJECT_ID) AS NameofConstraint,SCHEMA_NAME(schema_id) AS SchemaName,OBJECT_NAME(parent_object_id) AS TableName,type_desc AS ConstraintTypeFROM sys.objectsWHERe type_desc LIKE '%CONSTRAINT'

或者

IF EXISTS(SELECt 1 FROM sys.foreign_keys WHERe parent_object_id = OBJECT_ID(N'dbo.TableName')) BEGIN ALTER TABLE TableName DROP ConSTRAINT ConSTRAINTNAME END