Check/Disable/Enable FK

SELECT
 (CASE WHEN OBJECTPROPERTY(CONSTID, 'CNSTISDISABLED') = 0 THEN 'ENABLED' ELSE 'DISABLED' END) AS STATUS
 ,OBJECT_NAME(CONSTID) AS CONSTRAINT_NAME
 ,OBJECT_NAME(FKEYID) AS TABLE_NAME
 ,COL_NAME(FKEYID, FKEY) AS COLUMN_NAME
 ,OBJECT_NAME(RKEYID) AS REFERENCED_TABLE_NAME
 ,COL_NAME(RKEYID, RKEY) AS REFERENCED_COLUMN_NAME
 FROM SYSFOREIGNKEYS
 ORDER BY TABLE_NAME
    , CONSTRAINT_NAME
    , REFERENCED_TABLE_NAME
    , KEYNO


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For SQL 2005 and above:
-- This SQL generates a set of SQL statements to disable every foreign
-- key in the database
select distinct
    sql = 'ALTER TABLE [' + onSchema.name + '].[' + onTable.name +
            '] NOCHECK CONSTRAINT [' + foreignKey.name + ']'
from sysforeignkeys fk inner join sysobjects foreignKey 
        on foreignKey.id = fk.constid
  inner join sys.objects onTable
        on fk.fkeyid = onTable.object_id
  inner join sys.schemas onSchema
        on onSchema.schema_id = onTable.schema_id
  inner join sysobjects againstTable 
        on fk.rkeyid = againstTable.id
where againstTable.TYPE = 'U'
  and onTable.TYPE = 'U'
  and ObjectProperty(fk.constid,'CnstIsDisabled') = 0
order by 1
-- This SQL generates a set of SQL statements to re-enable every foreign
-- key in the database
select distinct
    sql = 'ALTER TABLE [' + onSchema.name + '].[' + onTable.name +
            '] CHECK CONSTRAINT [' + foreignKey.name + ']'
from sysforeignkeys fk inner join sysobjects foreignKey 
        on foreignKey.id = fk.constid
  inner join sys.objects onTable
        on fk.fkeyid = onTable.object_id
  inner join sys.schemas onSchema
        on onSchema.schema_id = onTable.schema_id
  inner join sysobjects againstTable 
        on fk.rkeyid = againstTable.id
where againstTable.TYPE = 'U'
  and onTable.TYPE = 'U'
  and ObjectProperty(fk.constid,'CnstIsDisabled') = 1
order by 1