ms sql,disable and enable all constraints,delete data in all tables -script-

-- disable all constraints
EXEC sp_msforeachtable "ALTER TABLE ? NOCHECK CONSTRAINT all"

-- delete data in all tables
EXEC sp_MSForEachTable "DELETE FROM ?"

-- enable all constraints
exec sp_msforeachtable "ALTER TABLE ? WITH CHECK CHECK CONSTRAINT all"

EXEC sp_MSforeachtable "DBCC CHECKIDENT ( '?', RESEED, 0)"