SQL中print、sp_helptext的限制与扩展

IF OBJECT_ID(N'sp_print_all') IS NOT NULL
BEGIN
DROP PROCEDURE sp_print_all
END
GO
CREATE PROCEDURE sp_print_all (@dynamic_sql NVARCHAR(MAX))
AS
DECLARE @start INT
DECLARE @len INT
SET @start = 1
SET @len = 4000
WHILE (@start < LEN(@dynamic_sql))
BEGIN
PRINT SUBSTRING(@dynamic_sql, @start, @len)
SET @start = @start + @len
END
PRINT SUBSTRING(@dynamic_sql, @start, @len)
GO 

IF OBJECT_ID(N'sp_helptext_user') IS NOT NULL
BEGIN
DROP PROCEDURE sp_helptext_user
END
GO
CREATE PROCEDURE sp_helptext_user(@obj_name NVARCHAR(200) = '')
AS
SET NOCOUNT ON;
DECLARE @text NVARCHAR(MAX)
,@i INT
,@text2 NVARCHAR(MAX)
,@db_name SYSNAME
,@obj_id BIGINT
SET @db_name = PARSENAME(@obj_name ,3)
IF @db_name IS NULL
SET @db_name = DB_NAME()
ELSE 
IF @db_name <> DB_NAME()
BEGIN
RAISERROR(15250 ,-1 ,-1)
RETURN (1)
END
SET @obj_id = OBJECT_ID(@obj_name)
IF @obj_id IS NULL
BEGIN
RAISERROR(15009 ,-1 ,-1 ,@obj_name ,@db_name)
RETURN (1)
END
SELECT @text = [definition]
FROM sys.all_sql_modules
WHERE [object_id] = @obj_id
WHILE LEN(@text) > 2000
BEGIN
SET @i = CHARINDEX(CHAR(13) ,@text ,2000) 
SET @text2 = LEFT(@text ,@i)
SET @text = SUBSTRING(@text ,@i + 2 ,LEN(@text)) 
PRINT @text2
END
PRINT @text
SET NOCOUNT OFF;
GO 

USE pubs
EXEC sp_helptext 'employee_insupd'