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  • 存储过程示例


    A. 使用带有复杂 SELECT 语句的简单过程
    下面的存储过程从四个表的联接中返回所有作者(提供了姓名)、出版的书籍以及出版社。该存储过程不使用任何参数。

    USE pubs
    IF EXISTS (SELECT name FROM sysobjects
             WHERE name = 'au_info_all' AND type = 'P')
       DROP PROCEDURE au_info_all
    GO
    CREATE PROCEDURE au_info_all
    AS
    SELECT au_lname, au_fname, title, pub_name
       FROM authors a INNER JOIN titleauthor ta
          ON a.au_id = ta.au_id INNER JOIN titles t
          ON t.title_id = ta.title_id INNER JOIN publishers p
          ON t.pub_id = p.pub_id
    GO

    au_info_all 存储过程可以通过以下方法执行:

    EXECUTE au_info_all
    -- Or
    EXEC au_info_all

    如果该过程是批处理中的第一条语句,则可使用:

    au_info_all

    B. 使用带有参数的简单过程
    下面的存储过程从四个表的联接中只返回指定的作者(提供了姓名)、出版的书籍以及出版社。该存储过程接受与传递的参数精确匹配的值。

    USE pubs
    IF EXISTS (SELECT name FROM sysobjects
             WHERE name = 'au_info' AND type = 'P')
       DROP PROCEDURE au_info
    GO
    USE pubs
    GO
    CREATE PROCEDURE au_info
       @lastname varchar(40),
       @firstname varchar(20)
    AS
    SELECT au_lname, au_fname, title, pub_name
       FROM authors a INNER JOIN titleauthor ta
          ON a.au_id = ta.au_id INNER JOIN titles t
          ON t.title_id = ta.title_id INNER JOIN publishers p
          ON t.pub_id = p.pub_id
       WHERE  au_fname = @firstname
          AND au_lname = @lastname
    GO

    au_info 存储过程可以通过以下方法执行:

    EXECUTE au_info 'Dull', 'Ann'
    -- Or
    EXECUTE au_info @lastname = 'Dull', @firstname = 'Ann'
    -- Or
    EXECUTE au_info @firstname = 'Ann', @lastname = 'Dull'
    -- Or
    EXEC au_info 'Dull', 'Ann'
    -- Or
    EXEC au_info @lastname = 'Dull', @firstname = 'Ann'
    -- Or
    EXEC au_info @firstname = 'Ann', @lastname = 'Dull'

    如果该过程是批处理中的第一条语句,则可使用:

    au_info 'Dull', 'Ann'
    -- Or
    au_info @lastname = 'Dull', @firstname = 'Ann'
    -- Or
    au_info @firstname = 'Ann', @lastname = 'Dull'

    C. 使用带有通配符参数的简单过程
    下面的存储过程从四个表的联接中只返回指定的作者(提供了姓名)、出版的书籍以及出版社。该存储过程对传递的参数进行模式匹配,如果没有提供参数,则使用预设的默认值。

    USE pubs
    IF EXISTS (SELECT name FROM sysobjects
          WHERE name = 'au_info2' AND type = 'P')
       DROP PROCEDURE au_info2
    GO
    USE pubs
    GO
    CREATE PROCEDURE au_info2
       @lastname varchar(30) = 'D%',
       @firstname varchar(18) = '%'
    AS
    SELECT au_lname, au_fname, title, pub_name
    FROM authors a INNER JOIN titleauthor ta
       ON a.au_id = ta.au_id INNER JOIN titles t
       ON t.title_id = ta.title_id INNER JOIN publishers p
       ON t.pub_id = p.pub_id
    WHERE au_fname LIKE @firstname
       AND au_lname LIKE @lastname
    GO

    au_info2 存储过程可以用多种组合执行。下面只列出了部分组合:

    EXECUTE au_info2
    -- Or
    EXECUTE au_info2 'Wh%'
    -- Or
    EXECUTE au_info2 @firstname = 'A%'
    -- Or
    EXECUTE au_info2 '[CK]ars[OE]n'
    -- Or
    EXECUTE au_info2 'Hunter', 'Sheryl'
    -- Or
    EXECUTE au_info2 'H%', 'S%'

    D. 使用 OUTPUT 参数
    OUTPUT 参数允许外部过程、批处理或多条 Transact-SQL 语句访问在过程执行期间设置的某个值。下面的示例创建一个存储过程 (titles_sum),并使用一个可选的输入参数和一个输出参数。

    首先,创建过程:

    USE pubs
    GO
    IF EXISTS(SELECT name FROM sysobjects
          WHERE name = 'titles_sum' AND type = 'P')
       DROP PROCEDURE titles_sum
    GO
    USE pubs
    GO
    CREATE PROCEDURE titles_sum @@TITLE varchar(40) = '%', @@SUM money OUTPUT
    AS
    SELECT 'Title Name' = title
    FROM titles
    WHERE title LIKE @@TITLE
    SELECT @@SUM = SUM(price)
    FROM titles
    WHERE title LIKE @@TITLE
    GO

    接下来,将该 OUTPUT 参数用于控制流语言。


    说明  OUTPUT 变量必须在创建表和使用该变量时都进行定义。


    参数名和变量名不一定要匹配,不过数据类型和参数位置必须匹配(除非使用 @@SUM = variable 形式)。

    DECLARE @@TOTALCOST money
    EXECUTE titles_sum 'The%', @@TOTALCOST OUTPUT
    IF @@TOTALCOST < 200
    BEGIN
       PRINT ' '
       PRINT 'All of these titles can be purchased for less than $200.'
    END
    ELSE
       SELECT 'The total cost of these titles is $'
             + RTRIM(CAST(@@TOTALCOST AS varchar(20)))

    下面是结果集:

    Title Name                                                              
    ------------------------------------------------------------------------
    The Busy Executive's Database Guide
    The Gourmet Microwave
    The Psychology of Computer Cooking

    (3 row(s) affected)

    Warning, null value eliminated from aggregate.
     
    All of these titles can be purchased for less than $200.

    E. 使用 OUTPUT 游标参数
    OUTPUT 游标参数用来将存储过程的局部游标传递回调用批处理、存储过程或触发器。

    首先,创建以下过程,在 titles 表上声明并打开一个游标:

    USE pubs
    IF EXISTS (SELECT name FROM sysobjects
          WHERE name = 'titles_cursor' and type = 'P')
    DROP PROCEDURE titles_cursor
    GO
    CREATE PROCEDURE titles_cursor @titles_cursor CURSOR VARYING OUTPUT
    AS
    SET @titles_cursor = CURSOR
    FORWARD_ONLY STATIC FOR
    SELECT *
    FROM titles

    OPEN @titles_cursor
    GO

    接下来,执行一个批处理,声明一个局部游标变量,执行上述过程以将游标赋值给局部变量,然后从该游标提取行。

    USE pubs
    GO
    DECLARE @MyCursor CURSOR
    EXEC titles_cursor @titles_cursor = @MyCursor OUTPUT
    WHILE (@@FETCH_STATUS = 0)
    BEGIN
       FETCH NEXT FROM @MyCursor
    END
    CLOSE @MyCursor
    DEALLOCATE @MyCursor
    GO

    F. 使用 WITH RECOMPILE 选项
    如果为过程提供的参数不是典型的参数,并且新的执行计划不应高速缓存或存储在内存中,WITH RECOMPILE 子句会很有帮助。

    USE pubs
    IF EXISTS (SELECT name FROM sysobjects
          WHERE name = 'titles_by_author' AND type = 'P')
       DROP PROCEDURE titles_by_author
    GO
    CREATE PROCEDURE titles_by_author @@LNAME_PATTERN varchar(30) = '%'
    WITH RECOMPILE
    AS
    SELECT RTRIM(au_fname) + ' ' + RTRIM(au_lname) AS 'Authors full name',
       title AS Title
    FROM authors a INNER JOIN titleauthor ta
       ON a.au_id = ta.au_id INNER JOIN titles t
       ON ta.title_id = t.title_id
    WHERE au_lname LIKE @@LNAME_PATTERN
    GO

    G. 使用 WITH ENCRYPTION 选项
    WITH ENCRYPTION 子句对用户隐藏存储过程的文本。下例创建加密过程,使用 sp_helptext 系统存储过程获取关于加密过程的信息,然后尝试直接从 syscomments 表中获取关于该过程的信息。

    IF EXISTS (SELECT name FROM sysobjects
          WHERE name = 'encrypt_this' AND type = 'P')
       DROP PROCEDURE encrypt_this
    GO
    USE pubs
    GO
    CREATE PROCEDURE encrypt_this
    WITH ENCRYPTION
    AS
    SELECT *
    FROM authors
    GO

    EXEC sp_helptext encrypt_this

    下面是结果集:

    The object's comments have been encrypted.

    接下来,选择加密存储过程内容的标识号和文本。

    SELECT c.id, c.text
    FROM syscomments c INNER JOIN sysobjects o
       ON c.id = o.id
    WHERE o.name = 'encrypt_this'

    下面是结果集:


    说明  text 列的输出显示在单独一行中。执行时,该信息将与 id 列信息出现在同一行中。


    id         text                                                       
    ---------- ------------------------------------------------------------
    1413580074 ?????????????????????????????????e??????????????????????????????????????????????????????????????????????????

    (1 row(s) affected)

    H. 创建用户定义的系统存储过程
    下面的示例创建一个过程,显示表名以 emp 开头的所有表及其对应的索引。如果没有指定参数,该过程将返回表名以 sys 开头的所有表(及索引)。

    IF EXISTS (SELECT name FROM sysobjects
          WHERE name = 'sp_showindexes' AND type = 'P')
       DROP PROCEDURE sp_showindexes
    GO
    USE master
    GO
    CREATE PROCEDURE sp_showindexes
       @@TABLE varchar(30) = 'sys%'
    AS
    SELECT o.name AS TABLE_NAME,
       i.name AS INDEX_NAME,
       indid AS INDEX_ID
    FROM sysindexes i INNER JOIN sysobjects o
       ON o.id = i.id
    WHERE o.name LIKE @@TABLE
    GO        
    USE pubs
    EXEC sp_showindexes 'emp%'
    GO

    下面是结果集:

    TABLE_NAME       INDEX_NAME       INDEX_ID
    ---------------- ---------------- ----------------
    employee         employee_ind     1
    employee         PK_emp_id        2

    (2 row(s) affected)

    I. 使用延迟名称解析
    下面的示例显示四个过程以及延迟名称解析的各种可能使用方式。尽管引用的表或列在编译时不存在,但每个存储过程都可创建。

    IF EXISTS (SELECT name FROM sysobjects
          WHERE name = 'proc1' AND type = 'P')
       DROP PROCEDURE proc1
    GO
    -- Creating a procedure on a nonexistent table.
    USE pubs
    GO
    CREATE PROCEDURE proc1
    AS
       SELECT *
       FROM does_not_exist
    GO 
    -- Here is the statement to actually see the text of the procedure.
    SELECT o.id, c.text
    FROM sysobjects o INNER JOIN syscomments c
       ON o.id = c.id
    WHERE o.type = 'P' AND o.name = 'proc1'
    GO
    USE master
    GO
    IF EXISTS (SELECT name FROM sysobjects
          WHERE name = 'proc2' AND type = 'P')
       DROP PROCEDURE proc2
    GO
    -- Creating a procedure that attempts to retrieve information from a
    -- nonexistent column in an existing table.
    USE pubs
    GO
    CREATE PROCEDURE proc2
    AS
       DECLARE @middle_init char(1)
       SET @middle_init = NULL
       SELECT au_id, middle_initial = @middle_init
       FROM authors
    GO 
    -- Here is the statement to actually see the text of the procedure.
    SELECT o.id, c.text
    FROM sysobjects o INNER JOIN syscomments c
       ON o.id = c.id
    WHERE o.type = 'P' and o.name = 'proc2'

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  • 原文地址:https://www.cnblogs.com/eebb/p/757720.html
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