我们走在JAVA的光明大道上 — Wed, 02 May 2007 20:16:00 GMT

CREATE TABLE img (id_num int IDENTITY(1,1), company_name sysname)
INSERT img(company_name) VALUES ('New Moon Books')
INSERT img(company_name) VALUES ('Lucerne Publishing')
-- SET IDENTITY_INSERT ON and use in img table.
SET IDENTITY_INSERT img ON

DECLARE @minidentval smallint
DECLARE @nextidentval smallint
SELECT @minidentval = MIN(IDENTITYCOL) FROM img
IF @minidentval = IDENT_SEED('img')
    SELECT @nextidentval = MIN(IDENTITYCOL) + IDENT_INCR('img')
    FROM img t1
    WHERE IDENTITYCOL BETWEEN IDENT_SEED('img') AND 32766 AND
      NOT    EXISTS (SELECT * FROM img t2
          WHERE t2.IDENTITYCOL = t1.IDENTITYCOL + IDENT_INCR('img'))
ELSE
    SELECT @nextidentval = IDENT_SEED('img')
SET IDENTITY_INSERT img OFF

IDENTITYCOL:�q�回表中identity�?
IDENT_SEED(表名):IDENT_SEED() 函数�q�回表中标识性字�D�identity column 的初�?
IDENT_INCR(表名):�q�回identity列的增量�?
SET IDENTITY_INSERT�Q�允许将昑ּ�值插入表的标识列�?br>
�q�是不能完全理解,请哪位高人分析分�?

我们走在JAVA的光明大道上 2007-05-03 04:16 发表评论

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