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澳门新濠3559:3、修改字段类型,在网上看了许多

时间:2019-11-07 13:43来源:数据库
修改字段类型步骤: 最近项目需要做什么数据字典,需要表结构信息。在网上看了许多关于表结构信息的查询,感觉都不怎么样。相对好一点就是《 基于SQL2005SQL2008表结构信息查询升级

修改字段类型步骤:

最近项目需要做什么数据字典,需要表结构信息。在网上看了许多关于表结构信息的查询,感觉都不怎么样。相对好一点就是《基于SQL2005 SQL2008 表结构信息查询升级版的详解(含外键信息)》 ,但是这里有一点小问题,缺少一个过滤以致运行有一点小bug。在AdventureWorks2012数据库中的Address表查询结果如图:
澳门新濠3559 1
在查询过滤中我们添加以下信息就ok了:
AND g.class_desc = 'OBJECT_OR_COLUMN'
修改后的SQL如下:

1、首先需要检查字段约束

复制代码 代码如下:

2、删除字段约束

SELECT  表名 = CASE WHEN a.colorder = 1 THEN d.name
                  ELSE ''
             END ,
        表说明 = CASE WHEN a.colorder = 1 THEN ISNULL(f.value, '')
                   ELSE ''
              END ,
        字段序号 = a.colorder ,
        字段名 = a.name ,
        标识 = CASE WHEN COLUMNPROPERTY(a.id, a.name, 'IsIdentity') = 1 THEN '√'
                  ELSE ''
             END ,
        主键 = CASE WHEN EXISTS ( SELECT  1
                                FROM    dbo.sysindexes si
                                        INNER JOIN dbo.sysindexkeys sik ON si.id = sik.id
                                                              AND si.indid = sik.indid
                                        INNER JOIN dbo.syscolumns sc ON sc.id = sik.id
                                                              AND sc.colid = sik.colid
                                        INNER JOIN dbo.sysobjects so ON so.name = so.name
                                                              AND so.xtype = 'PK'
                                WHERE   sc.id = a.id
                                        AND sc.colid = a.colid ) THEN '√'
                  ELSE ''
             END ,
        外键 = CASE WHEN tony.fkey IS NOT NULL
                       AND tony.fkey = a.colid THEN '√'
                  ELSE ''
             END ,
        外键表 = CASE WHEN tony.fkey IS NOT NULL
                        AND tony.fkey = a.colid THEN OBJECT_NAME(tony.fkeyid)
                   ELSE ''
              END ,
        外键字段 = CASE WHEN tony.fkey IS NOT NULL
                         AND tony.fkey = a.colid
                    THEN ( SELECT   name
                           FROM     syscolumns
                           WHERE    colid = tony.fkey
                                    AND id = tony.fkeyid
                         )
                    ELSE ''
               END ,
        类型 = b.name ,
        长度 = a.length ,
        精度 = COLUMNPROPERTY(a.id, a.name, 'PRECISION') ,
        小数位数 = ISNULL(COLUMNPROPERTY(a.id, a.name, 'Scale'), 0) ,
        允许空 = CASE WHEN a.isnullable = 1 THEN '√'
                   ELSE ''
              END ,
        默认值 = ISNULL(e.text, '') ,
        字段说明 = ISNULL(g.[value], '') ,
        创建时间 = d.crdate ,
        更改时间 = CASE WHEN a.colorder = 1 THEN d.refdate
                    ELSE NULL
               END
FROM    dbo.syscolumns a
        LEFT JOIN dbo.systypes b ON a.xtype = b.xusertype
        INNER JOIN dbo.sysobjects d ON a.id = d.id
                                       AND d.xtype = 'U'
                                       AND d.status >= 0
        LEFT JOIN dbo.syscomments e ON a.cdefault = e.id
        LEFT JOIN sys.extended_properties g ON a.id = g.major_id
                                               AND a.colid = g.minor_id
                                               AND g.class_desc = 'OBJECT_OR_COLUMN'
        LEFT JOIN sys.extended_properties f ON d.id = f.major_id
                                               AND f.minor_id = 0
        LEFT JOIN sysobjects htl ON htl.parent_obj = d.id
                                    AND htl.xtype = 'F'
        LEFT JOIN sysforeignkeys tony ON htl.id = tony.constid
WHERE   d.name = 'Address'  --这里输入包含表名称的条件
ORDER BY d.id ,
        a.colorder

3、修改字段类型

运行结果如图:
澳门新濠3559 2
我不怎么喜欢它的“类型”信息,一般的varchar都会有长度信息,还有这个查询对于SQL 2012的新数据类型不支持,该SQL里面的嵌套查询比较多,于是我就自己重新写了一个SQL。
这里提醒大家尽量用INFORMATION_SCHEMA.XXX视图而不去用sys.XXX视图。
新的SQL如下:

4、加上字段约束

复制代码 代码如下:

--不加这个条件,库中所有默认约束都可以看到

SELECT
 --OBJECT_ID(a.TABLE_SCHEMA + '.' + a.TABLE_NAME) AS [object_id] ,
        CASE WHEN a.ORDINAL_POSITION = 1
             THEN a.TABLE_SCHEMA + '.' + a.TABLE_NAME
             ELSE ''
        END AS TABLE_NAME ,
        CASE WHEN ( a.ORDINAL_POSITION = 1
                    AND p1.value IS NOT NULL
                  ) THEN p1.value
             ELSE ''
        END AS TABLE_Description ,
        a.COLUMN_NAME ,
        CASE WHEN ( ( CHARINDEX('char', a.DATA_TYPE) > 0
                      OR CHARINDEX('binary', a.DATA_TYPE) > 0
                    )
                    AND a.CHARACTER_MAXIMUM_LENGTH <> -1
                  )
             THEN a.DATA_TYPE + '('
                  + CAST(a.CHARACTER_MAXIMUM_LENGTH AS VARCHAR(4)) + ')'
             WHEN ( ( CHARINDEX('CHAR', a.DATA_TYPE) > 0
                      OR CHARINDEX('binary', a.DATA_TYPE) > 0
                    )
                    AND a.CHARACTER_MAXIMUM_LENGTH = -1
                  ) THEN a.DATA_TYPE + '(max)'
             WHEN ( CHARINDEX('numeric', a.DATA_TYPE) > 0 )
             THEN a.DATA_TYPE + '(' + CAST(a.NUMERIC_PRECISION AS VARCHAR(4))
                  + ',' + CAST(a.NUMERIC_SCALE AS VARCHAR(4)) + ')'
             ELSE a.DATA_TYPE
        END AS COLUMN_TYPE ,
        CASE WHEN c.IS_IDENTITY = 1 THEN 'YES'
             ELSE 'NO'
        END AS IS_澳门新濠3559,IDENTITY ,
        a.IS_NULLABLE ,
        CASE WHEN a.COLUMN_DEFAULT IS NULL THEN ''
             ELSE a.COLUMN_DEFAULT
        END AS Default_Value ,
        CASE WHEN p.value IS NULL THEN ''
             ELSE p.value
        END AS [COLUMN_Description] ,
        CASE WHEN o.name IS  NULL THEN ''
             ELSE '√'
        END AS Is_PrimaryKey ,
        CASE WHEN f.parent_column_id IS NULL THEN ''
             ELSE '√'
        END AS Is_Foreignkeys ,
        CASE WHEN referenced_object_id IS NULL THEN ''
             ELSE OBJECT_NAME(referenced_object_id)
        END AS Foreign_Table ,
        CASE WHEN referenced_object_id IS NULL THEN ''
             ELSE ( SELECT  name
                    FROM    sys.columns
                    WHERE   object_id = f.referenced_object_id
                            AND column_id = f.referenced_column_id
                  )
        END AS Foreign_key
FROM    INFORMATION_SCHEMA.COLUMNS a
        INNER JOIN sys.columns c ON OBJECT_ID(a.TABLE_SCHEMA + '.'
                                              + a.TABLE_NAME) = c.OBJECT_ID
                                    AND a.COLUMN_NAME = c.NAME
        LEFT JOIN INFORMATION_SCHEMA.KEY_COLUMN_USAGE b ON a.TABLE_SCHEMA = b.TABLE_SCHEMA
                                                           AND a.TABLE_NAME = b.TABLE_NAME
                                                           AND a.COLUMN_NAME = b.COLUMN_NAME
        LEFT JOIN sys.sysobjects o ON o.name = b.CONSTRAINT_NAME
                                      AND o.xtype = 'PK'
        LEFT JOIN sys.extended_properties p ON OBJECT_ID(a.TABLE_SCHEMA + '.'
                                                         + a.TABLE_NAME) = p.major_id
                                               AND a.Ordinal_position = p.minor_id
                                               AND p.class_desc = 'OBJECT_OR_COLUMN'
        LEFT JOIN sys.extended_properties p1 ON OBJECT_ID(a.TABLE_SCHEMA + '.'
                                                          + a.TABLE_NAME) = p1.major_id
                                                AND p1.minor_id = 0
        LEFT JOIN SYS.foreign_key_columns f ON OBJECT_ID(a.TABLE_SCHEMA + '.'
                                                         + a.TABLE_NAME) = f.parent_object_id
                                               AND a.ORDINAL_POSITION = f.parent_column_id
WHERE   a.TABLE_NAME = 'Address'
-- a.TABLE_NAME IN (SELECT name FROM sys.tables)
ORDER BY a.TABLE_SCHEMA,a.TABLE_NAME, a.ORDINAL_POSITION

SELECT  a.name AS DFName ,

运行效果如图:
澳门新濠3559 3
有不对的地方还请大家拍砖!谢谢!

        b.Name AS ColumnName

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FROM    sys.objects a

        INNER JOIN sys.columns b ON a.object_id = b.default_object_id

WHERE   a.type = 'D'

        AND b.object_id = OBJECT_ID('表名')

        AND b.name='字段名'

 

----1.删除默认约束

--ALTER TABLE 表名DROP CONSTRAINT 约束名

----2.修改字段类型

--ALTER TABLE 表名

--ALTER COLUMN 字段名 BIGINT NOT NULL

----3.加上默认约束

--ALTER TABLE 表名ADD  CONSTRAINT 约束名  DEFAULT ((0)) FOR 字段名

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