Question

我想从数据库中已经存在的所有表中创建视图，这是逐个捕获表的艰巨任务，并使得创建视图XXXX作为select * from Table_name。我发现可以使用游标并且代码是：

DECLARE @TableName sysname
DECLARE @ColumnCount INT
DECLARE @ColumnID INT
DECLARE @SelectColumn NVARCHAR(500)
DECLARE @sql NVARCHAR(max) = ''

DECLARE QUERYINFO CURSOR FOR
    SELECT
        t.name AS TableName,
        ccount.ColumnCount,
        c.column_id AS ColumnID,
        CASE WHEN c.column_id <> ccount.ColumnCount
                THEN c.name + ', '
             ELSE c.name
             END AS SelectColumn
    FROM sys.tables t
    INNER JOIN sys.columns c ON t.object_id=c.object_id
    INNER JOIN (
        SELECT object_id,COUNT(*) AS ColumnCount
        FROM sys.columns
        GROUP BY object_id
    ) ccount ON t.object_id = ccount.object_id
    ORDER BY t.Name,c.column_id

OPEN QUERYINFO
FETCH NEXT FROM QUERYINFO INTO @TableName,@ColumnCount,@ColumnID,@SelectColumn
WHILE @@FETCH_STATUS = 0
BEGIN
    IF @ColumnID = 1
    BEGIN
        SET @sql = 'CREATE VIEW v_' + @TableName + ' AS SELECT ' + @SelectColumn
    END
    ELSE
    BEGIN
        SET @sql = @sql + @SelectColumn
    END 

    IF @ColumnID = @ColumnCount
    BEGIN
        SET @sql = @sql + ' FROM ' + @TableName
        EXEC sys.sp_executesql @sql
        SET @sql = ''
    END

    FETCH NEXT FROM QUERYINFO INTO @TableName,@ColumnCount,@ColumnID,@SelectColumn
END

CLOSE QUERYINFO
DEALLOCATE QUERYINFO

但它有错误，我不知道如何解决它

Answer 1

这是我对动态SQL的处理方式;首先检查视图是否存在，然后使用所有列创建它（而不是使用SELECT * FROM...）。

DECLARE @SQL nvarchar(MAX)
SET @SQL = N''


SELECT
    @SQL = @SQL + 
    N'IF EXISTS(SELECT 1 FROM sys.objects WHERE name = N''v_' + t.name + N''' AND type = N''V'') BEGIN DROP VIEW [v_' + t.name + '] END CREATE VIEW [v_' + t.name + N'] AS SELECT ' + 
        STUFF(
            (SELECT N',' + c.name
               FROM
                  sys.columns AS c
               WHERE 
                 c.OBJECT_ID = t.OBJECT_ID
               ORDER BY
                 column_id
               FOR XML PATH(''), TYPE).value('.',N'nvarchar(max)')
        ,1,1,N'')
        + N' FROM [' + t.name + N'];'
FROM
    sys.tables AS t

EXEC sp_executesql @SQL

如何为数据库中的所有表创建视图？

1 个答案: