SQLServer之数据库表转化为实体类【带注释】

1.在开发过程中，有时候需要将数据库表转化为实体类。手敲除了不方便，还容易出错。本着DRY+懒人原则,参考了一位老司机的博客【见底部】，并在其基础上进行了优化。【原先是不带注释的】

DECLARE @TableName sysname = 'TableName';
DECLARE @Result VARCHAR(MAX) = 'public class ' + @TableName + '
{';

SELECT  @Result = @Result  + CHAR(13) + '    ///<summary>' + CHAR(13)
        + '    ///' + CAST(desr AS NVARCHAR) + CHAR(13)
        + '    ///</summary>' + '
    public ' + ColumnType + NullableSign + ' ' + colname + ' '  + ' { get; set; }
    '
FROM    (SELECT    column_id ColumnId,
                    ISNULL(t.desctr, '') AS desr,
                    col.name colname,
                     CASE typ.name
                      WHEN 'bigint' THEN 'long'
                      WHEN 'binary' THEN 'byte[]'
                      WHEN 'bit' THEN 'bool'
                      WHEN 'char' THEN 'string'
                      WHEN 'date' THEN 'DateTime'
                      WHEN 'datetime' THEN 'DateTime'
                      WHEN 'datetime2' THEN 'DateTime'
                      WHEN 'datetimeoffset' THEN 'DateTimeOffset'
                      WHEN 'decimal' THEN 'decimal'
                      WHEN 'float' THEN 'float'
                      WHEN 'image' THEN 'byte[]'
                      WHEN 'int' THEN 'int'
                      WHEN 'money' THEN 'decimal'
                      WHEN 'nchar' THEN 'string'
                      WHEN 'ntext' THEN 'string'
                      WHEN 'numeric' THEN 'decimal'
                      WHEN 'nvarchar' THEN 'string'
                      WHEN 'real' THEN 'double'
                      WHEN 'smalldatetime' THEN 'DateTime'
                      WHEN 'smallint' THEN 'short'
                      WHEN 'smallmoney' THEN 'decimal'
                      WHEN 'text' THEN 'string'
                      WHEN 'time' THEN 'TimeSpan'
                      WHEN 'timestamp' THEN 'DateTime'
                      WHEN 'tinyint' THEN 'byte'
                      WHEN 'uniqueidentifier' THEN 'Guid'
                      WHEN 'varbinary' THEN 'byte[]'
                      WHEN 'varchar' THEN 'string'
                      ELSE 'UNKNOWN_' + typ.name
                    END ColumnType ,
                    CASE WHEN col.is_nullable = 1
                              AND typ.name IN ( 'bigint', 'bit', 'date',
                                                'datetime', 'datetime2',
                                                'datetimeoffset', 'decimal',
                                                'float', 'int', 'money',
                                                'numeric', 'real',
                                                'smalldatetime', 'smallint',
                                                'smallmoney', 'time',
                                                'tinyint', 'uniqueidentifier' )
                         THEN '?'
                         ELSE ''
                    END NullableSign
          FROM      sys.columns col
                   LEFT  JOIN ( SELECT  ISNULL(CAST(g.value AS VARCHAR), '') desctr ,
                                        g.minor_id AS minor_id
                                FROM    sys.extended_properties g
                                WHERE   g.major_id = OBJECT_ID(@TableName)
                              ) t ON t.minor_id = col.column_id
                    JOIN sys.types typ ON col.system_type_id = typ.system_type_id
                                          AND col.user_type_id = typ.user_type_id   
          WHERE     object_id = OBJECT_ID(@TableName)
        ) t
ORDER BY ColumnId;

SET @Result = @Result + '
}';

PRINT @Result;