通过 SQL 语句生成实体类

DECLARE @TableName sysname = '表名或视图名';
DECLARE @Result VARCHAR(MAX) = 'public class ' + @TableName + '
{';
SELECT @Result = @Result + '
    /// <summary>
    /// '        + CAST(t.Summary AS VARCHAR(MAX)) + '
    /// </summary>
    public '     + ColumnType + NullableSign + ' ' + ColumnName + ' { get; set; }
'
FROM
(
    SELECT REPLACE(col.name, ' ', '_') ColumnName,
           col.column_id ColumnId,
           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
                   'char'
               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,
           ISNULL(ep.value, col.name) AS Summary
    FROM sys.columns col
        JOIN sys.types typ
            ON col.system_type_id = typ.system_type_id
               AND col.user_type_id = typ.user_type_id
        LEFT JOIN sys.extended_properties ep
            ON ep.major_id = col.object_id
               AND ep.minor_id = col.column_id
    WHERE col.object_id = OBJECT_ID(@TableName)
) t
ORDER BY ColumnId;
SET @Result = @Result + '
}';
PRINT @Result;