如何从SQL Server表对象生成类?

我说的不是使用ORM。我只需要创建实体(简单类)。喜欢的东西:

    public class Person 
    {
        public string Name { get;set; }
        public string Phone { get;set; }
    }

给定一个表,比如:

+----+-------+----------------+
| ID | Name  |     Phone      |
+----+-------+----------------+
|  1 | Alice | (555) 555-5550 |
|  2 | Bob   | (555) 555-5551 |
|  3 | Cathy | (555) 555-5552 |
+----+-------+----------------+



当前回答

要打印带有注释(摘要)的NULLABLE属性,使用这个。 这是对第一个答案的轻微修改

declare @TableName sysname = 'TableName'
declare @result varchar(max) = 'public class ' + @TableName + '
{'
select @result = @result 
+ CASE WHEN ColumnDesc IS NOT NULL THEN '
    /// <summary>
    /// ' + ColumnDesc + '
    /// </summary>' ELSE '' END
+ '
    public ' + ColumnType + ' ' + ColumnName + ' { get; set; }'
from
(
    select 
        replace(col.name, ' ', '_') ColumnName,
        column_id,
        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 + CASE WHEN col.is_nullable=1 AND typ.name NOT IN ('binary', 'varbinary', 'image', 'text', 'ntext', 'varchar', 'nvarchar', 'char', 'nchar') THEN '?' ELSE '' END ColumnType,
        colDesc.colDesc AS ColumnDesc
    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
    OUTER APPLY (
    SELECT TOP 1 CAST(value AS NVARCHAR(max)) AS colDesc
    FROM
       sys.extended_properties
    WHERE
       major_id = col.object_id
       AND
       minor_id = COLUMNPROPERTY(major_id, col.name, 'ColumnId')
    ) colDesc            
    where object_id = object_id(@TableName)
) t
order by column_id

set @result = @result  + '
}'

print @result

其他回答

Visual Studio杂志发表了这篇文章:

为SQL查询结果生成。net POCO类

它有一个可下载的项目,你可以构建,给它你的SQL信息,它会为你制作出类。

现在,如果该工具刚刚为SELECT、INSERT和UPDATE创建了SQL命令....

之前的解决方案的一个小补充: object_id(@TableName)仅在默认模式中有效。

(Select id from sysobjects where name = @TableName)

只要@tableName是唯一的,就可以在任何模式中工作。

为了感谢Alex的解决方案和Guilherme的要求,我为MySQL生成c#类做了这个

set @schema := 'schema_name';
set @table := 'table_name';
SET group_concat_max_len = 2048;
SELECT 
    concat('public class ', @table, '\n{\n', GROUP_CONCAT(a.property_ SEPARATOR '\n'), '\n}') class_
FROM 
    (select
        CONCAT(
        '\tpublic ',
        case 
            when DATA_TYPE = 'bigint' then 'long'
            when DATA_TYPE = 'BINARY' then 'byte[]'
            when DATA_TYPE = 'bit' then 'bool'
            when DATA_TYPE = 'char' then 'string'
            when DATA_TYPE = 'date' then 'DateTime'
            when DATA_TYPE = 'datetime' then 'DateTime'
            when DATA_TYPE = 'datetime2' then 'DateTime'
            when DATA_TYPE = 'datetimeoffset' then 'DateTimeOffset'
            when DATA_TYPE = 'decimal' then 'decimal'
            when DATA_TYPE = 'double' then 'double'
            when DATA_TYPE = 'float' then 'float'
            when DATA_TYPE = 'image' then 'byte[]'
            when DATA_TYPE = 'int' then 'int'
            when DATA_TYPE = 'money' then 'decimal'
            when DATA_TYPE = 'nchar' then 'char'
            when DATA_TYPE = 'ntext' then 'string'
            when DATA_TYPE = 'numeric' then 'decimal'
            when DATA_TYPE = 'nvarchar' then 'string'
            when DATA_TYPE = 'real' then 'double'
            when DATA_TYPE = 'smalldatetime' then 'DateTime'
            when DATA_TYPE = 'smallint' then 'short'
            when DATA_TYPE = 'smallmoney' then 'decimal'
            when DATA_TYPE = 'text' then 'string'
            when DATA_TYPE = 'time' then 'TimeSpan'
            when DATA_TYPE = 'timestamp' then 'DateTime'
            when DATA_TYPE = 'tinyint' then 'byte'
            when DATA_TYPE = 'uniqueidentifier' then 'Guid'
            when DATA_TYPE = 'varbinary' then 'byte[]'
            when DATA_TYPE = 'varchar' then 'string'
            else '_UNKNOWN_'
        end, ' ', 
        COLUMN_NAME, ' {get; set;}') as property_
    FROM INFORMATION_SCHEMA.COLUMNS
    WHERE table_name = @table AND table_schema = @schema) a
;

谢谢Alex和Guilherme!

抓取QueryFirst, visual studio扩展,从SQL查询生成包装类。你不仅得到…

public class MyClass{
    public string MyProp{get;set;}
    public int MyNumberProp{get;set;}
    ...
}

作为奖励,它还会……

public class MyQuery{
    public static IEnumerable<MyClass>Execute(){}
    public static MyClass GetOne(){}
    ...
}

您确定要将类直接基于表吗?表是属于DB的静态规范化数据存储概念。类是动态的、流动的、一次性的、特定于上下文的,也许是非规范化的。为什么不为您想要的操作数据编写真正的查询,然后让QueryFirst从中生成类呢?

如果你可以访问SQL Server 2016,你可以使用FOR JSON(包含INCLUDE_NULL_VALUES)选项从选择语句中获取JSON输出。复制输出,然后在Visual Studio中,粘贴special ->,粘贴JSON作为类。

算是预算上的解决方案,但可能会节省一些时间。