从数据库表生成类

内容来源于 Stack Overflow,并遵循CC BY-SA 3.0许可协议进行翻译与使用

  • 回答 (2)
  • 关注 (0)
  • 查看 (30)

如何从SQLServer的表中生成类?

我不是说用ORM。我只需要创建实体(简单类)。类似于:

public class Person 
{
    public string Name { get;set; }
    public string Phone { get;set; }
}
提问于
用户回答回答于

将@TableName设置为表的名称。

declare @TableName sysname = 'TableName'
declare @Result varchar(max) = 'public class ' + @TableName + '
{'

select @Result = @Result + '
    public ' + ColumnType + NullableSign + ' ' + ColumnName + ' { get; set; }
'
from
(
    select 
        replace(col.name, ' ', '_') ColumnName,
        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 '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
        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
用户回答回答于

下面是SQL:

DECLARE @TableName VARCHAR(MAX) = 'NewsItem' -- Replace 'NewsItem' with your table name
DECLARE @TableSchema VARCHAR(MAX) = 'Markets' -- Replace 'Markets' with your schema name
DECLARE @result varchar(max) = ''

SET @result = @result + 'using System;' + CHAR(13) + CHAR(13) 

IF (@TableSchema IS NOT NULL) 
BEGIN
    SET @result = @result + 'namespace ' + @TableSchema  + CHAR(13) + '{' + CHAR(13) 
END

SET @result = @result + 'public class ' + @TableName + CHAR(13) + '{' + CHAR(13) 

SET @result = @result + '#region Instance Properties' + CHAR(13)  

SELECT @result = @result + CHAR(13) 
    + ' public ' + ColumnType + ' ' + ColumnName + ' { get; set; } ' + CHAR(13) 
FROM
(
    SELECT  c.COLUMN_NAME   AS ColumnName 
        , CASE c.DATA_TYPE   
            WHEN 'bigint' THEN
                CASE C.IS_NULLABLE
                    WHEN 'YES' THEN 'Int64?' ELSE 'Int64' END
            WHEN 'binary' THEN 'Byte[]'
            WHEN 'bit' THEN 
                CASE C.IS_NULLABLE
                    WHEN 'YES' THEN 'Boolean?' ELSE 'Boolean' END            
            WHEN 'char' THEN 'String'
            WHEN 'date' THEN
                CASE C.IS_NULLABLE
                    WHEN 'YES' THEN 'DateTime?' ELSE 'DateTime' END                        
            WHEN 'datetime' THEN
                CASE C.IS_NULLABLE
                    WHEN 'YES' THEN 'DateTime?' ELSE 'DateTime' END                        
            WHEN 'datetime2' THEN  
                CASE C.IS_NULLABLE
                    WHEN 'YES' THEN 'DateTime?' ELSE 'DateTime' END                        
            WHEN 'datetimeoffset' THEN 
                CASE C.IS_NULLABLE
                    WHEN 'YES' THEN 'DateTimeOffset?' ELSE 'DateTimeOffset' END                                    
            WHEN 'decimal' THEN  
                CASE C.IS_NULLABLE
                    WHEN 'YES' THEN 'Decimal?' ELSE 'Decimal' END                                    
            WHEN 'float' THEN 
                CASE C.IS_NULLABLE
                    WHEN 'YES' THEN 'Single?' ELSE 'Single' END                                    
            WHEN 'image' THEN 'Byte[]'
            WHEN 'int' THEN  
                CASE C.IS_NULLABLE
                    WHEN 'YES' THEN 'Int32?' ELSE 'Int32' END
            WHEN 'money' THEN
                CASE C.IS_NULLABLE
                    WHEN 'YES' THEN 'Decimal?' ELSE 'Decimal' END                                                
            WHEN 'nchar' THEN 'String'
            WHEN 'ntext' THEN 'String'
            WHEN 'numeric' THEN
                CASE C.IS_NULLABLE
                    WHEN 'YES' THEN 'Decimal?' ELSE 'Decimal' END                                                            
            WHEN 'nvarchar' THEN 'String'
            WHEN 'real' THEN 
                CASE C.IS_NULLABLE
                    WHEN 'YES' THEN 'Double?' ELSE 'Double' END                                                                        
            WHEN 'smalldatetime' THEN 
                CASE C.IS_NULLABLE
                    WHEN 'YES' THEN 'DateTime?' ELSE 'DateTime' END                                    
            WHEN 'smallint' THEN 
                CASE C.IS_NULLABLE
                    WHEN 'YES' THEN 'Int16?' ELSE 'Int16'END            
            WHEN 'smallmoney' THEN  
                CASE C.IS_NULLABLE
                    WHEN 'YES' THEN 'Decimal?' ELSE 'Decimal' END                                                                        
            WHEN 'text' THEN 'String'
            WHEN 'time' THEN 
                CASE C.IS_NULLABLE
                    WHEN 'YES' THEN 'TimeSpan?' ELSE 'TimeSpan' END                                                                                    
            WHEN 'timestamp' THEN 
                CASE C.IS_NULLABLE
                    WHEN 'YES' THEN 'DateTime?' ELSE 'DateTime' END                                    
            WHEN 'tinyint' THEN 
                CASE C.IS_NULLABLE
                    WHEN 'YES' THEN 'Byte?' ELSE 'Byte' END                                                
            WHEN 'uniqueidentifier' THEN 'Guid'
            WHEN 'varbinary' THEN 'Byte[]'
            WHEN 'varchar' THEN 'String'
            ELSE 'Object'
        END AS ColumnType
        , c.ORDINAL_POSITION 
FROM    INFORMATION_SCHEMA.COLUMNS c
WHERE   c.TABLE_NAME = @TableName and ISNULL(@TableSchema, c.TABLE_SCHEMA) = c.TABLE_SCHEMA  
) t
ORDER BY t.ORDINAL_POSITION

SET @result = @result + CHAR(13) + '#endregion Instance Properties' + CHAR(13)  

SET @result = @result  + '}' + CHAR(13)

IF (@TableSchema IS NOT NULL) 
BEGIN
    SET @result = @result + CHAR(13) + '}' 
END

PRINT @result

它生成C#,如下所示:

using System;

namespace Markets
{
    public class NewsItem        {
        #region Instance Properties

        public Int32 NewsItemID { get; set; }

        public Int32? TextID { get; set; }

        public String Description { get; set; }

        #endregion Instance Properties
    }

}

然而,有时这样的代码也会派上用场。这可能只是你的技术架构师不想让你使用EF之类的东西。所以,你必须恢复到这样的代码。顺便说一句,用DataAnnoations等属性装饰每个属性也可能是一个想法。

扫码关注云+社区