Generate class from database table

Solution 1:

Set @TableName to the name of your table.

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 'double'
            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 'float'
            when 'smalldatetime' then 'DateTime'
            when 'smallint' then 'short'
            when 'smallmoney' then 'decimal'
            when 'text' then 'string'
            when 'time' then 'TimeSpan'
            when 'timestamp' then 'long'
            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

Solution 2:

I could not get Alex's answer to work on Sql Server 2008 R2. So, I rewrote it using the same basic principles. It now allows for schemas and several fixes have been made for column-property mappings (including mapping nullable date types to nullable C# value types). Here is the 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 'bool?'
            ELSE 'bool'
          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 'int?'
            ELSE 'int'
          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 'Byte[]'
        WHEN 'tinyint' THEN CASE C.IS_NULLABLE
            WHEN 'YES' THEN 'Byte?'
            ELSE 'Byte'
          END
        WHEN 'uniqueidentifier' THEN CASE C.IS_NULLABLE
            WHEN 'YES' THEN 'Guid?'
            ELSE 'Guid'
          END
        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

It produces C# like the following:

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
    }

}

It may be an idea to use EF, Linq to Sql, or even Scaffolding; however, there are times when a piece of coding like this comes in handy. Frankly, I do not like using EF navigation properties where the code it generates made 19,200 separate database calls to populate a 1000 row grid. This could have been achieved in a single database call. Nonetheless, it could just be that your technical architect does not want you to use EF and the like. So, you have to revert to code like this... Incidentally, it may also be an idea to decorate each of the properties with attributes for DataAnnotations, etc., but I'm keeping this strictly POCO.

EDIT Fixed for TimeStamp and Guid?

Solution 3:

VB version

declare @TableName sysname = 'myTableName'
declare @prop varchar(max)
PRINT 'Public Class ' + @TableName
declare props cursor for
select distinct ' public property ' + ColumnName + ' AS ' + ColumnType AS prop
from ( 
    select  
        replace(col.name, ' ', '_') ColumnName,  column_id, 
        case typ.name  
            when 'bigint' then 'long' 
            when 'binary' then 'byte[]' 
            when 'bit' then 'boolean' 
            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 'integer' 
            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' 
        end ColumnType 
    from sys.columns col join sys.types typ on col.system_type_id = typ.system_type_id 
    where object_id = object_id(@TableName) 
) t 
order by prop
open props
FETCH NEXT FROM props INTO @prop
WHILE @@FETCH_STATUS = 0
BEGIN
    print @prop
    FETCH NEXT FROM props INTO @prop
END
close props
DEALLOCATE props
PRINT 'End Class'