T4 生成数据库实体类

<#@ template language="C#" debug="True" hostspecific="True" #>
<#@ output extension=".cs" #>
<#@ assembly name="System.Data" #>
<#@ assembly name="System.xml" #>
<#@ import namespace="System.Collections.Generic" #>
<#@ import namespace="System.Data.SqlClient" #>
<#@ import namespace="System.Data" #>
using System;
namespace MyProject.Entities 
{
 <# 
	string connectionString = "Data Source=localhost;Initial Catalog=IntegralDB;User ID=sa;Password=ABcd1234;"; 
	SqlConnection conn = new SqlConnection(connectionString); 
	conn.Open(); 
	System.Data.DataTable schema = conn.GetSchema("TABLES"); 
	string selectQuery = "select * from @tableName"; 
	SqlCommand command = new SqlCommand(selectQuery,conn); 
	SqlDataAdapter ad = new SqlDataAdapter(command); 
	System.Data.DataSet ds = new DataSet();

	string propQuery = "SELECT 表名=sobj.name,字段名=scol.name,字段说明=sprop.[value] FROM syscolumns as scol inner join sys.sysobjects as sobj on scol.id=sobj.id and sobj.xtype='U' and sobj.name<>'dtproperties' left join sys.extended_properties as sprop on scol.id=sprop.major_id and scol.colid=sprop.minor_id where sobj.name='@tableName' and scol.name='@columnName'"; 
	SqlCommand command2 = new SqlCommand(propQuery,conn); 
	SqlDataAdapter ad2 = new SqlDataAdapter(command2); 
	System.Data.DataSet ds2 = new DataSet();

	foreach(System.Data.DataRow row in schema.Rows) 
	{  #>   
		/// <summary>
		/// 数据表实体类：<#= row["TABLE_NAME"].ToString() #>Info 
		/// </summary>
		[Serializable()]
		public class <#= row["TABLE_NAME"].ToString() #>Info
		{    <#
			ds.Tables.Clear();
			command.CommandText = selectQuery.Replace("@tableName",row["TABLE_NAME"].ToString()); 
			ad.FillSchema(ds, SchemaType.Mapped, row["TABLE_NAME"].ToString());
			foreach (DataColumn dc in ds.Tables[0].Columns)
			{ 
			#>
			<# 
			 ds2.Tables.Clear();
			 command2.CommandText = propQuery.Replace("@tableName",row["TABLE_NAME"].ToString()); 
			 command2.CommandText = command2.CommandText.Replace("@columnName",dc.ColumnName); 
			 ad2.Fill(ds2);
			#> 
			/// <summary>
			/// <#= dc.DataType.Name #>:<#=ds2.Tables[0].Rows[0].ItemArray[2]#>
			/// </summary>				       
			public <#= dc.DataType.Name #> <#= dc.ColumnName #> {get;set;}       
	<# }  #>   
	}            
	<# 
	} #>  
}

select b.[value] from sys.columns a left join sys.extended_properties b on a.object_id=b.major_id
and a.column_id=b.minor_id inner join sysobjects c on a.column_id=c.id
and a.[name]='列名' and c.[name]='表名'

实例：

SELECT
表名=case when a.colorder=1 then d.name else '' end,
表说明=case when a.colorder=1 then isnull(f.value,'') else '' end,
字段序号=a.colorder,
字段名=a.name,
标识=case when COLUMNPROPERTY( a.id,a.name,'IsIdentity')=1 then '√'else '' end,
主键=case when exists(SELECT 1 FROM sysobjects where xtype='PK' and name in (
SELECT name FROM sysindexes WHERE indid in(
SELECT indid FROM sysindexkeys WHERE id = a.id AND colid=a.colid
))) then '√' else '' end,
类型=b.name,
占用字节数=a.length,
长度=COLUMNPROPERTY(a.id,a.name,'PRECISION'),
小数位数=isnull(COLUMNPROPERTY(a.id,a.name,'Scale'),0),
允许空=case when a.isnullable=1 then '√'else '' end,
默认值=isnull(e.text,''),
字段说明=isnull(g.[value],'')
FROM syscolumns a
left join systypes b on a.xusertype=b.xusertype
inner join sysobjects d on a.id=d.id and d.xtype='U' and d.name<>'dtproperties'
left join syscomments e on a.cdefault=e.id
left join sys.extended_properties g on a.id=g.major_id and a.colid=g.minor_id
left join sys.extended_properties f on d.id=f.major_id and f.minor_id=0
--where d.name='orders' --如果只查询指定表,加上此条件
order by a.id,a.colorder