如何实现数据库实体生成工具

 

1 原理：

利用 SqlDataReader .GetSchemaTable获取列元数据，然后根据列的元数据生成需要的实体。本程序主要用到了以下三个字段，SchemaTable的其它字段见MSDN.

名称	说明
ColumnName	列的名称；它可能不唯一。如果无法确定该名称，则返回 null 值。此名称始终反映最近对当前视图或命令文本中的列进行的重命名。
DataType	映射到列的 .NET Framework 类型。
AllowDBNull	如果使用者可以将该列设置为 null 值，或者如果提供程序不能确定使用者是否可以将该列设置为 null 值，则设置该值。否则，不设置该值。即使列无法设置为 null 值，它仍可能包含 null 值。

2实现

(1) 表结构

(2) 生成表格的脚本

USE [BPMDB]


GO


/****** 对象: Table [dbo].[PW_User] 脚本日期: 09/03/2011 13:13:06 ******/


SET ANSI_NULLS ON


GO


SET QUOTED_IDENTIFIER ON


GO


CREATE TABLE [dbo].[PW_User](


[ID] [uniqueidentifier] ROWGUIDCOL NOT NULL CONSTRAINT [DF_PW_User_ID] 


DEFAULT (newid()),


[userNo] [nvarchar](50) COLLATE Chinese_PRC_CI_AS NOT NULL,


[password] [nvarchar](255) COLLATE Chinese_PRC_CI_AS NOT NULL,


[lastName] [nvarchar](255) COLLATE Chinese_PRC_CI_AS NOT NULL,


[firstName] [nvarchar](255) COLLATE Chinese_PRC_CI_AS NULL,


[alias] [nvarchar](255) COLLATE Chinese_PRC_CI_AS NULL,


[sex] [nvarchar](255) COLLATE Chinese_PRC_CI_AS NULL,


[birthDate] [datetime] NULL,


[phone] [nvarchar](255) COLLATE Chinese_PRC_CI_AS NULL,


[email] [nvarchar](max) COLLATE Chinese_PRC_CI_AS NULL,


[showRule] [nvarchar](255) COLLATE Chinese_PRC_CI_AS NULL,


[isFreeze] [int] NULL,


CONSTRAINT [PK_PW_User_Id] PRIMARY KEY NONCLUSTERED


(


[ID] ASC


)WITH (PAD_INDEX = OFF, IGNORE_DUP_KEY = OFF) ON [PRIMARY]


) ON [PRIMARY]

(3) 代码

/*******************************************************************


* * Copyright (C) hbb0b0


* * All rights reserved.


* *


* Author: HBB0b0 ([email protected])


* Create Date:2011/9/3 13:00:59


* Description:简单的数据库实体生成工具


* *


* * Date Author Description


* *******************************************************************/


using System;


using System.Collections.Generic;


using System.Linq;


using System.Text;


using System.Data;


using System.Data.Sql;


using System.Data.SqlClient;


using System.Diagnostics;


using System.Configuration;


namespace HBB0b0


{


class Program


{


static void Main(string[] args)


{


using (SqlConnection myConnection = new 


SqlConnection(ConfigurationManager.ConnectionStrings["sqlserver"].ConnectionString))


{


myConnection.Close();


myConnection.Open();


DataTable dt = null;


string tableName = "PW_User";


dt = GetTableSchema(myConnection, tableName);


WriteClassEntity(dt, tableName);


}


Console.Read();


}


/// <summary>


/// 获取指定表的架构


/// </summary>


/// <param name="connection"></param>


/// <param name="tableName"></param>


/// <returns></returns>


private static DataTable GetTableSchema(SqlConnection connection, string 


tableName)


{


using (SqlCommand cmd = connection.CreateCommand())


{


cmd.CommandType = CommandType.Text;


cmd.CommandText = string.Format("select top (1) * from {0} with(nolock) ", 


tableName);


DataTable dt = null;


// using (SqlDataReader read = cmd.ExecuteReader())


{


SqlDataReader read = cmd.ExecuteReader();


dt = read.GetSchemaTable();


}


return dt;


}


}


/// <summary>


/// 生成表对应的实体


/// </summary>


/// <param name="dtSchema"></param>


/// <param name="tableName"></param>


private static void WriteClassEntity(System.Data.DataTable dtSchema, string 


tableName)


{


StringBuilder sb = new StringBuilder();


sb.Append("[Serializable]");


sb.AppendLine();


sb.AppendFormat("public class {0}Entity", tableName);


sb.AppendLine();


sb.AppendLine("{");


foreach (System.Data.DataRow row in dtSchema.Rows)


{


//列名称


DataColumn nameCol = 


dtSchema.Columns[dtSchema.Columns.IndexOf("ColumnName")];


//类型


DataColumn typeCol = 


dtSchema.Columns[dtSchema.Columns.IndexOf("DataType")];


//是否为空


DataColumn allowDBNullCol = 


dtSchema.Columns[dtSchema.Columns.IndexOf("AllowDBNull")];


string symbolCanNull = "";


if (Boolean.Parse(row[allowDBNullCol].ToString()) && 


Type.GetType(row[typeCol].ToString()).IsValueType)


{


symbolCanNull = "?";


}


string info = string.Format("public {0}{1} {2} {3} get; set; {4}",


row[typeCol].ToString(),


symbolCanNull,


row[nameCol].ToString(),


"{", "}");


sb.AppendLine(info);


}


sb.AppendLine("}");


//Trace.Listeners.Remove("myListener");


Console.WriteLine(sb.ToString());


//Trace.Write(sb.ToString());


//Trace.Flush();


}


}


}

(4)运行结果