比如说MSSQL就是System.Data.SqlClient
Oracle就是System.Data.OracleClient
MySql就是MySql.Data.MySqlClient
其它的相应就是的了.还有什么DB2.还有等等一些.
以前我们做跨数据库的时候用的是反射.只不过看到网上好多评论说反射效率不怎么好
所以近来在研究System.Data.Common
也就是通用的数据链接类吧
当然这里只是做测试.没有做太多的封装,这里是我的目录结构
话不多说.上代码
当然第一步还是在web.config里面写上数据链接语句.
这里是最关键的
我这里测试的只有mysql,mssql
<connectionStrings>
<add name="ConnectionString1" connectionString="Data Source=LIUJU;Initial Catalog=MSPetShop4;Persist Security Info=True;User ID=sa;Password=***" providerName="System.Data.SqlClient"/>
<add name="ConnectionString" connectionString="server=localhost;user id=root;password=***;persist security info=True;database=mspetshop4" providerName="MySql.Data.MySqlClient"/>
</connectionStrings>
这里的name你自己设置一个名字就可以了.connectionString就是数据库链接语句.这里没有什么好说的
最主要的就是后面的providerName这里就是写上你数据库要引入的名称空间.这样程序才会知道你用的是什么数据库下面这里我就是写的一个webConfig的帮助类.
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Configuration;
namespace DBHelper.Library
{
public static class WebConfigHelper
{
private readonly static string DBConnectionString = ConfigurationManager.ConnectionStrings["ConnectionString"].ConnectionString;
private readonly static string DBProviderName = ConfigurationManager.ConnectionStrings["ConnectionString"].ProviderName;
public static string GetConnectionString
{
get { return DBConnectionString; }
}
public static string GetProviderName
{
get { return DBProviderName; }
}
}
}
好.下面就是主要的了
using System;
using System.Data;
using System.Data.Common;
using System.Collections.Generic;
using System.Linq;
using System.Text;
namespace DBHelper.Library
{
public static class DataAccessHelper
{
/// <summary>
/// 创建DbCommand对象
/// </summary>
/// <returns>DbCommand对象</returns>
public static DbCommand GetCommand()
{
//得到webConfig里面的要引用的名称空间
string DBProviderName = WebConfigHelper.GetProviderName;
//得到webConfig里面的链接字符串
string DBConnectionString = WebConfigHelper.GetConnectionString;
//数据库工厂类为此数据库创建一个数据库链接对象
DbProviderFactory dpf = DbProviderFactories.GetFactory(DBProviderName);
//创建Connection
DbConnection conn = dpf.CreateConnection();
conn.ConnectionString = DBConnectionString;
//创建Command
DbCommand comm = conn.CreateCommand();
comm.CommandType = CommandType.Text;
return comm;
}
/// <summary>
/// 执行查询，返回datatable
/// </summary>
/// <param name="command"></param>
/// <returns></returns>
public static DataTable ExecuteSelectCommand(DbCommand command)
{
DataTable table;
try
{
if (command.Connection.State != ConnectionState.Open)
{
command.Connection.Open();
}
DbDataReader reader = command.ExecuteReader();
table = new DataTable();
table.Load(reader);
reader.Close();
}
catch (Exception ex)
{
throw new Exception(ex.Message, ex);
}
finally
{
command.Connection.Close();
}
return table;
}
/// <summary>
/// 执行update insert del操作
/// </summary>
/// <param name="command"></param>
/// <returns>返回影响行数</returns>
public static int ExecuteNonQuery(DbCommand command)
{
int affectRows = -1;
try
{
if (command.Connection.State != ConnectionState.Open)
{
command.Connection.Open();
}
affectRows = command.ExecuteNonQuery();
}
catch (Exception ex)
{
throw new Exception(ex.Message, ex);
}
finally
{
command.Connection.Close();
}
return affectRows;
}
/// <summary>
/// 返回第一列第一行
/// </summary>
/// <param name="command"></param>
/// <returns></returns>
public static string ExecuteScalar(DbCommand command)
{
string value = "";
try
{
if (command.Connection.State != ConnectionState.Open)
{
command.Connection.Open();
}
value = command.ExecuteScalar().ToString();
}
catch (Exception ex)
{
throw new Exception(ex.Message, ex);
}
finally
{
command.Connection.Close();
}
return value;
}
}
}
这样你就可以只要配置一下webConfig程序就自动知道你链接的是什么数据库,就可以自动为你创建一个数据库链接对象了.
使用方法
protected void Page_Load(object sender, EventArgs e)
{
DbCommand dc = DataAccessHelper.GetCommand();
dc.CommandText = "SELECT ProductId, CategoryId, Name, Descn FROM Product";
DataTable dt = DataAccessHelper.ExecuteSelectCommand(dc);
GridView1.DataSource = dt;
GridView1.DataBind();
}
运行结果