sql连接数据库封装

using System;
using System.Data;
using System.Data.SqlClient;
using System.Configuration;

namespace aoguan.classes.Db
{
/// <summary>
/// DbAccess 的摘要说明。
/// </summary>
public class DbAccess
{
SqlConnection conn;
SqlCommand cmd;
public DbAccess()
{
conn = new SqlConnection(System.Configuration.ConfigurationSettings.AppSettings["connstring"].Trim().ToString());
cmd = new SqlCommand();
cmd.Connection=conn;
}
public DataSet GetSet(string sql)
{
cmd.CommandText=sql;
SqlDataAdapter da = new SqlDataAdapter();
da.SelectCommand=cmd;
DataSet ds = new DataSet();
da.Fill(ds);
return ds;

}
public DataTable GetTable(string sql)
{
cmd.CommandText=sql;
SqlDataAdapter da = new SqlDataAdapter();
da.SelectCommand=cmd;
DataTable dt = new DataTable();
da.Fill(dt);
return dt;
}
//分页的数据
public DataTable GetPerTable(string sql,int cur,int size)
{
cur = (cur-1<1)?(1):(cur);
cmd.CommandText=sql;
SqlDataAdapter da = new SqlDataAdapter();
da.SelectCommand=cmd;
//DataTable dt = new DataTable();
DataSet ds = new DataSet();
da.Fill(ds,(cur-1)*size,size,"per");
return ds.Tables["per"];
}
public int GetState(string sql)
{
int count = 0;
cmd.CommandText=sql;
try
{
conn.Open();
count = cmd.ExecuteNonQuery();
conn.Close();
}
catch(Exception ex)
{
return 0;
}

return count;
}
public int GetReTran(params string[] sql)
{
int count = 0;
conn.Open();
SqlTransaction tran = conn.BeginTransaction();
cmd.Transaction=tran;
foreach(string str in sql)
{
try
{
cmd.CommandText=str;
cmd.ExecuteNonQuery();
}
catch(Exception ex)
{
tran.Rollback();
return 0;
}
count++;

}
tran.Commit();
conn.Close();
return count;

}
}
}