dbhelper.cs

客户关系管理系统 客户关系管理系统

using System;
using System.Collections.Generic;
using System.Text;
using System.Data;
using System.Data.SqlClient;

namespace MyCRM.DBUtility
{
    public class DBHelper
    {
        private static SqlConnection connection;
        //连接数据库
        public static SqlConnection Connection
        {
            get
            {
                string sqlCon = "server=(local);database=crm;uid=sa;pwd=;";
                if (connection == null)
                {
                    connection = new SqlConnection(sqlCon);
                    connection.Open();
                }
                else if (connection.State == ConnectionState.Closed)
                {
                    connection.Open();
                }
                else if (connection.State == ConnectionState.Broken)
                {
                    connection.Close();
                    connection.Open();
                }
                return connection;
            }
        }

        //执行不带参数的非查询语句
        public static int ExecuteCommand(string sql)
        {
            SqlCommand scmd = new SqlCommand(sql, Connection);
            int row = scmd.ExecuteNonQuery();
            return row;
        }

        //执行带参数的非查询语句
        public static int ExecuteCommand(string sql, params SqlParameter[] values)
        {
            SqlCommand scmd = new SqlCommand(sql, Connection);
            scmd.Parameters.AddRange(values);
            int row = scmd.ExecuteNonQuery();
            return row;
        }

        //执行不带参数的查询语句
        public static SqlDataReader GetReader(string sql)
        {
            SqlCommand scmd = new SqlCommand(sql, Connection);
            SqlDataReader reader = scmd.ExecuteReader();
            return reader;
        }

        //执行带参数的查询语句
        public static SqlDataReader GetReader(string sql, params SqlParameter[] values)
        {
            SqlCommand scmd = new SqlCommand(sql, Connection);
            scmd.Parameters.AddRange(values);
            SqlDataReader reader = scmd.ExecuteReader();
            return reader;
        }

        //执行不带参数的判断是否有查询结果的语句
        public static int GetScalar(string safeSql)
        {
            SqlCommand cmd = new SqlCommand(safeSql, Connection);
            int result = Convert.ToInt32(cmd.ExecuteScalar());
            return result;
        }

        //执行带参数的判断是否有查询结果的语句
        public static int GetScalar(string safeSql, params SqlParameter[] values)
        {
            SqlCommand cmd = new SqlCommand(safeSql, Connection);
            cmd.Parameters.AddRange(values);
            int result = Convert.ToInt32(cmd.ExecuteScalar());
            return result;
        }

        //此方法用于以DataTable形式返回多条查询结果
        public static DataTable GetDataSet(string sql)
        {
            SqlDataAdapter sda = new SqlDataAdapter(sql, Connection);
            DataSet ds = new DataSet();
            sda.Fill(ds);
            return ds.Tables[0];
        }
    }
}