SQLHelper类

Posted 2020-06-14

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

 
    /// <summary>
    /// sql server数据操作的底层类
    /// </summary>
    public class SQLHelper
    {
        public static string connStr = System.Configuration.ConfigurationManager.AppSettings["connStr"];

        //1.查询列表 GetTable
        /// <summary>
        /// 查询命令(sql 语句或过程名),返回一个数据表
        /// </summary>
        /// <param name="cmdText">命令</param>
        /// <param name="type">命令类型</param>
        /// <param name="pms">sql参数</param>
        /// <returns></returns>
        public static DataTable GetTable(string cmdText,CommandType type, params SqlParameter[] pms)
        {
            SqlConnection conn = new SqlConnection(connStr);
            conn.Open();
            SqlCommand cmd = new SqlCommand(cmdText, conn);
            cmd.CommandType = type;
            if (pms != null) //判断是不是有参数传递进来 判断数组是不是null
            {
                foreach (SqlParameter item in pms)
                {
                    if (item != null) //判断数组中的每一个元素是不是为null
                    {
                        cmd.Parameters.Add(item);
                    }
                }
            }
            SqlDataAdapter sda = new SqlDataAdapter(cmd);
            DataSet ds = new DataSet();
            sda.Fill(ds, "aa");
            conn.Close();
            //返回结果
            DataTable dt = ds.Tables["aa"];
            return dt;
            //************************************
        }

        //给查询列表操作写一个执行sql语句的重载
        /// <summary>
        /// 执行sql语句，返回数据表
        /// </summary>
        /// <param name="sql">sql语句</param>
        /// <param name="pms">sql语句所需要的参数</param>
        /// <returns></returns>
        public static DataTable GetTable(string sql, params SqlParameter[] pms)
        {
            return GetTable(sql, CommandType.Text, pms);
        }

        //2.执行命令返回影响行数 ExecuteNonQuery
        public static int ExecuteNonQuery(string cmdText, CommandType type, params SqlParameter[] pms)
        {
            SqlConnection conn = new SqlConnection(connStr);
            conn.Open();
            SqlCommand cmd = new SqlCommand(cmdText, conn);
            cmd.CommandType = type;
            if (pms != null) //判断是不是有参数传递进来 判断数组是不是null
            {
                foreach (SqlParameter item in pms)
                {
                    if (item != null) //判断数组中的每一个元素是不是为null
                    {
                        cmd.Parameters.Add(item);
                    }
                }
            } 
            int i = cmd.ExecuteNonQuery();
            conn.Close(); 
            return i;
        }

        public static int ExecuteNonQuery(string sql, params SqlParameter[] pms)
        {
            return ExecuteNonQuery(sql, CommandType.Text, pms);
        }

        //3.查询返回结果中的首行首列  ExecuteSingle
        public static object ExecuteSingle(string cmdText, CommandType type, params SqlParameter[] pms)
        {
            SqlConnection conn = new SqlConnection(connStr);
            conn.Open();
            SqlCommand cmd = new SqlCommand(cmdText, conn);
            cmd.CommandType = type;
            if (pms != null) //判断是不是有参数传递进来 判断数组是不是null
            {
                foreach (SqlParameter item in pms)
                {
                    if (item != null) //判断数组中的每一个元素是不是为null
                    {
                        cmd.Parameters.Add(item);
                    }
                }
            }

            object obj= cmd.ExecuteScalar();
            conn.Close();
            return obj;
        }

        public static object ExecuteSingle(string sql, params SqlParameter[] pms)
        {
            return ExecuteSingle(sql, CommandType.Text, pms);
        }

        //4.查询返回一个DataReader对象,让别人以游标的方式去读取数据  GetDataReader
        public static SqlDataReader GetDataReader(string cmdText, CommandType type, params SqlParameter[] pms)
        {
            SqlConnection conn = new SqlConnection(connStr);
            conn.Open();
            SqlCommand cmd = new SqlCommand(cmdText, conn);
            cmd.CommandType = type;
            if (pms != null) //判断是不是有参数传递进来 判断数组是不是null
            {
                foreach (SqlParameter item in pms)
                {
                    if (item != null) //判断数组中的每一个元素是不是为null
                    {
                        cmd.Parameters.Add(item);
                    }
                }
            }
            SqlDataReader dr = cmd.ExecuteReader(CommandBehavior.CloseConnection);
            return dr;
        }

        public static SqlDataReader GetDataReader(string sql, params SqlParameter[] pms)
        {
            return GetDataReader(sql, CommandType.Text, pms);
        }
        
    }