sqlHelper 帮助类
using System; using System.Collections.Generic; using System.Configuration; using System.Data; using System.Data.SqlClient; using System.Linq; using System.Text; using System.Threading.Tasks; namespace UpdateUserId_ConsoleApp { class sqlHelper { public static string GetSqlConnectionString() { return ConfigurationManager.ConnectionStrings["sqlConnection"].ToString(); } //适合增删改操作,返回影响条数 public static int ExecuteNonQuery(string sql, params SqlParameter[] parameters) { using (SqlConnection conn = new SqlConnection(GetSqlConnectionString())) { using (SqlCommand comm = conn.CreateCommand()) { try { conn.Open(); comm.CommandText = sql; comm.Parameters.AddRange(parameters); return comm.ExecuteNonQuery(); } catch (Exception ex) { throw new Exception(ex.Message); } finally { if (conn != null && conn.State != ConnectionState.Closed) conn.Close(); } } } } //查询操作,返回查询结果中的第一行第一列的值 public static object ExecuteScalar(string sql, params SqlParameter[] parameters) { using (SqlConnection conn = new SqlConnection(GetSqlConnectionString())) { using (SqlCommand comm = conn.CreateCommand()) { try { conn.Open(); comm.CommandText = sql; comm.Parameters.AddRange(parameters); return comm.ExecuteScalar(); } catch (Exception ex) { throw new Exception(ex.Message); } finally { if (conn != null && conn.State != ConnectionState.Closed) conn.Close(); } } } } //Adapter调整,查询操作,返回DataTable public static DataTable ExecuteDataTable(string sql, params SqlParameter[] parameters) { using (SqlDataAdapter adapter = new SqlDataAdapter(sql, GetSqlConnectionString())) { DataTable dt = new DataTable(); adapter.SelectCommand.Parameters.AddRange(parameters); adapter.Fill(dt); return dt; } } public static SqlDataReader ExecuteReader(string sqlText, params SqlParameter[] parameters) { //SqlDataReader要求,它读取数据的时候有,它独占它的SqlConnection对象,而且SqlConnection必须是Open状态 SqlConnection conn = new SqlConnection(GetSqlConnectionString());//不要释放连接,因为后面还需要连接打开状态 SqlCommand cmd = conn.CreateCommand(); conn.Open(); cmd.CommandText = sqlText; cmd.Parameters.AddRange(parameters); //CommandBehavior.CloseConnection当SqlDataReader释放的时候,顺便把SqlConnection对象也释放掉 return cmd.ExecuteReader(CommandBehavior.CloseConnection); } } }