sqlconnection sqlcommand 的用法

sqlconnection sqlcommand 的用法 SqlConnection myConnection = new SqlConnection(ConfigurationManager.ConnectionStrings[SQLCONNECTIONSTRING].ConnectionString); using() 看到一段程序 用到 using(SqlConnection conn = new SqlConnection (connString))好像 类似于 try catch 的功能吧 . SqlConnection Conn=new SqlConnection(connString);是什么意思?SqlDataAdapter da = new SqlDataAdapter(sql,conn);是什么意思其中da代表什么？ 谁能帮我看看那这些代码什么意思?public static SqlConnection createdb(){string dbstring = ConfigurationSettings.AppSettings[cn];SqlConnection conn = new SqlConnection(dbstring);return conn;}public static bool delly(int id){try{SqlConne 参数化查询 需要参数 但未提供该参数.SqlConnection con = new SqlConnection(server=(local);Integrated Security=True;database=varatis); SqlParameter[] str = new SqlParameter[]{ new SqlParameter(@name,SqlDbType.Va 请求各位高手这个函数是什么函数?功能是什么?函数如下：public static DataTable ExecuteDataTable(string s,params SqlParameter[] parameters){using(SqlConnection conn=new SqlConnection(DBCon())){conn.Open();using (SqlCommand scm = 为什么这么简单的问题我都不会?string str = System.Configuration.ConfigurationManager.AppSettings[sqlConnString]; SqlConnection sc = new SqlConnection(str); sc.Open(); string sqls = insert into teacher_info_north(teacher 请问每句代码的意思是什么?public SqlDataReader GetmySend(string username){SqlConnection myConnection = new SqlConnection(ConfigurationManager.AppSettings[MySQLConn]);string cmdText = SELECT * FROM send where name='+username+' ORDER BY C#语句 在线等这解决string connStr = @Data Source=.;Initial Catalog=zmgl;Integrated Security=True;//验证账户密码形式 //创建数据库连接对象 SqlConnection conn = new SqlConnection(connStr); C# 看不懂,public void frmBooksql(){//打开数据库SqlConnection mySqlConnection = new SqlConnection(Conn);mySqlConnection.Open();string sqlQuery = SELECT * FROM Book;SqlCommand mySqlCommand = new SqlCommand(sqlQuery,mySqlConnection);mySqlComma SqlConnection cn = new SqlConnection(conn); cn.Open();string str=update Grade set id=(' + TextBox1.Text.Trim() + ',sn=(' + TextBox2.Text.Trim() + ','+ TextBox3.Text.Trim() + ',' + TextBox4.Text.Trim() + ',' + TextBox5.Text.Trim() + ',' + ADO课程里面的简答题.1.SqlConnection作用及方法 2.SqlCommand作用不能一句话的那种 C#中的Connection.Close()是什么意思?Connection是那个类的属性,属于哪个命名空间?Connection.Close()与ConnectionState.Closed和SqlConnection.Close()的区别? Dim sql As String Dim sqlcn As SqlConnection sqlcn = New SqlConnection sqlcn.ConnectionString = workstation id=SG;packet size=4096;integrated security=SSPI;data source=SG;persis & _ t security info=False;initial catalog=student Dim backstring As 每一句的代码表示什么意思?SqlConnection conn = new SqlConnection();conn.ConnectionString = Data Source=(local);Initial Catalog=news;User ID=sa;Password=123;SqlCommand cmd = new SqlCommand();cmd.Connection = conn;for (int i=0;i ds.Tables[0].Rows.Count > 1 private void button2_Click_1(object sender,EventArgs e){DataSet ds = new DataSet();string consqlserver = Data Source=.;Initial Catalog=留言板;Integrated Security=SSPI;string sql = SELECT * FROM liuyan;SqlConnection 系统报错：嵌入的语句不能是声明或标记语句SqlConnection下有波浪线提示“嵌入的语句不能是声明或标记语句”代码如下：using System;using System.Data;using System.Configuration;using System.Collections;using S