C# 连接SQLServer-Ado.net

S1:C#引入命名空间

using system.data;

using system.data.sqlclient;

S2:引用ado.net相关类对象

SQLconnection

string connstring = "Server=.;DataBase=StudentManageDB;User Id=sa;Password=xxx";

sqlconnection  sqlconnection conn = new sqlconnection(connstring);

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sqlconnection  sqlconnection conn = new sqlconnection();

//不写参数，则要设定connectionstring属性

方法：

open();

close();

判断数据库是否连接成功：

ConnectionState.Open == conn.State

SQLcommand

sqlcommand cmd = new sqlcommand(sql,conn)

sql为insert、update、delete语句

conn为sqlconnection对象

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sqlcommand cmd = new sqlcommand()

//不写参数，则要设定commandtext、connection属性

方法：

ExecuteNonQuery();执行sql方法，返回值：-1表示更新失败，0表示没有任何更新，>1表示更新成功

ExecuteScalar();可以单独执行select；也可以执行insert。。。；select @@identity，查出刚刚执行的insert后，数据库分配的标识列生成的值。但是该方法返回object类型，需要转化。@@xxx,表示数据库的全局变量，只能调用，不能更改

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

namespace DBConnection
{
    class Program
    {
        static void Main(string[] args)
        {
            #region insert command
            //创建连接字符串
            string connString = "Server=.;DataBase=StudentManageDB;User Id=sa;Password=123456";
            //创建数据库连接数据库对象
            SqlConnection conn = new SqlConnection(connString);
            //conn.ConnectionString = connString;
            StringBuilder sqlBuilder = new StringBuilder();
            sqlBuilder.Append("insert into StudentClass(ClassId,ClassName) values({0},'计算机一班')");
            string sql1 = string.Format(sqlBuilder.ToString(),1);
            sqlBuilder.Clear();
            sqlBuilder.Append("insert into Students(StudentName,Age,Gender,Birthday,StudentIdNo,StudentAddress,PhoneNumber,ClassId)");
            sqlBuilder.Append(" values('{0}',{1},'{2}','{3}',{4},'{5}','{6}',{7})");
            string sql2 = string.Format(sqlBuilder.ToString(), "王烈", 25, "男", "1990-11-21", 122321199011211012, "", "15200012322", 1);
            sqlBuilder.Clear();
            sqlBuilder.Append("insert into Students(StudentName,Age,Gender,Birthday,StudentIdNo,StudentAddress,PhoneNumber,ClassId)");
            sqlBuilder.Append(" values('{0}',{1},'{2}','{3}',{4},'{5}','{6}',{7})");
            string sql3 = string.Format(sqlBuilder.ToString(), "小花", 23, "女", "1995-01-18", 122321199501181012, "", "15200012322", 1);
            sqlBuilder.Clear();
            sqlBuilder.Append("insert into Students(StudentName,Age,Gender,Birthday,StudentIdNo,StudentAddress,PhoneNumber,ClassId)");
            sqlBuilder.Append(" values('{0}',{1},'{2}','{3}',{4},'{5}','{6}',{7})");
            string sql4 = string.Format(sqlBuilder.ToString(), "小猪", 24, "男", "1993-4-28", 122321199304281012, "", "15200012322", 1);
            sqlBuilder.Clear();
            string Sql = sql1 + ";" + sql2 + ";" + sql3 + ";" + sql4;
            //创建cmd对象
            SqlCommand cmd = new SqlCommand(Sql, conn);
            //cmd.CommandText = sql;
            //cmd.Connection = conn;
            //打开数据库
            conn.Open();
            //执行SQL
            int result = cmd.ExecuteNonQuery();
            //关闭数据库
            conn.Close();
            if (4 == result)
                Console.WriteLine("insert OK");
            else
                Console.WriteLine("insert fail");
            Console.ReadLine();

            #endregion

            #region update command
            ////数据库连接字符串
            //string connString = "Server=.;DataBase=StudentManageDB;Uid=sa;Pwd=123456";
            ////创建连接对象
            //SqlConnection conn = new SqlConnection(connString);
            ////sql
            //string sql = "update Students set Age = {0} where StudentId = {1}";
            //sql = string.Format(sql, 24, 10003);
            ////创建cmd对象
            //SqlCommand cmd = new SqlCommand(sql, conn);
            ////打开数据库
            //conn.Open();
            ////exec
            //int result = cmd.ExecuteNonQuery();
            ////关闭数据库
            //conn.Close();
            //if (1 == result)
            //    Console.WriteLine("update OK");
            //else
            //    Console.WriteLine("update fail");
            //Console.ReadLine();
            #endregion

            #region delete command
            ////创建连接字符串
            //string connString = "Server=localhost;DataBase=StudentManageDB;Uid=sa;Pwd=123456";
            ////创建连接对象
            //SqlConnection conn = new SqlConnection(connString);
            ////创建SQL语句
            //string sql = "delete from Students where StudentId = {0}";
            //sql = string.Format(sql, 10003);
            ////创建cmd执行对象
            //SqlCommand cmd = new SqlCommand(sql, conn);
            ////打开数据库
            //conn.Open();
            //int result = cmd.ExecuteNonQuery();
            //conn.Close();
            //if (1 == result)
            //    Console.WriteLine("delete success");
            //else
            //    Console.WriteLine("delete fail");
            //Console.ReadLine();
            #endregion

            if(ConnectionState.Open == conn.State)
            {

            }
        }
    }
}