java和mysql之间的各种数据更新语句说明
import java.sql.Connection;import java.sql.DriverManager; //数据库设计模式在后面的附加图片import java.sql.ResultSet;import java.sql.SQLException;import java.sql.Statement;public class test { public static void main(String args[]) throws ClassNotFoundException, SQLException{ String driver = "com.mysql.jdbc.Driver";String url = "jdbc:mysql://localhost:3306/test";String user = "root";String password = "123456";Connection conn = null;Statement statement = null;ResultSet res = null;String sql = "select * from students";Class.forName(driver);conn = DriverManager.getConnection(url, user, password);statement = conn.createStatement();System.out.println("更新前的数据库：");res = statement.executeQuery(sql);while(res.next()){System.out.println(res.getString("sno")+"\t"+res.getString("sname")+"\t"+res.getString("ssex")+"\t"+res.getString("sdept"));}String insertsql2 ="insert into students values (162,'zhgng9','m','computer')"; //更新语句 add 注意更新时主键不能够重复statement.executeUpdate(insertsql2); System.out.println("更新后的数据库：");res = statement.executeQuery(sql);while(res.next()){System.out.println(res.getString("sno")+"\t"+res.getString("sname")+"\t"+res.getString("ssex")+"\t"+res.getString("sdept"));}//MySQL 语法//SELECT column_name(s)//FROM table_name//LIMIT numberSystem.out.println("只要数据库中的前3行记录：");String sql2 = "select * from students limit 3"; //写法比较好 这是mysql的写法 其他的数据库写法不同res = statement.executeQuery(sql2);while(res.next()){System.out.println(res.getString("sno")+"\t"+res.getString("sname")+"\t"+res.getString("ssex")+"\t"+res.getString("sdept"));}//UPDATE 表名称 SET 列名称 = 新值 WHERE 列名称 = 某值System.out.println("修改数据库中的记录：");sql2 = "update students set sname = 'guang' where sno=160"; // 更新语句的写法statement.executeUpdate(sql2); //这个地方是更新语句res = statement.executeQuery(sql); //这个是查询语句while(res.next()){System.out.println(res.getString("sno")+"\t"+res.getString("sname")+"\t"+res.getString("ssex")+"\t"+res.getString("sdept"));}//DELETE FROM 表名称 WHERE 列名称 = 值System.out.println("删除数据库中的记录：");insertsql2 ="delete from students where ssex='n'"; //删除语句statement.executeUpdate(insertsql2); res = statement.executeQuery(sql); //这个是查询语句while(res.next()){System.out.println(res.getString("sno")+"\t"+res.getString("sname")+"\t"+res.getString("ssex")+"\t"+res.getString("sdept"));}if(!conn.isClosed()){conn.close();} }}