JDBC学习小结

数据库：DATABASE

表： TABLE

字段： 属性

[code]    //链接数据库的驱动
    String driver="com.mysql.jdbc.Driver";
    //URL指向要访问的数据库名
    String url="jdbc:mysql://localhost:3306/clazz";//固定格式
    //MySQL配置时的用户名
    String user="root";
    //java链接MySQl配置时的密码
    String password="123456";
    try {
        Class.forName(driver);//加载驱动
        connection= DriverManager.getConnection(url, user, password);
     state=connection.createStatement();//出错，没有建statement
     }//后半部分省略

JDBC的SQL语句：

创建表：

[code]String creattable="Create table if not exists user (id int primary key auto_increment,user_name varchar(30) binary NOT NULL,passerword varchar(30) NOT NULL)";
            state.execute(creattable);

binary//用于区分大小写

增：insert into tablename

Demo：insert into student (name,sex,age)values(‘李四’,1,23)

删：delete from xxx where xxx

Demo：delete from student where name=’张三’

改：update xxx set = = where

Demo：update student set age=19,sex=1 where id=10

查：select * from xxx where

Demo：select name,age from student where age>20

预编译：

Connection con=DriverManager(……);

preparestatement pre=con.preparedstatement(sql语句);

pre.setString(1,参数);

ResultSet set=pre.executeQuery();

事务:

事务（一组不可拆分的操作）//银行ATM 提款机 输入金额—播放录音—打开取钱口-吐钱-钱拿走

[code]String insert1="insert into user (user_name,passerword)values('bcdhuj','bfhr')";
String insert2="insert into user (user_name,passerword)values('bcdhujcdcd','bfhrcd')";
String insert3="insert into user (user_name,passerwords)values('bcd','bfd')";
String insert4="insert into user (user_name,passerword)values('bcdhcdcd','bfcd')";
Connection conn=RegisterTest.newInstance().getConnection();
try {
                Statement state=conn.createStatement();
//不自动提交，只有等所有语句都运行完才能进行提交
                conn.setAutoCommit(false);
                state.execute(insert1);
                state.execute(insert2);
                state.execute(insert3);
                state.execute(insert4);
                conn.commit();
            } catch (SQLException e) {
                e.printStackTrace();
                }