JDBC练习-update语句以及update，DDL语句

JDBC练习-update语句

account表 修改记录

    public static void main(String[] args) {
        Connection conn = null;
        Statement stat = null;
        try {
            //1.注册驱动
            Class.forName("com.mysql.cj.jdbc.Driver");
            //2.获取连接对象
            conn = DriverManager.getConnection("jdbc:mysql:///db2", "root", "root");
            //3.定义sql语句
            String sql = "update account set balance = 1500 where id = 3";
            //4.获取执行sql语句的对象Statement
            stat = conn.createStatement();
            //5执行sql语句
            int count = stat.executeUpdate(sql);
            //6.处理结果
            System.out.println(count);
            if (count > 0){
                System.out.println("修改成功");
            }else {
                System.out.println("修改失败");
            }
        } catch (ClassNotFoundException e) {
            throw new RuntimeException(e);
        } catch (SQLException e) {
            e.printStackTrace();
        }finally {
            //7.是否资源
            if (stat != null){
                try {
                    stat.close();
                } catch (SQLException e) {
                    e.printStackTrace();
                }
            }
            if (conn != null){
                try {
                    conn.close();
                } catch (SQLException e) {
                    e.printStackTrace();
                }
            }
        }
    }

 

 

JDBC练习-delete，DDL语句

    public static void main(String[] args) {
        Connection conn = null;
        Statement state = null;
        try {
            //注册驱动
            Class.forName("com.mysql.cj.jdbc.Driver");
            //获取连接对象
            conn = DriverManager.getConnection("jdbc:mysql:///db2", "root", "root");
            //定义sql
            String sql = "delete from account where id = 3";
            //获取执行sql对象
            state = conn.createStatement();
            //执行sql
            int count = state.executeUpdate(sql);
            //处理结果
            System.out.println(count);
            if (count > 0 ){
                System.out.println("删除成功");
            }else {
                System.out.println("删除失败");
            }
        } catch (ClassNotFoundException e) {
            throw new RuntimeException(e);
        } catch (SQLException e) {
            throw new RuntimeException(e);
        }finally {
            //释放资源
            if (state != null){
                try {
                    state.close();
                } catch (SQLException e) {
                    throw new RuntimeException(e);
                }
            }
            if (conn != null){
                try {
                    conn.close();
                } catch (SQLException e) {
                    throw new RuntimeException(e);
                }
            }
        }
    }

 

执行DDL语句：

    public static void main(String[] args) {
        Connection conn = null;
        Statement state = null;
        try {
            //注册驱动
            Class.forName("com.mysql.cj.jdbc.Driver");
            //获取连接对象
            conn = DriverManager.getConnection("jdbc:mysql:///db2", "root", "root");
            //定义sql
            String sql = "create table acc1(id int,name varchar(20))";
            //获取执行sql对象
            state = conn.createStatement();
            //执行sql
            int count = state.executeUpdate(sql);
            //处理结果
            System.out.println(count);
        } catch (ClassNotFoundException e) {
            throw new RuntimeException(e);
        } catch (SQLException e) {
            throw new RuntimeException(e);
        }finally {
            //释放资源
            if (state != null){
                try {
                    state.close();
                } catch (SQLException e) {
                    throw new RuntimeException(e);
                }
            }
            if (conn != null){
                try {
                    conn.close();
                } catch (SQLException e) {
                    throw new RuntimeException(e);
                }
            }
        }
    }