jdbc练习_update语句和JDBC练习_update、DDL语句

需求：修改一条数据

java代码实例：

Statement statement = null;
        Connection connection = null;
        try {
            Class.forName("com.mysql.cj.jdbc.Driver");
            String sql = "update account set balance = 1006 where id = 3";
            connection = DriverManager.getConnection("jdbc:mysql:///a2", "root", "root");
            statement = connection.createStatement();
            int i = statement.executeUpdate(sql);
            System.out.println(i);
            if (i>0){
                System.out.println("修改成功");
            }else {
                System.out.println("修改失败");
            }
        } catch (ClassNotFoundException | SQLException e) {
            e.printStackTrace();
        }finally {
            if (statement !=null){
                try {
                    statement.close();
                } catch (SQLException e) {
                    e.printStackTrace();
                }
            }
            if (connection !=null){
                try {
                    connection.close();
                } catch (SQLException e) {
                    e.printStackTrace();
                }
            }
        }

 

 

 

 

 

 

 

 

 

 

JDBC练习_update、DDL语句

需求：修改一条数据

java代码实例：

Statement statement = null;
        Connection connection = null;
        try {
            Class.forName("com.mysql.cj.jdbc.Driver");
            String sql = "delete from account where id= 3";
            connection = DriverManager.getConnection("jdbc:mysql:///a2", "root", "root");
            statement = connection.createStatement();
            int i = statement.executeUpdate(sql);
            System.out.println(i);
            if (i>0){
                System.out.println("删除成功");
            }else {
                System.out.println("删除失败");
            }
        } catch (ClassNotFoundException | SQLException e) {
            e.printStackTrace();
        }finally {
            if (statement !=null){
                try {
                    statement.close();
                } catch (SQLException e) {
                    e.printStackTrace();
                }
            }
            if (connection !=null){
                try {
                    connection.close();
                } catch (SQLException e) {
                    e.printStackTrace();
                }
            }
        }

 

 

 

 

使用java代码创建一张表

 Statement statement = null;
        Connection connection = null;
        try {
            Class.forName("com.mysql.cj.jdbc.Driver");
            String sql = "create table student(id int,name varchar(20))";
            connection = DriverManager.getConnection("jdbc:mysql:///a2", "root", "root");
            statement = connection.createStatement();
            int i = statement.executeUpdate(sql);
            System.out.println(i);
        } catch (ClassNotFoundException | SQLException e) {
            e.printStackTrace();
        }finally {
            if (statement !=null){
                try {
                    statement.close();
                } catch (SQLException e) {
                    e.printStackTrace();
                }
            }
            if (connection !=null){
                try {
                    connection.close();
                } catch (SQLException e) {
                    e.printStackTrace();
                }
            }
        }

 

 

 

 

需求：修改一条数据

 

java代码实例：