Db+Record Model original created by JFinal

Db class and related Record class provide richer database operations beyond Model class. When using Db and Record classes,mapping to tables in database is no longer necessary. Record is equivalent to generic Model. The commonly-used usage of Db + Record model are shown as follows:

// Create an record, whose name attribute is James and age attribute is 25,and add into database.
Record user = new Record().set("name", "James").set("age", 25);
Db.save("user", user);

// Delete the `User` whose id is 25
Db.deleteById("user", 25);

// Retrive the User, whose id is 25, and modify name attribute to James and update into database.
user = Db.findById("user", 25).set("name", "James");
Db.update("user", user);

// Retrive the User whose id is 25 and only need name and age attributes.
user = Db.findById("user", 25, "name, age");

// Get the name attribute of user.
String userName = user.getStr("name");

// Get the age attribute of user.
Integer userAge = user.getInt("age");

// Retrive all the users whose age are grater than 18.
List<Record> users = Db.find("select * from user where age > 18");

// Paged query the users whose age are greater than 18,in the conditions where current page number id 1 and 10 users per page.
Page<Record> userPage = Db.paginate(1, 10, "select *", "from user where http://ww
age > ?", 18);

The usage of transaction is shown as bellow:

boolean succeed = Db.tx(new IAtom(){
    public boolean run() throws SQLException {
        int count = Db.update("update account set cash = cash - ? where id = ?", 100, 123);
        int count2 = Db.update("update account set cash = cash + ? where id = ?", 100, 456);
        return count == 1 && count2 == 1; }});

The two operations of upgrading database are executed in one transaction and if any exception takes place or false returned by invoke() method, this trasaction would rollback automatically.