Ajaxian

Monday, April 14th, 2008

Joose expands with new ORM

Category: Gears, JavaScript

Malte has continued to work on Joose, his meta object system for JavaScript. He has added a lot of documentation, including cookbooks that tell the story nicely. He also told us about a feature that is near and dear to my Google heart:

Joose now includes a simple object relational mapper for the Gears database in the examples section. If you have Gears installed, you can run it.

It will run its test suite and then display a class browser that displays the contents of a table for classes that represent a database
tables. The example has two entities (Car and Person in the MyEntities module).

Declaring the entities with this proof-of-concept OR-mapper looks like
this:

PLAIN TEXT

JAVASCRIPT:

1.  
2. Module("MyEntities", function (m) {
3.  
4.    Class("Car", {
5.        isa:  ORM.Entity,
6.  
7.        has: {
8.            owner: {
9.                metaclass: ORM.HasOne,
10.                isa:       function () { return m.Person }
11.            }
12.        },
13.  
14.        classMethods: {
15.            tableName: function () {
16.                return "car"
17.            }
18.        }
19.    })
20.  
21.    Class("Person", {
22.        isa:  ORM.Entity,
23.  
24.        classMethods: {
25.            tableName: function () {
26.                return "person"
27.            }
28.        },
29.  
30.        has: {
31.            mother: {
32.                metaclass: ORM.HasOne,
33.                isa:       function () { return m.Person }
34.            },
35.  
36.            cars: {
37.                metaclass:  ORM.HasMany,
38.                isa:        function () { return m.Car },
39.                foreignKey: "owner"
40.            }
41.        }
42.    });
43. });
44.  

And some example usage:

PLAIN TEXT

JAVASCRIPT:

1.  
2. // Create the mother
3. var mother = new MyEntities.Person();
4. mother.name("elke");
5. mother.city("Elmshorn");
6. mother.save();
7.  
8. // Create the son
9. var person = new MyEntities.Person();
10. person.name("malte");
11. person.city("Hamburg");
12. person.mother(mother); // set the mother
13. person.save();
14.  
15. // Give the son 10 cars :)
16. for(var i = 0; i <10; i++) {
17.     var car = new MyEntities.Car();
18.     car.model("3."+i);
19.     car.brand("bmw");
20.     car.owner(person);
21.     car.save();
22. }
23.  
24. // refetch the person from the db
25. var personFromDb = Entities.Person.newFromId(person.rowid());
26.  
27. alert(personFromDb.mother().name()) // will alert 'elke'
28. alert(personFromDb.cars()[0].brand()) // will alert 'bmw'
29.  

Posted by Dion Almaer at 4:55 am