plink

plink is a persistence link layer with minimal addition to your existing code.

Preparation

Adapters

To use plink, you need to instantiate a database adapter. This adapter should then be passed to a ModelRepository object, which takes care of the most important things for you. An example:

var adapter = new PostgresAdapter(
  "postgres://<username>:<password>@<host>:<port>/<database>");
  
var repo = new ModelRepository.global(adapter);

Subclassing

If you want to be able to persist your class, it's as easy as that:

class Name extends Model {
  String firstName;
  String lastName;
  
  Name();
}

Each subclass needs a default constructor for plink to instantiate a default instance. If you don't want to use the default constructor as plinks default constructor, you can also define a named constructor and annotate defaultConstructor for plink to use:

class Name extends Model {
  String firstName;
  String lastName;
  
  Name(this.firstName, this.lastName);
  
  @defaultConstructor
  Name.def();
}

By extending from Model, your class automatically inherits the properties id, created_at and updated_at, which then are automatically set by the so called ModelRepository when needed. If you now wonder: "Which field types does plink support?" - The answer is quite satisfactory: It supports (nearly) all types of Dart: Maps, Lists, other Objects, ints, Strings and so on.

class Person {
  DateTime birthDate;
  Name name;
  
  Person(this.name, this.birthDate);
  
  @defaultConstructor
  Person.def();
}

Functionality

Saving

To persist such a Name object, instantiate it and then call the ModelRepository.save() method. This returns a Future which completes with the saved instance. Save also saves nested models.

Deleting

Deletion of model instances works the same way and only differs by returning a Future which completes with null. To delete, call the ModelRepository.delete function with your model.

Finding by id

To find a model by its id, you have to call the find(Type type, int id) method on the ModelRepository object (type should be the type of the desired object, in the previously mentioned case it would be Name). This returns a future with the desired model.

Finding by specific criteria

A list of model instances can be fetched by using the ModelRepository.where method. This method takes a type and a so called WhereStatement. These statements can be created with ease, an example would be:

repo.where(TestClass, c("name").eq("Test"))

Currently supported matchers here are equals, not equals, greater than, less than, greater than or equals and less than or equals.

Pull requests are highly appreciated!

Libraries

plink.postgres_adapter