Crecto::Model

Last updated 9 months ago
Application data models should inherit from Crecto::Model
class User < Crecto::Model
The Crecto::Model class imposes the inherited which imports the correct schema modules and sets up class wide variables and constants used for keeping track of associations and field names.
Schema
Inside the data model is where the database schema is defined.
class User < Crecto::Model
    schema "users" do
        field :first_name, String
        field :last_name, String
    end
end
The shema macro takes one argument and an options tuple. The argument is the database table name. If your database table doesn't have a primary key, you can pass an option to disable it: schema "users", primary_key: false do
Default fields
By default Crecto assumes your table has the following column names defined id, created_at, and updated_at.
These can be easily overridden.
class User < Crecto::Model
    set_created_at_field :other_field_name
    set_updated_at_field nil # This table does not use an updated at field
​
    # This table does not have a primary key field
    schema "users", primary_key: false do
        # fields...
    end
end
Fields
Database table fields are defined using the field macro. The field macro takes 2 arguments, the column name as a Symbol and the column type, and an optional options tuple.
Field types
Int
field :first_field, Int32
field :second_field, Int64
field :third_field, Int16
Float
field :first_field, Float32
field :second_field, Float64
Bool
field :bool_field, Bool
String
field :string_field, String
Time
field :time_field, Time
Array, postgres only
field :first_field, Array(Int32)
field :second_field, Array(Float64)
field :third_field, Array(Bool)
field :fourth_field, Array(String)
Arrays can be queries using build-in postgres methods
Repo.all(User, Query.where("? = ANY(fourth_field)", "some_string"))
Json, postgres only
field :json_field, Json
Json fields can be both postgres json or jsonb types. If jsonb is used, those fields can be queried using build-in postgres methods.
Repo.all(User, Query.where("json_field @> '{\"test\": \"123\"}'")
Field options
class User < Crecto::Model    
    # primary_key : Specify a new primary key field
    field :uuid, String, primary_key: true
​
    # virtual : This field does not exist in the database and wont be pesisted.
    # but can be set and accessed on the model instance
    field :password_confirm, String, virtual: true
​
    # default : Specify a default value for the attribute
    field :is_admin, Bool, default: false
end
Enum fields
class Vehicle < Crecto::Model
    enum State
        OFF
        STARTING
        RUNNING
    end
​
    enum Make
        COUPE
        SEDAN
        HATCH
        TRUCK
    end
​
    schema "vehicles" do
        enum_field :state, State
        enum_field :make, Make, column_name: "vehicle_type", column_type: Int32
    end
end
Non-nillable attributes
If you with to access attributes of a model without having to check for nil, in the case that you are using a NOT NULL database constraint you can use the non-nillable attribute accessors.
CAUTION: Mis-use of this could lead to Nil reference runtime exceptions
user.age!
user.name!
Getting Started
Validations