Module: fields
This module contains DSL statements which allow you to declare which fields (columns) your Elixir entities have. There are currently two different statements that you can use to declare fields:
has_field
The has_field statement allows you to define fields one at a time.
The first argument is the name of the field, the second is its type. Following these, any number of keyword arguments can be specified for additional behavior. The following arguments are supported:
| Argument Name | Description |
|---|---|
| required | Specify whether or not this field can be set to None (left without a value). Defaults to False, unless the field is a primary key. |
| deferred | Specify whether this particular column should be fetched by default (along with the other columns) when an instance of the entity is fetched from the database or rather only later on when this particular column is first referenced. This can be useful when one wants to avoid loading a large text or binary field into memory when its not needed. Individual columns can be lazy loaded by themselves (by using deferred=True) or placed into groups that lazy-load together (by using deferred = "group_name"). |
Any other keyword argument is passed on to the SQLAlchemy Column object. Please refer to the SQLAlchemy Column object's documentation for further detail about which keyword arguments are supported.
Here is a quick example of how to use has_field.
class Person(Entity): has_field('id', Integer, primary_key=True) has_field('name', String(50))
with_fields
The with_fields statement allows you to define fields all at once.
Each keyword argument to this statement represents one field, which should be a Field object. The first argument to a Field object is its type. Following it, any number of keyword arguments can be specified for additional behavior. The with_fields statement supports the same keyword arguments than the has_field statement.
Here is a quick example of how to use with_fields.
class Person(Entity): with_fields( id = Field(Integer, primary_key=True), name = Field(String(50)) )