SQLAlchemy patterns

Coaster provides a number of mixin classes for SQLAlchemy models. To use in your Flask app:

from flask import Flask
from flask.ext.sqlalchemy import SQLAlchemy
from coaster.sqlalchemy import BaseMixin

app = Flask(__name__)
db = SQLAlchemy(app)

class MyModel(BaseMixin, db.Model):
    __tablename__ = 'my_model'

Mixin classes must always appear before db.Model in your model’s base classes.

class coaster.sqlalchemy.IdMixin[source]

Provides the id primary key column

class coaster.sqlalchemy.TimestampMixin[source]

Provides the created_at and updated_at audit timestamps

class coaster.sqlalchemy.PermissionMixin[source]

Provides the permissions() method used by BaseMixin and derived classes

permissions(user, inherited=None)[source]

Return permissions available to the given user on this object

class coaster.sqlalchemy.UrlForMixin[source]

Provides a placeholder url_for() method used by BaseMixin-derived classes

class coaster.sqlalchemy.BaseMixin[source]

Base mixin class for all tables that adds id and timestamp columns and includes stub permissions() and url_for() methods

class coaster.sqlalchemy.BaseNameMixin(*args, **kw)[source]

Base mixin class for named objects

class coaster.sqlalchemy.BaseScopedNameMixin(*args, **kw)[source]

Base mixin class for named objects within containers. When using this, you must provide an model-level attribute “parent” that is a synonym for the parent object. You must also create a unique constraint on ‘name’ in combination with the parent foreign key. Sample use case in Flask:

class Event(BaseScopedNameMixin, db.Model):
    __tablename__ = 'event'
    organizer_id = db.Column(db.Integer, db.ForeignKey('organizer.id'))
    organizer = db.relationship(Organizer)
    parent = db.synonym('organizer')
    __table_args__ = (db.UniqueConstraint('name', 'organizer_id'),)
permissions(user, inherited=None)[source]

Permissions for this model, plus permissions inherited from the parent.

class coaster.sqlalchemy.BaseIdNameMixin(*args, **kw)[source]

Base mixin class for named objects with an id tag.

class coaster.sqlalchemy.BaseScopedIdMixin(*args, **kw)[source]

Base mixin class for objects with an id that is unique within a parent. Implementations must provide a ‘parent’ attribute that is either a relationship or a synonym to a relationship referring to the parent object, and must declare a unique constraint between url_id and the parent. Sample use case in Flask:

class Issue(BaseScopedIdMixin, db.Model):
    __tablename__ = 'issue'
    event_id = db.Column(Integer, db.ForeignKey('event.id'))
    event = db.relationship(Event)
    parent = db.synonym('event')
    __table_args__ = (db.UniqueConstraint('url_id', 'event_id'),)
permissions(user, inherited=None)[source]

Permissions for this model, plus permissions inherited from the parent.

class coaster.sqlalchemy.BaseScopedIdNameMixin(*args, **kw)[source]

Base mixin class for named objects with an id tag that is unique within a parent. Implementations must provide a ‘parent’ attribute that is a synonym to the parent relationship, and must declare a unique constraint between url_id and the parent. Sample use case in Flask:

class Event(BaseScopedIdNameMixin, db.Model):
    __tablename__ = 'event'
    organizer_id = db.Column(db.Integer, db.ForeignKey('organizer.id'))
    organizer = db.relationship(Organizer)
    parent = db.synonym('organizer')
    __table_args__ = (db.UniqueConstraint('url_id', 'organizer_id'),)
class coaster.sqlalchemy.JsonDict(*args, **kwargs)

Represents a JSON data structure. Usage:

column = Column(JsonDict)
impl

alias of TEXT

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