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79 lines
2.2 KiB
79 lines
2.2 KiB
# -*- coding: utf-8 -*-
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"""Database module, including the SQLAlchemy database object and DB-related
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utilities.
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"""
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from sqlalchemy.orm import relationship
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from .extensions import db
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from .compat import basestring
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# Alias common SQLAlchemy names
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Column = db.Column
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relationship = relationship
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class CRUDMixin(object):
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"""Mixin that adds convenience methods for CRUD (create, read, update, delete)
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operations.
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"""
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@classmethod
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def create(cls, **kwargs):
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"""Create a new record and save it the database."""
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instance = cls(**kwargs)
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return instance.save()
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def update(self, commit=True, **kwargs):
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"""Update specific fields of a record."""
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for attr, value in kwargs.items():
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setattr(self, attr, value)
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return commit and self.save() or self
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def save(self, commit=True):
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"""Save the record."""
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db.session.add(self)
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if commit:
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db.session.commit()
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return self
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def delete(self, commit=True):
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"""Remove the record from the database."""
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db.session.delete(self)
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return commit and db.session.commit()
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class Model(CRUDMixin, db.Model):
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"""Base model class that includes CRUD convenience methods."""
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__abstract__ = True
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# From Mike Bayer's "Building the app" talk
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# https://speakerdeck.com/zzzeek/building-the-app
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class SurrogatePK(object):
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"""A mixin that adds a surrogate integer 'primary key' column named
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``id`` to any declarative-mapped class.
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"""
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__table_args__ = {'extend_existing': True}
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id = db.Column(db.Integer, primary_key=True)
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@classmethod
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def get_by_id(cls, id):
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if any(
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(isinstance(id, basestring) and id.isdigit(),
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isinstance(id, (int, float))),
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):
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return cls.query.get(int(id))
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return None
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def ReferenceCol(tablename, nullable=False, pk_name='id', **kwargs):
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"""Column that adds primary key foreign key reference.
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Usage: ::
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category_id = ReferenceCol('category')
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category = relationship('Category', backref='categories')
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"""
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return db.Column(
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db.ForeignKey("{0}.{1}".format(tablename, pk_name)),
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nullable=nullable, **kwargs)
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