Flask-admin, editing relationship giving me object representation of Foreign Key object

Question

I have a flask project, and I am getting started learning the flask-admin module.

SqlAlchemy schema for the required tables.

import datetime
import sqlalchemy
from sqlalchemy.ext.declarative import declarative_base
from sqlalchemy.orm import backref, relationship

Base = declarative_base()


class Workgroup(Base):
    __tablename__ = 'workgroups'
    id = sqlalchemy.Column(sqlalchemy.Integer,

                           primary_key=True,
                           autoincrement=True
                           )
    name = sqlalchemy.Column(sqlalchemy.String(16))
    shorthand = sqlalchemy.Column(sqlalchemy.String(4))

    def __unicode__(self):
        return self.name

class Drive(Base):
    """
    A drive in an edit station.
    """
    __tablename__ = 'drives'

    id = sqlalchemy.Column(sqlalchemy.Integer,
                           primary_key=True,
                           autoincrement=True
                           )
    name = sqlalchemy.Column(sqlalchemy.String(64))
    computer_id = sqlalchemy.Column(sqlalchemy.Integer,
                                    sqlalchemy.ForeignKey(Computer.id)
                                    )
    computer = relationship('Computer', backref='drives')
    is_active = sqlalchemy.Column(sqlalchemy.Boolean)
    free_space = sqlalchemy.Column(sqlalchemy.BigInteger)
    used_space = sqlalchemy.Column(sqlalchemy.BigInteger)
    total_space = sqlalchemy.Column(sqlalchemy.BigInteger)
    percentage_full = sqlalchemy.Column(sqlalchemy.Float)
    boot_time = sqlalchemy.Column(sqlalchemy.DateTime)

    last_changed_workgroup = sqlalchemy.Column(sqlalchemy.DateTime)
    last_checked_in = sqlalchemy.Column(sqlalchemy.DateTime)
    last_notified = sqlalchemy.Column(sqlalchemy.DateTime)
    image_version = sqlalchemy.Column(sqlalchemy.String(64))
    image_date = sqlalchemy.Column(sqlalchemy.DateTime)
    current_workgroup_id = sqlalchemy.Column(sqlalchemy.Integer,
                                             sqlalchemy.ForeignKey(Workgroup.id)
                                             )
    workgroup = relationship('Workgroup', backref='drives')

Admin Test

class DriveAdmin(sqla.ModelView):
    column_display_pk = True
    column_hide_backrefs = False
    column_display_all_relations = True
    form_columns = [ 'computer_id', 'workgroup.name', ]
    column_list = ('computer.name', 'name', 'workgroup', 'computer.short_description', 'computer.notes',
                   'computer.station_type.description', 'computer.room.name')


class WorkgroupAdmin(sqla.ModelView):
    column_display_pk = True # optional, but I like to see the IDs in the list
    column_hide_backrefs = False
    column_list = ('id', 'name', 'shorthand')


# Create admin
admin = admin.Admin(app, name='Example: SQLAlchemy2', template_mode='bootstrap3')
admin.add_view(WorkgroupAdmin(schema.Workgroup, db))
admin.add_view(DriveAdmin(schema.Drive, db))

replacing form columns for 'workgroup' with 'workgroup.name' gives me an invalid model property name, even though I have successfully used schema.workgroup.name elsewhere in code.

The resulting admin form looks like this.

How do I go about getting the workgroup.name value to appear as opposed to the object representation?

Thanks for reading!

Answer 1

You need to get the workgroup class to return its name via the repr function. That way it will show in the field.

class Workgroup(Base):
    __tablename__ = 'workgroups'
    id = sqlalchemy.Column(sqlalchemy.Integer,

                           primary_key=True,
                           autoincrement=True
                           )
    name = sqlalchemy.Column(sqlalchemy.String(16))
    shorthand = sqlalchemy.Column(sqlalchemy.String(4))

    def __unicode__(self):
        return self.name

    def __repr__(self):
        return '<Workgroup %r>' % (self.name)