Return two SqlAlchemy Columns concatenated

Question

I am using Flask and SQLAlchemy. I have a Person model and I want an attribute which returns the Person's full name (first + last).

I tried using @declared_attr, but it outputs:

"person.first_name || :param_1 || person.last_name"

Here is my code:

class Person(Base):
    __tablename__ = 'person'

    id = Column(Integer, primary_key = True)
    type = Column(String(50))
    first_name = Column(String(120), index = True)
    last_name = Column(String(120), index = True)

    @declared_attr
    def name(cls):
        "Returns Person's full name."
        return cls.first_name + ' ' + cls.last_name

bsplosion · Accepted Answer · 2019-03-06 15:50:32Z

9

@davidism suggested using hybrid extension, whilst I say, why not use SQLAlchemy's column_property function?

Example:

class User(Base):
    __tablename__ = 'user'
    id = Column(Integer, primary_key=True)
    firstname = Column(String(50))
    lastname = Column(String(50))
    fullname = column_property(firstname + " " + lastname)

edited Mar 6, 2019 at 15:50

bsplosion

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answered Jun 18, 2015 at 11:18

Alex

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1 Comment

Chockomonkey Over a year ago

Yea this seems most applicable, they even use it as an example of how it's used in their docs! Cheers

davidism · Accepted Answer · 2014-04-16 14:34:11Z

6

Use the hybrid extension:

from sqlalchemy.ext.hybrid import hybrid_property

class Person(Base):
    # ...
    @hybrid_property
    def name(self):
        return '{0} {1}'.format(self.first_name, self.last_name)

    @name.setter
    def name(self, value):
        self.first_name, self.last_name = value.split(' ', 1)

    @name.expression
    def name(cls):
        return db.func.concat(cls.first_name, ' ', cls.last_name)

edited Apr 16, 2014 at 14:34

answered Apr 15, 2014 at 2:03

davidism

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