Storing a PostgreSQL ARRAY of ENUM values

Question

I have a table that can have a status:

statuses = [\'unmoderated\', \'nominee\', \'finalist\', \'winner\']
status = db.Enum(
    *statuses, name=\'enum_nomin         


        

Answer 1

I looked at Issue 3467 posted by Wichert Akkerman, and this work-around was posted. Credit to Mike Bayer. Declare the following class in your code (with the necessary imports, of course):

from sqlalchemy.dialects.postgresql import ARRAY
from sqlalchemy import cast

class ArrayOfEnum(ARRAY):
    def bind_expression(self, bindvalue):
        return cast(bindvalue, self)

    def result_processor(self, dialect, coltype):
        super_rp = super(ArrayOfEnum, self).result_processor(dialect, coltype)

        def handle_raw_string(value):
            if value==None:
                return []
            inner = re.match(r"^{(.*)}$", value).group(1)
            return inner.split(",")

        def process(value):
            return super_rp(handle_raw_string(value))
        return process

ArrayOfEnum is now a special column type that gets used in the model definition.

So instead of

class Judge(db.Model):
    statuses = db.Column(ARRAY(status))

Now you can do:

class Judge(db.Model):
    statuses = db.Column(ArrayOfEnum(status))

Now in your code you can assign values to statuses with a list and it will do the proper casting upon saving:

my_judge_object.status = ['unmoderated', 'nominee']