Question

I need a temporary table in my programme. I have seen that this can be achieved with the “mapper” syntax in this way:

t = Table(
    't', metadata,
    Column('id', Integer, primary_key=True),
    # ...
    prefixes=['TEMPORARY'],
)

Seen here

But, my whole code is using the declarative base, it is what I understand, and I would like to stick to it. There is the possibility of using a hybrid approach but if possible I’d avoid it.

This is a simplified version of how my declarative class looks like:

import SQLAlchemy as alc
class Tempo(Base):
    """
    Class for temporary table used to process data coming from xlsx
    @param Base Declarative Base
    """

    # TODO: make it completely temporary

    __tablename__ = 'tempo'

    drw = alc.Column(alc.String)
    date = alc.Column(alc.Date)
    check_number = alc.Column(alc.Integer)

Thanks in advance!

EDITED WITH THE NEW PROBLEMS:

Now the class looks like this:

import SQLAlchemy as alc

class Tempo(Base):
        """
        Class for temporary table used to process data coming from xlsx
        @param Base Declarative Base
        """

        # TODO: make it completely temporary

        __tablename__ = 'tempo'
        __table_args__ = {'prefixes': ['TEMPORARY']}

        drw = alc.Column(alc.String)
        date = alc.Column(alc.Date)
        check_number = alc.Column(alc.Integer)

And when I try to insert data in this table, I get the following error message:

sqlalchemy.exc.OperationalError: (OperationalError) no such table:
tempo u'INSERT INTO tempo (...) VALUES (?, ?, ?, ?, ?, ?, ?, ?)' (....)

It seems the table doesn’t exist just by declaring it. I have seen something like create_all() that might be the solution for this (it’s funny to see how new ideas come while explaining thoroughly)

Then again, thank you very much!

Answer 1

Is it possible to use __table_args__? See https://docs.sqlalchemy.org/en/14/orm/declarative_tables.html#orm-declarative-table-configuration

class Tempo(Base):
    """
    Class for temporary table used to process data coming from xlsx
    @param Base Declarative Base
    """

    # TODO: make it completely temporary

    __tablename__ = 'tempo'
    __table_args__ = {'prefixes': ['TEMPORARY']}

    drw = alc.Column(alc.String)
    date = alc.Column(alc.Date)
    check_number = alc.Column(alc.Integer)