Creating a db.Sequence with sqalchemy

Question

I'm using postgres 10.5, python 3, flask and sqlalchemy. I'm trying to create a column in a users table with the following command

id = db.Column(db.Integer, db.Sequence('user_id_seq'), primary_key=True, autoincrement=True)

However, when I run this code and create a user, I get the error: error creating user (psycopg2.ProgrammingError) relation "user_id_seq" does not exist

How can I create the sequence 'user_id_seq' programmatically? Is there some way to check if it exists and create it if it does not using sqlalchemy

Marcos Stefani Rosa · Accepted Answer · 2018-10-25 23:47:50Z

1

In this case, you will need to create a code to run when starting the bank. for example:

def upgrade():
    op.execute("create sequence user_id_seq start with 1 increment by 1 nocache nocycle")

def downgrade():
    op.execute(sa.schema.DropSequence(sa.Sequence("user_id_seq")))

answered Oct 25, 2018 at 23:47

Marcos Stefani Rosa

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rmrf · Accepted Answer · 2018-10-25 23:57:00Z

0

Interestingly, this just ended up being a problem with the way my database table was previously defined. I dropped the table, ran the code and the sequence existed correctly.

answered Oct 25, 2018 at 23:57

rmrf

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