[SOLVED] psycopg2 TypeError: not all arguments converted during string formatting

psycopg2 TypeError: not all arguments converted during string formatting

I'm trying execute a simple query, but getting this error no matter how I pass the parameters.

Here is the query (I'm using Trac db object to connect to a DB):

cursor.execute("""SELECT name FROM "%s".customer WHERE firm_id='%s'""" % (schema, each['id']))

schema and each['id'] both are simple strings

print("""SELECT name FROM "%s".customer WHERE firm_id='%s'""" % (schema, each['id']))

Result: SELECT name FROM "Planing".customer WHERE firm_id='135'

There is on error is a remove quote after firm_id=, but that way parameter is treated a an integer and ::text leads to the very same error.

Solution

It is recommended to not use string interpolation for passing variables in database queries, but using string interpolation to set the table name is fine as long as it's not an external input or you restrict the allowed value. Try:

cursor.execute("""
    SELECT name FROM %s.customer WHERE firm_id=%%s
    """ % schema, (each['id'],))

Rules for DB API usage provides guidance for programming against the database.