why this sql query doesn't work in python?

Question

I've a function findParent that takes a string, compares it with something else in db and returns another string. I wrote this in a .py file.

products=db(findParent(db.product_info.source_place)==auth.user.place).select()

The problem is, db.product_info.source_place doesn't etract source_place from db but instead sends the string itself ie findParent recieves db.product_info.source_place but not the corresponding value from the db .

What am I doing wrong?

Answer 1

When you are comparing two fields in case like:

products=db(table1.field1==table2.field2).select()

It return a table after applying the join on these two fields. When you use findParent(db.product_info.source_place) , the findParent is just considering as string db.product_info.source_place because it is not actually called for all the rows in the tables and called once and evaluated and then all rows of the auth.user are compared with that return value for the place column.

Solution added:

rows=db(db.product_info).select(db.product_info.source_place) listwantedsource=[] for row in rows: listwantedsource.append(findParent(row.source_place)) products=db(auth.user.place.belongs(listwantedsource)).select()