Help: python-postgres-informix interaction problems

[J Dubal]

Hello good people!

We have developed Informix RDBMS based commercial applications in
Informix-4gl. It is a good procedural language with embeded SQL. We
are trying to rewrite some apps in Python with postgresql backend for
licensing reasons. Python is good too. We are trying to do this with
latest versions of RH linux (7.2), python 2.1 and postgres 7.1.3. We
face following issues:

1. We have to read data from informix db, process it and insert into
postgres. We are using informixdb module (DBAPI 1) which is bit dated.
In Informix we 'select custno, custname, custaddr1, ... into progvar1,
progvar2, ... from custmf where ...' In python, we say fetchone() and
we get a list. We are then moving the elements of the list to named
program variables thus:
        pcustno = list1[0]
        pcustname = list1[1]
        pcustaddr1 = list1[2]
        ... as many as reqd
This way we give meaningful names to data items read from db and
process further.
Is there a better, more elegant/efficient way to to this?

2. To insert this data into postgres, we used to use pygres included
in the postgres distribution (latest). We had to stop using this
because we couldn't find a way to find out how many rows it have
inserted, updated or deleted after such statements are executed ie we
couldn't find a way to check the status or return code. So we switched
over to PoPy which is DBAPI2 and where we could check number of rows
affected. Is this right thing to do?

3. In order to insert data into postgres, we have to compose an insert
statement thus:
        cur.execute("insert into custmf (custno, custname,
custaddr1,...)
            values (%i,'%s','%s'...)" %(pcustno,pcustname,
pcustaddr1....))
Is there a better way of doing this?

4. The above string substitute converts program variables holding null
value into 'None' which goes into target table as string 'None'. To
avoid this we parse all columns to check if they are 'None' and
replace them by ''. Is there a better way to do this?

5. The above check works only on string variables. We have not found
yet a way to handle nulls in numeric columns. Please suggest a
solution.

6. If the character columns happen to contain quotes, the above
composed insert statement breaks. Please suggest a solution.

Any help is greatly appreciated.
Thanks in advance.
Dubal