Array Problem

mikesm

Hi everyone,
I am writing a python program using PyADO to add some data to an 'mdb'
database. For example,

filename = UserObjs.mdb
table I am working with = Lines
fields I am working with = ID and Metrics

The 'ID' field is just a number field. The 'Metrics' filed is an OLE object.
In this OLE object assigned in Microsoft Access, I need to include a series
of latitude/longitude numbers as in an array.

The problem I have is that, let's suppose I want to add this array:
[(23.00000,56.5897),(23.4569,58),(244569,60)]. I can add it with no problem to the OLE field, but...when I read the database (SELECT etc..), what I get is something like
this: [ *(*2*3*.*0*,...) ]

(Note: Here, I used the * to symbolize spaces.)

What I wanted was to store the array as a byte stream. How can I do that?

I'd appreciate any help I could get on this!

Thank you so much!!!

Regards,

Michel
PS: Below is the code I am using to insert / read the data:

****To insert:

Expand|Select|Wrap|Line Numbers

 
import PyADO

import win32com.client

import sys
 
id_number = raw_input("ID? ")
 
id_metrics = [(23.00000,56.5897),(23.4569,58),(244569,60)]
 
conn = win32com.client.Dispatch(r'ADODB.Connection')

DSN = 'PROVIDER=Microsoft.Jet.OLEDB.4.0;DATA

SOURCE=C:\msm_test\OLE_project\UserObjs.mdb;'

sql_statement = "INSERT INTO Lines (ID,Metrics) VALUES ('%s','%s');"

%(id_number,id_metrics)
 
conn.Open(DSN)

conn.Execute(sql_statement)

conn.Close()

*** To read the data

Expand|Select|Wrap|Line Numbers

 
import PyADO
 
conn =

PyADO.connect(None,user='admin',password='',host=None,database='C:\\msm_test\OLE_project\UserObjs.mdb',provider='Microsoft.Jet.OLEDB.4.0')
 
curs = conn.cursor()
 
curs.execute("select * from Lines")
 
result = curs.fetchall()

descr = curs.description

for row in result:

    for col in row:

        print col
 
curs.close()

conn.close()

bvdet

Try storing the data as str objects.

mikesm

I have tried that and I get the same thing.

How do I convert my array to byte stream?

bvdet

I know next to nothing about DB/Python interfaces, so I am mostly guessing. Why not try parsing the returned string? If you want to store the data as a byte stream, you may need a different field type in the DB.

Example data parse using eval():

Expand|Select|Wrap|Line Numbers

 >>> returned_data = "[ (2 3 . 0 0 0 0 0 , 5 6 . 5 8 9 7 ) , ( 2 3 . 4 5 6 9 , 5 8 ) , (2 4 4 5 6 9 , 6 0 ) ]"

>>> eval(returned_data.replace(" ", ""))

[(23.0, 56.589700000000001), (23.456900000000001, 58), (244569, 60)]

mikesm

Even by including your suggestion, that is, using eval and replace, it still adds spaces between the data. And because of the spaces, I can't access the data correctly in another program.
The same thing happens if I Pickle the data before adding to the database.

mikesm

There's another test you can make:
test = (2,3)
import cPickle
testpickle = cPickle.dumps(test,2)
testpickle
print testpickle

The last two commands are very different. When you type just testpickle, you get something like:
'\x80\x02K\x02K\x03\x86q\x01.'
when you type 'print testpickle', you get:
€ K K † q .
There are spaces between the elements. These are the spaces I am mentioning here. This is how the dataset is being stored in the mdb database. How do I get rid of these 'null bytes'?
Thanks!
Mike

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