Walking through a mysql db

[Jeff Elkins]

I'm writing a small wxpython app to display and update a dataset. So far, I
get the first record for display:

try:
cursor = conn.cursor ()
cursor.execute ("SELECT * FROM dataset")
item = cursor.fetchone ()

Now, how do I step through the dataset one row at a time? My form has 'next'
and 'back' buttons, and I'd like them to step forward or back, fetching the
appropriate row in the table. I've tried setting cursor.rownumber by
incrementing it prior to the fetchone() w/o effect.

Thanks for any pointers.

Jeff Elkins

 

[Benjamin Niemann]

I'm writing a small wxpython app to display and update a dataset. So far,
I get the first record for display:

try:
cursor = conn.cursor ()
cursor.execute ("SELECT * FROM dataset")
item = cursor.fetchone ()

Now, how do I step through the dataset one row at a time? My form has
'next' and 'back' buttons, and I'd like them to step forward or back,
fetching the appropriate row in the table. I've tried setting
cursor.rownumber by incrementing it prior to the fetchone() w/o effect.

You could either execute N-1 fetchone()s before you fetch the Nth dataset
(with N starting at 1)
or use the 'LIMIT' feature of MySQL:
cursor.execute ("SELECT * FROM dataset LIMIT %s,1", n)
where n is the index of the requested dataset (starting at 0)

 

[wes weston]

I'm writing a small wxpython app to display and update a dataset. So far, I
get the first record for display:

try:
cursor = conn.cursor ()
cursor.execute ("SELECT * FROM dataset")
item = cursor.fetchone ()

Now, how do I step through the dataset one row at a time? My form has 'next'
and 'back' buttons, and I'd like them to step forward or back, fetching the
appropriate row in the table. I've tried setting cursor.rownumber by
incrementing it prior to the fetchone() w/o effect.

Thanks for any pointers.

Jeff Elkins

Jeff,
You just check for a fetchone return of None. "list" is a list
of tuples here.
...
cursor.execute( sql )
list = []
while 1:
row = cursor.fetchone()
if not row:
break
list.append(row)
...
wes