On 19/05/11 13:53, Andre Engels wrote:
On Thu, May 19, 2011 at 6:36 AM, Joe Aquilina<j...@chem.com.au> wrote:
I am new to this list and very much a beginner to Python. Please excuse me
if this is a silly question, but in all my searches this morning I have not
been able to find an answer.
I have a (single table) database file (SQLite3). It has one table, call it
literature, with an integer, autoincrement primary key field. I have created
a data entry form in Python that I want to use to enter new rows into this
database file. On the data entry form I will enter the values for a new
table row - all except the primary key field.
What I want to be able to do is to have my data entry form autoincrement
this primary key field for me, with no ability to change the contents on the
data entry form, and save this incremented value as the value of the num
field when I save the new row.
So for example, if the last row in the table has a value of 256 in the num
field, I want the value of 257 to be saved as the value of the num field
into the new row I am adding, without having to see or or enter this new
value (or indeed the previous value) on the data entry screen.
I hope this makes sense. But how do I do this?
I thought about doing a
SELECT num FROM literature;
from the table, then getting the contents of the num field of the last row
in the data that a fetchall() retrieves and incrementing it to save with the
new row.
However, the fetchall() returns the data as tuples, not integers and I don't
know how to convert from a tuple data type to an integer to make this work.
Is this possible? Or can I achieve my objective in some other way?
Any advice/assistance would be appreciated. Thanks in advance.
l assume the tuple is a 1-tuple?
Anyway, let fetch be the name of your tuple, then
fetch[0]
will be the first element of the tuple,
fetch[1]
the second element, and so on.
Hello Andre.
I realised after I read your response that I probably hadn't included
enough information, partly due to my inexperience in Python and partly
due to haste on my part.
AFter my original post, I had a little play in Python and was able to
create this tuple:
[1, 2, 3, 4, 5]
from which I was able to extract any item I wanted as an integer and
work with as I wanted. I am guessing that this is a 1-tuple.
It is when I do the fetchall() from the table, that I get the following:
[(1,), (2,), (3,)]
I don't know enough to know whether this is a 1-tuple or not. It is from
this tuple that I want to extract the 3 as an integer so that I can
increment it and save as an integer into the next row in the table.
Hope that is a little clearer.
Cheers.
Joe Aquilina
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