[Tutor] Data conversion

[Andre Engels]

On Thu, May 19, 2011 at 6:36 AM, Joe Aquilina <joe at 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.


-- 
André Engels, andreengels at gmail.com