Perl to Python using MqSQLdb

[Mike P]

Hi All,

I've been given a Perl script that i'm trying to convert into python.
The aim of the script links to MqSQL database, but i'm stuck on one
part

my $sth = $dbh->prepare($sql)| |
die "Could not prepare SQL statement ... maybe invalid?:$!\n$s ql
\n";
$sth->execute()||
die "Could not execute SQL statement ... maybe invalid?:$!\n$s ql
\n";

while (my @row= $sth->fetchrow_array ()) {
my $combined = join(",", @row);
print "$combined\ n";
}

I don't know much MySQL or Perl..

Can anyone help to convert this for me?

Mike

[Daniel Mahoney]

Re: Perl to Python using MqSQLdb

On Tue, 12 Aug 2008 05:51:19 -0700, Mike P wrote:

Hi All,
>
I've been given a Perl script that i'm trying to convert into python.
The aim of the script links to MqSQL database, but i'm stuck on one
part
>
my $sth = $dbh->prepare($sql)| |
die "Could not prepare SQL statement ... maybe invalid?:$!\n$s ql
\n";
$sth->execute()||
die "Could not execute SQL statement ... maybe invalid?:$!\n$s ql
\n";
>
while (my @row= $sth->fetchrow_array ()) {
my $combined = join(",", @row);
print "$combined\ n";
}
>
I don't know much MySQL or Perl..
>
Can anyone help to convert this for me?
>
Mike

You could try something like:

cursor=db.curso r()
cursor.execute( sql)
while (1):
row = cursor.fetchone ()
if row == None:
break
combined = ', '.join(row)

This has NOT been tested.

More info available at http://www.kitebird.com/articles/pydbapi.html and
lots of other pages. Googling for "MySQLdb" should get you a decent list.

[Mike P]

Re: Perl to Python using MqSQLdb

Thanks for that Daniel,
I've been able to apply the logic to the rest of the script i'm
converting.

There are only two bits that i don't understand in the Perl script
that i need to convert,

my $sql = shift;

and

my @row = $sth->fetchrow_array ;
$$StartDate = $row[0];
$$EndDate = $row[1];
$sth->finish()

can you offer any advise?

Mike

[Jeroen Ruigrok van der Werven]

Re: Perl to Python using MqSQLdb

-On [20080812 15:16], Daniel Mahoney (dan@catfolks.n et) wrote:

>cursor=db.curs or()
>cursor.execute (sql)
>while (1):
> row = cursor.fetchone ()
> if row == None:
> break
> combined = ', '.join(row)

Why not something like:

for row in cursor.fetchall ():
combined = ', '.join(row)

--
Jeroen Ruigrok van der Werven <asmodai(-at-)in-nomine.org/ asmodai
イェルーン ラウフãƒãƒƒ ク ヴァン デル ウェルヴェ ン
http://www.in-nomine.org/ | http://www.rangaku.org/ | GPG: 2EAC625B
Focus on your one purpose...

[Mike P]

Re: Perl to Python using MqSQLdb

That is a nice piece of code,

I cracked the idea of the shift; problem, my final problem is still
how to convert

my @row = $sth->fetchrow_array ;
$$StartDate = $row[0];
$$EndDate = $row[1];
$sth->finish()

into python code as i'm not sure what $$ means

Any help on this final part would be great!

Mike

[Fredrik Lundh]

Re: Perl to Python using MqSQLdb

Jeroen Ruigrok van der Werven wrote:

>cursor=db.curs or()
>cursor.execute (sql)
>while (1):
> row = cursor.fetchone ()
> if row == None:
> break
> combined = ', '.join(row)

>
Why not something like:
>
for row in cursor.fetchall ():
combined = ', '.join(row)

which can be written as

combined = ', '.join(cursor.f etchall())

but probably won't work, since fetchall() returns a sequence of tuples,
unless I'm mistaken. Try something like this instead:

combined = ', '.join(row[0] for row in cursor.fetchall ())

</F>

[Fredrik Lundh]

Re: Perl to Python using MqSQLdb

Mike P wrote:

That is a nice piece of code,
>
I cracked the idea of the shift; problem, my final problem is still
how to convert
>
my @row = $sth->fetchrow_array ;
$$StartDate = $row[0];
$$EndDate = $row[1];
$sth->finish()
>
into python code as i'm not sure what $$ means

according to a quick google, fetchrow_array is equivalent to Python's
fetchone (read one row from the database into a sequence object), so the
above is simply:

row = cursor.fetchone ()
start_date = row[0]
end_date = row[1]

in Python. if you know for sure that the SQL statement only fetches two
columns, you can simply do

start_date, end_date = cursor.fetchone ()

</F>