Why does adding my Sql UPDATE break my loop?

Question

I have the following code which, without the escaped SQL statement, is working fine - it iterates over the full set of returns from a previous SELECT query printing the ID, detected language (from bingtranslate) and text.

for row in c:
  lang=bingtranslate(row[0])
  tweetid = row[1]
  print tweetid, lang, row[0]
  #c.execute('UPDATE tweet SET iso_language_code=? WHERE id=?',(lang, tweetid))

When I unescape the UPDATE call, it loops once, and then stops.

What gives? No error reported. I'm sure it's something simple but I just can't crack it...

I'm not a python guy but does executing a query against your results collection c cause that collection to be reset? — Jeff Swensen
– Jeff Swensen, Commented Apr 28, 2011 at 21:22

Joril · Accepted Answer · 2011-04-28 21:22:52Z

4

I think the call to execute alters the state of c, so that on the next iteration the loop ends.

answered Apr 28, 2011 at 21:22

Joril

20.8k13 gold badges77 silver badges95 bronze badges

Sign up to request clarification or add additional context in comments.

2 Comments

Toby Over a year ago

ah, OK - so I should copy c into another list[] and then iterate over that? with nearly 1 million rows that's going to hurt, but at least it will work...

Marco Over a year ago

@Toby: I don't know Python, so I try to explain what I do in C#. You're executing a Command using same object of a DataReader, so you have a reset and so the strange behaviour. In my opinion you don't need to copy rows in another object, but only create a new Command object (empty) and use that to execute your query taking params from c. Correct me if I'm wrong, please.

Marco · Accepted Answer · 2011-04-28 21:35:01Z

1

I don't know Python, so I try to explain what I do in C#.
You're executing a Command using same object of a DataReader (c in python), so you have a reset and so the strange behaviour.
In my opinion you don't need to copy rows in another object, but only create a new Command object (empty) and use that to execute your query taking params from c.
Correct me if I'm wrong, please.

answered Apr 28, 2011 at 21:35

Marco

57.7k15 gold badges135 silver badges159 bronze badges

Collectives™ on Stack Overflow

Why does adding my Sql UPDATE break my loop?

2 Answers 2

2 Comments

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

2 Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Related