Python script hangs on cursor.execute()

Question

I'm a newbie in Python

I'm debugging an existing script which is as follows,

print "Table name: %s " %table_name_r
print "Between: %s " % between
cursor = db.cursor()
print "Total Rows: %s " % cursor.rowcount
cursor.execute("""select contactid,li_url_clean,li_company,complink from """+ table_name_r +""" where li_company is not null and id_auto between """+between)
print "Execution complete"

I'm getting the below output,

Table name: li_records
Between: 4 and 6
Total Rows: -1

I have 2 questions here,

1.) (Resolved) My table li_records have 91 rows in it then why I'm getting the rowcount as -1?

2.) Why my script hangs up on cursor.execute?

Question 1 resolved: Like many of you pointed out the reason I'm getting '-1' is because I have not executed the query yet

Any help is appreciated. Thanks in advance.

• picmate 涅: You need to call cursor.rowcount after cursor.execute()
• picmate 涅: I believe db is a connection object, correct?
• picmate 涅: Ok, did you tested your query in the server? does it work there and give you the intended results?
• picmate 涅: If the query is unresponsive in the client, then it is not a problem in your python code. It is a possible problem in your sql query.
• picmate 涅: Could you try without the between clause? Maybe, that could be giving the error, try the integer inequalities for instance.

Answer 1

You haven't executed the query yet, so the database doesn't know the amount of rows that will be in the result. See also the docs on rowcount.

It states:

As required by the Python DB API Spec, the rowcount attribute "is -1 in case no executeXX() has been performed on the cursor [..]

As to why your execute method hangs, I don't know. Could you construct the query string outside of the method call like so:

query = "select contactid,li_url_clean,li_company,complink from " + table_name_r + " where li_company is not null and id_auto between " + between
cursor.execute(query)

If you do it like that, you can also print it before executing. That way you can check more easily to see if there's anything wrong with the query.

• Saumil: Thank you Jasper, I understood the problem with my first question. Like you suggested I'm printing out the query before executing it and it is just like I expected.
• Jasper: Mmm, and copying the printed query and executing it through sqlite directly gives you the expected results?
• Saumil: I'm not using sqlite but an alternative called 'Emma', none of my query runs on that application, not even a simple 'select * from tablename' because it crashes up. Do you think this could be the reason?
• Jasper: I don't know Emma, so I can't comment on any specifics about that. Are you using the built-in sqlite module in Python, in the hopes that Emma has a compatible enough API, or are you using a special Emma module? I found this on Github: github.com/myemma/EmmaPython
• Jasper: Haha, sorry. I just discover that what I linked is totally not what you're talking about. I can't find anything named 'Emma' that is even close to a database. Could you provide me with a link?