I'm trying to write to a file but it's not working. I've gone through step-by-step with the debugger (it goes to the write command but when I open the file it's empty).

My question is either: "How do I see what the error is so I can debug?", "What can go wrong when trying to write to a file that would cause it to behave this way?".

sqlScript = open('script-file.sql', 'a')

    try:
         sqlScript.write(sqlLine)
    except IOError as (errno, strerror):
         print "I/O error({0}): {1}".format(errno, strerror)

This should be simple but I can't seem to find an answer. Also, I apologize in advance as English is a second language.

Edit: I put a print statement just before and the string is not empty.
Edit2: I'm using python 2.6 if that factors in somehow.

Edit 3: I've found a "solution" to my error. I decided to try and run my script using IDLE instead of PyCharm and it works like a charm (pun intended). I have no clue why, but there it is. Any reason why that would happen?!

• python
• file-io

Building on Chris Morris' answer, maybe do something like this:

try:
    sqlScript.write(sqlLine)
except Exception as e:
    print type(e)
    print str(e)

This will catch any Exception thrown (provided it's a subclass of Exception, of course) and tell you the type and the error message.

Also, it's possible to define multiple except: cases for different possible exceptions, so maybe try doing that for each exception that might be potentially thrown/raised.

The following code allows you to see what exception it is that is being thrown, and see a trace of where it originated from.

try:
    sqlScript.write(sqlLine)
except:
    print "Unexpected error:", sys.exc_info()[0]
    raise

See http://docs.python.org/tutorial/errors.html for more info.

You have to put your cursor at the beginning of the file. You can do that with seek method:

myScript.seek(0)

See this answer: https://stackoverflow.com/a/2949648/2119117

If no exception is being tossed, I'd suspect the string variable 'sqlLine' is empty.

Did you print it before the write statement?

Are the keywords in the script in lowercase? The same thing happened to me in another db and I solved it by changing words to UPPERCASE.

Your current working directory isn't what you expect it to be and it's successfully writing to some script-file.sql in another directory. Try printing os.getcwd() and make sure it's what you expect, and look in that directory.

It happened on my linux environment but work on windows try

sqlScript = open('script-file.sql', 'a', buffering=False)

or

sqlScript = open('script-file.sql', 'a', 0)