Solved

PL/Python NameError: global name '<variable>' is not defined

Posted on 2013-12-17
7
1,651 Views
Last Modified: 2013-12-23
I'm trying to create a PL/Python function for PostgreSQL.  Here's a simplified version that gets the error.
create or replace function eztest( ASIN varchar(10)) returns  integer AS
$$
plan = plpy.prepare("Select bookid from book where ASIN = $1", ["text"])
rv = plpy.execute(plan, [ ASIN ])
return rv["bookid"]
$$ language plpython2u;

Select eztest('B00DMYO2D2');

Open in new window


When I call the function with the SELECT statement, it complains
ERROR:  NameError: global name 'ASIN' is not defined
CONTEXT:  Traceback (most recent call last):
  PL/Python function "eztest", line 3, in <module>
    rv = plpy.execute(plan, [ ASIN ])
PL/Python function "eztest"

Open in new window


If I hardcode a value in, rather than using my variable, it works.  What am I doing wrong?

Thanks!
0
Comment
Question by:Daniel Wilson
[X]
Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people just like you are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
  • 4
  • 2
7 Comments
 
LVL 29

Assisted Solution

by:pepr
pepr earned 250 total points
ID: 39725995
I do not know plpy, and I cannot check it. Anyway, it seems you have to quote the ASIN  in the call. It should be a string literal, not a variable. Something like
rv = plpy.execute(plan, [ "ASIN" ])

Open in new window

0
 
LVL 9

Assisted Solution

by:techtonik
techtonik earned 250 total points
ID: 39727640
I can't find any reference that types like VARCHAR(10) are allowed in Python/PL.

Try to replace function parameter with eztest(ASIN text)
0
 
LVL 32

Accepted Solution

by:
Daniel Wilson earned 0 total points
ID: 39727897
Changing to text gets the same result.

However, changing the parameter name to lowercase resolved the issue.  Must have been a requirement I overlooked that parameters be lowercase.

create or replace function eztest( asin varchar(10)) returns  integer AS
$$
plan = plpy.prepare("Select bookid from book where ASIN = $1", ["text"])
rv = plpy.execute(plan, [ asin ])
return rv[0]["bookid"]
$$ language plpython2u;

Select eztest('B00DMYO2D2');

Open in new window

0
NFR key for Veeam Backup for Microsoft Office 365

Veeam is happy to provide a free NFR license (for 1 year, up to 10 users). This license allows for the non‑production use of Veeam Backup for Microsoft Office 365 in your home lab without any feature limitations.

 
LVL 9

Expert Comment

by:techtonik
ID: 39729026
Cool. Is this requirement specified somewhere?
0
 
LVL 32

Author Comment

by:Daniel Wilson
ID: 39729066
I haven't found a spec that says this.  So my results should be considered anecdotal and applying to my particular Ubuntu 12.04 LTS installation running PostgreSQL 9.3 and running under VMWare Player.  But ... perhaps ... the same solution will work in other contexts.
0
 
LVL 32

Author Comment

by:Daniel Wilson
ID: 39729075
As for mapping Postgres data types to Python, that is specified:
http://www.postgresql.org/docs/9.3/static/plpython-data.html#AEN60813

Any of the character types maps to a Python str.
0
 
LVL 32

Author Closing Comment

by:Daniel Wilson
ID: 39735718
Thanks for the ideas!
0

Featured Post

NFR key for Veeam Backup for Microsoft Office 365

Veeam is happy to provide a free NFR license (for 1 year, up to 10 users). This license allows for the non‑production use of Veeam Backup for Microsoft Office 365 in your home lab without any feature limitations.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Suggested Solutions

Title # Comments Views Activity
Trying to run a Python File 11 78
postgreSQL (pgAdmin 4 V1.1) script not finishing 2 73
Is it safe to dump postgresql database that is in production? 3 62
Postdresql 1 22
Dictionaries contain key:value pairs. Which means a collection of tuples with an attribute name and an assigned value to it. The semicolon present in between each key and values and attribute with values are delimited with a comma.  In python we can…
When we want to run, execute or repeat a statement multiple times, a loop is necessary. This article covers the two types of loops in Python: the while loop and the for loop.
Learn the basics of strings in Python: declaration, operations, indices, and slicing. Strings are declared with quotations; for example: s = "string": Strings are immutable.: Strings may be concatenated or multiplied using the addition and multiplic…
Learn the basics of if, else, and elif statements in Python 2.7. Use "if" statements to test a specified condition.: The structure of an if statement is as follows: (CODE) Use "else" statements to allow the execution of an alternative, if the …

756 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question