[Corrected top-posting]
>> To: python-list@python.org
From: fr...@chagford.com
Subject: Question about ast.literal_eval
Date: Mon, 20 May 2013 09:05:48 +0200
Hi all
I am trying to emulate a SQL check constraint in Python. Quoting from
the PostgreSQL docs, "A check constraint is the most generic constraint
type. It allows you to specify that the value in a certain column must
satisfy a Boolean (truth-value) expression."
The problem is that I want to store the constraint as a string, and I
was hoping to use ast.literal_eval to evaluate it, but it does not work.
On 20/05/2013 09:34, Carlos Nepomuceno wrote:
It seems to me you can't use ast.literal_eval()[1] to evaluate that kind of
expression
> because it's just for literals[2].
Why don't you use eval()?
Because users can create their own columns, with their own constraints.
Therefore the string is user-modifiable, so it cannot be trusted.
Frank
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