On 04-Sep-2013, at 14:28, Alan Gauld <alan.ga...@btinternet.com> wrote:
> On 03/09/13 08:25, Ismar Sehic wrote:
>> help with postgres and csv:
>> i solved my problem by playing with the sql line a little.
>> it looked like this : sql = " UPDATE hotel SET path_picture =
>> "+"';"+hotel_url+"'
>> WHERE code LIKE '"+"%"+hotel_code+"'"
>> now it's like this : " UPDATE hotel SET path_picture = '" + hot_url +
>> "' WHERE code LIKE '%" + hot_code + "';"
>>
>> i guess the problem was in building the sql string, but i don't yet
>> quite understand what i did.can someone point me to some online resorces
>> about postgres and python integration?
>
> https://wiki.python.org/moin/PostgreSQL
>
While you're looking at all the information Alan pointed you to, consider one
other general bit of advice when programming with SQL queries. It is generally
a very convenient trick to use string formatting or string catenation to build
the bits of your query from pieces, like you did above ("UPDATE … SET
path_picture='" + hot_url + …).
Convenient, but a very, very bad idea in practice. This makes your program
vulnerable to SQL injection, which in many cases can have devastating effects
when someone exploits it. Assuming that the variables come from sources beyond
your control (and even if they are--at the moment--generated by you), use
parameterized queries (look for those in your API libraries). They usually
look something like the following (although specifics can vary), where you
leave a placeholder character like ? in the SQL string, and supply the data
values separately. Unlike using string-maniputation features of Python, the
database API knows exactly how to properly include those data values into the
SQL command for you:
some_api_function_to_do_sql("UPDATE hotel SET path_picture = ? WHERE code LIKE
?",
hot_url, '%' + hot_code + '%')
--steve
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