On 21/07/17 20:36, Jonathan Rogers wrote:
> On 07/21/2017 12:24 PM, Graeme Gemmill wrote:
>> I wish to issue an UPDATE command to update 4 columns of a row that has
>> a unique primary key vindex:
>>
>> SQL = "UPDATE contact SET firstname, addnlnames, surname, rev WHERE
>> vindex =? (%s, %s, %s, %s);"
>> data = (.......)
>> cursor.execute(SQL, data)
>>
>> How is the value of vindex specified? Is my ? to be replaced by %s where
>> the value of vindex is the first of the data values?
> It seems you may be confused about both SQL syntax and psycopg2's
> handling of parameters. Start with the Posgtgres documentation about the
> UPDATE statement:
>
> https://www.postgresql.org/docs/9.6/static/sql-update.html
>
> As explained in its documentation, "%s" is the psycopg2 placeholder. The
> SQL string you should pass to pyscopg2 is "UPDATE contact SET firstname
> = %s, addnlnames = %s, surname = %s, rev =% WHERE vindex = %s".
>
> http://initd.org/psycopg/docs/usage.html#passing-parameters-to-sql-queries
>
Thank you John Evan, Jonathan for replies. The structure I used is valid
and even recommended for an INSERT command; I couldn't see how to use it
for an UPDATE. Anyway, sorted now.
Graeme