python - psycopg2 set PRIMARY KEY from tuple with placeholder -

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how can set primary key in psycopg2 tuple of values being looped in tuple?

for example have tuple

meetattrs = ('id', 'venue', 'date', 'rail', 'weather', 'trackcondition')

and want create table , extract , insert values. meetattrs wish set id primary key.

conn = psycopg2.connect("") conn, conn.cursor() cur:         # first, create tables.     cur.execute("drop table if exists meetings, races, horses")     cur.execute("create table meetings (id integer primary key, " +                 ", ".join("%s varchar" % fld fld in meetattrs)                 + ")")

this creates error, unsure how resolve.

traceback (most recent call last):   file "racemeeting.py", line 56, in <module>     + ")") psycopg2.programmingerror: column "id" specified more once

your current sql query after join performed , placeholders take values is:

'create table meetings (id integer primary key, id varchar, venue varchar, date varchar, rail varchar, weather varchar, trackcondition varchar)'

id specified twice.

you can build query in cleaner way:

query_params = " %s integer primary key" + ", %s varchar" * (len(meetattrs) - 1)

and sql statement becomes: 

"create table meetings (" + query_params % meetattrs + ")"

after insertion of placeholder values:

'create table meetings (id integer primary key, venue varchar, date varchar, rail varchar, weather varchar, trackcondition varchar)'

be sure tuple has first item id


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