Comments on: Managing a simple database with Python, SQLite and wxPython, 7 (includes a question)

By: Paulo Nuin

Paulo Nuin — Wed, 22 Apr 2009 00:57:51 +0000

The suggestion worked really well, thanks a lot. I’m posting the new code after some testing.

By: Paulo Nuin

Paulo Nuin — Tue, 21 Apr 2009 17:23:10 +0000

Adomas, indeed it really looks ugly, and that’s the main reason for my question.

As Richard mentioned, SQLAlchemy would be overkill here. I really like SQLAlchemy, but here we have one database with one table.

Thanks everyone for the suggestions, I’m trying the placeholders now.

By: Richard Hall

Richard Hall — Tue, 21 Apr 2009 08:27:15 +0000

I agree with Mike – use named placeholders. The update statement is then easy to construct using something like

bind = {‘foo’:1, ‘bar’:2}
insert = ‘,’.join(['%s=:%s'%(y,y) for y in bind])
cu.execute(‘update mytable set %s where id=:id’%insert, bind)

this assumes your column names are equivalent to the keys in your dictionary. Alternatively, google for ‘object relational mappers’ (sqlalchemy is probably the best known mapepr for python) – this is exactly the sort of thing they do well, but might be overkill for your application.

By: Adomas

Adomas — Tue, 21 Apr 2009 07:21:31 +0000

The update statement looks really ugly here. Why not use SQLAlchemy or some kind of a mapper? For the start, you could generate the SQL on the fly yourself (i.e. “%s = ?” % name for all keys in the passed dict).

By: Mike

Mike — Mon, 20 Apr 2009 21:18:50 +0000

Try using named placeholders in the SQL statments

import sqlite3

con = sqlite3.connect(“:memory:”)
cur = con.cursor()
cur.execute(“create table people (name text, age real)”)

data = {“who”:”Yeltsin”, “age”:72}

# using (:who,:age) pulls values from the dictionary
cur.execute(“insert into people values (:who, :age)”, data)

cur.execute(“select * from people”)
print cur.fetchone()
#prints (u’Yeltsin’, 72.0)

data["age"] = 90.0
cur.execute(“UPDATE people SET age=:age WHERE name=:who”, data)

cur.execute(“select * from people”)
print cur.fetchone()
prints (u’Yeltsin’, 90.0)

con.close()