On Sep 29, 2005, at 4:38 , Daryl Richter wrote:
Ferindo Middleton Jr wrote:
Is there a way to change the position attribute of a column in a
table? I have data that I need to import into various tables in my
db on a consistent basis... I usually us e the COPY ... FROM query
but I can't control the -order- of the fields my client dumps the
data so I would like to be able to change the position the columns
in my table to be able to better align the data to be imported
with the format of my table. I was thinking I could do something
like "ALTER TABLE ALTER COLUMN ... " or something like that to
change the columns position in the table but I can't figure out how.
Ferindo
---------------------------(end of
broadcast)---------------------------
TIP 6: explain analyze is your friend
Constantly changing the column order of a table doesn't make sense
(and is a pain!).
I would suggest setting up a temporary staging table with generic
column names to take in the input data and then using SQL to move
it into its permanent location.
Or specify the columns directly in the copy statement. Instead of
copy foo from <file>, do copy foo (bar,baz,bat) from <file>. Then you
only have to change the copy statement.
While SQL does allow columns to be referenced by column order, it's
far, far better to consider the columns of a table to be unordered
and (nearly) always specify your columns explicitly. It gives you
much more flexibility. Changing a few SQL statements to return (or
insert) the columns how you want them is much easier than changing
the underlying table structure and having to make sure *all* of your
queries then fit the new table structure.
Michael Glaesemann
grzm myrealbox com
---------------------------(end of broadcast)---------------------------
TIP 2: Don't 'kill -9' the postmaster
