Which is better (more columns or rows) ?

At 9:16 AM +0800 4/10/01, thomas wong wrote:

Hi,
I have recently tried some simple test on the postgresql 7.0
running on a PIII 600MHz, 128 Mbytes RAM . I created a simple Visual
Basic app that query two tables.
The first one consist of 10 columns and the other 30 columns. I
inserted about 250,000 records into each tables and then do a
"vacuum" on the database.
Next I query to select about 100,000 records. I repeated this query
for 5 times and each time I will do a "vacuum".
Below is the average timing I get:-
For 10 columns table ~109s
For 30 columns table ~ 112s

Is it true that I can design database tables to have more columns
without performance degradation during query ?

If your data is such that you can just put everything in one table
with lots of columns, you're better off with a flatfile database.

The whole point of relational databases is the flexibility you get
from having normalized data, which in general means more tables with
fewer columns in each.