On Fri, 2003-08-01 at 12:44, Josh Berkus wrote: > Francisco, > > > Yes all fields belong to the same entity. I used 100 as an example it may > > be something like 60 to 80 fields (there are two tables in question). I > > don't formally do 3rd normal form, but for the most part I do most of > > the general concepts of normalization. > > > > > If not, then good design says to split the table. > > Actually, no, it doesn't. If all 60-80 fields are unitary and required > characteristics of the row-entity, normalization says keep them in one table.
You snipped out too much, because that's exactly what I said... Another way of writing it: only split the table if some of the fields are not unitary to the entity. > The only time NF would recommend splitting the table is for fields which are > frequenly NULL for reasons other than missing data entry. For those, you'd > create a child table. Although while this is good 4NF, it's impractical in > PostgreSQL, where queries with several LEFT OUTER JOINs tend to be very slow > indeed. Good to know. > My attitude toward these normalization vs. performance issues is consistenly > the same: First, verify that you have a problem. That is, build the > database with everything in one table (or with child tables for Nullable > fields, as above) and try to run your application. If performance is > appalling, *then* take denormalization steps to improve it. The OP was not talking about denormalizing ... It was: will vertically partitioning a table increase performance. And the answer is "sometimes", -- +-----------------------------------------------------------------+ | Ron Johnson, Jr. Home: [EMAIL PROTECTED] | | Jefferson, LA USA | | | | "I'm not a vegetarian because I love animals, I'm a vegetarian | | because I hate vegetables!" | | unknown | +-----------------------------------------------------------------+ ---------------------------(end of broadcast)--------------------------- TIP 2: you can get off all lists at once with the unregister command (send "unregister YourEmailAddressHere" to [EMAIL PROTECTED])