Thread: Field order
I've searched the archives and found this question was asked in 2001 but never answered. Does the order of fields in a table make a difference? In Paradox (from whence I come), there was some belief that reliability was increased if memo (text) fields were placed at the end of the table. If field order does make a difference, does the EMS PostgreSQL manager "reorder" function physically rearrange the fields?
Thanks for your time in considering this basic question
On Wed, Aug 17, 2005 at 12:09:12 -0600, Michael Schmidt <MichaelMSchmidt@msn.com> wrote: > I've searched the archives and found this question was asked in 2001 but never answered. Does the order of fields in atable make a difference? In Paradox (from whence I come), there was some belief that reliability was increased if memo(text) fields were placed at the end of the table. If field order does make a difference, does the EMS PostgreSQL manager"reorder" function physically rearrange the fields? > > Thanks for your time in considering this basic question Some space can be saved by putting the columns with the largest alignments first. The columns are not moved around to do the above, but are kept in the declared order.
On Wed, Aug 17, 2005 at 03:24:58PM -0500, Bruno Wolff III wrote: > On Wed, Aug 17, 2005 at 12:09:12 -0600, > Michael Schmidt <MichaelMSchmidt@msn.com> wrote: > > I've searched the archives and found this question was asked in 2001 but never answered. Does the order of fields ina table make a difference? In Paradox (from whence I come), there was some belief that reliability was increased if memo(text) fields were placed at the end of the table. If field order does make a difference, does the EMS PostgreSQL manager"reorder" function physically rearrange the fields? > > > > Thanks for your time in considering this basic question > > Some space can be saved by putting the columns with the largest alignments > first. > The columns are not moved around to do the above, but are kept in the > declared order. Ugh, and here I'd been doing it the other way around. I assume variable-length stuff should always go last, right? This make sense? Variable goes last, always Larger alignment before smaller NOT NULL before nullable -- Jim C. Nasby, Sr. Engineering Consultant jnasby@pervasive.com Pervasive Software http://pervasive.com 512-569-9461
Thanks for the comments and help! I'll set column order accordingly.
On Wed, Aug 17, 2005 at 17:40:34 -0500, "Jim C. Nasby" <jnasby@pervasive.com> wrote: > > Ugh, and here I'd been doing it the other way around. I assume > variable-length stuff should always go last, right? I think it depends on the alignment of the type. Certain text, char and varchar should go at the end. Nullable columns also make a difference since there is a shortcut used for rows that contain nulls.