Neil Conway wrote: > I'd like to add a new column to pg_attribute that specifies the > attribute's "logical position" within its relation. The idea here is > to separate the logical order of the columns in a relation from the > on-disk storage of the relation's tuples. This allows us to easily & > quickly change column order, add an additional column before or after > an existing column, etc. > > At present, attnum basically does three things: identifies an column > within a relation, indicates which columns are system columns, and > defines the order of a relation's columns. I'd like to move this last > functionality into a separate pg_attribute column named "attpos" (or > "attlogicalpos"): > > - when the table is created, attnum == attpos. System columns > have attpos < 0, as with attnum. At no point will two > columns of the same relation have the same attpos. > > - when returning output to the client and no column ordering > is implied by the query (e.g. "SELECT * ..."), we sort the > columns in ascending attpos order.
Seems the only cases where attpos would be used would be SELECT *, INSERT with no column list, and COPY --- seems like a nifty feature. -- Bruce Momjian | http://candle.pha.pa.us [EMAIL PROTECTED] | (610) 359-1001 + If your life is a hard drive, | 13 Roberts Road + Christ can be your backup. | Newtown Square, Pennsylvania 19073 ---------------------------(end of broadcast)--------------------------- TIP 4: Don't 'kill -9' the postmaster
