Re: Reversal of Records
Jeffrey F. Lawhorn writes: > > > [ text deleted ] > > The reason for this is the reason that SERIAL exists - it provides > > an automatically generated primary key. The only implied > > requirements are that a type SERIAL be UNIQUE and NOT NULL. > > In addition, a quick review of several Informix 4.0 manuals > > indicates that there is no promise made there about ordering > > of type SERIAL with respect to INSERT sequence. > > [ text deleted ] > > Greg, please tell us which pages of the 4GL manuals discuss "ordering of type > SERIAL with respect to INSERT sequence." I can't find anything. > > > > >Sorry if I wasn't clear here - what I am saying is that I can't find > >anything either. If Informix doesn't make the promise, they won't feel > >obligated to keep it (exactly as in the case of ROWID). > > The Informix SQL Version 4.00 User Guide (page 2-20) states: > > Serial numbers ensure that a sequential number is assigned to > each row of the table. You do not need to enter data in a SERIAL > column. Eash time you add a new row to a table, INFORMIX-SQL > automatically assigns the next number, in sequence, to the SERIAL > column. Normally, the starting number is one, but you can select any > number greater than zero as your starting number. The highest serial > number INFORMIX-SQL can assign is 2,147,483,647. > > So I would say that Informix has made a promise about the order of the > values in a SERIAL column. Making a clustered index on a serial column > will keep the data in the table in the order it was entered. However, SQL > (and perform) make no guarentees of the order the data will be returned > unless you put an order by on the select. I do not know of any way to do > this in perform. > > jeffl Jeffrey - You're absolutely right. ------------ DHL WORLDWIDE EXPRESS ------------------------------------------- Greg Bryan gbryan@ssf-sys.dhl.com DHL Systems Data Administrator uunet!ssf-sys.dhl.com!gbryan San Francisco -------------------------------------------------------------------------------