Re: Primary Key...Is One Required?

Bonnie, On Wed, 2 Jun 1999, Bonnie Annelin wrote: > I have a question regarding primary keys for tables. Is it necessary to > have a primary key for a table? No. > According to Informix Documentation, > if a primary key does not exist for a table, a primary key is composed > of all columns taken together. Does this mean that Informix > automatically generates a primary key? No. > I do a database dump (dbschema) > and do not see a primary key listed for my table. Also, I recently > attended an Informix Class where the instructor said that Informix does > not automatically generate a primary key. I'm now wondering whether > or not I should create a serial record_num primary key for this table > because if one is automatically generated out of every column (I have a > large number of columns) and because primary keys are automatically > indexed, this will be a very large/inefficient index. > > Thanks, > Bonnie Annelin > Informix does not require primary keys. You may set these up if you require them also informix does not automatically generate primary keys. Columns that make up a primary key can not be NULL. My suggestion is leave the table(s) as they are. Create indexes if and when required. Stephen C Manga Email: Stephen.Manga@dbgroup.co.nz Stephen@quanta.co.nz