| Subject | Re: [ib-support] Primary Key |
|---|---|
| Author | Helen Borrie |
| Post date | 2003-06-06T11:34:41Z |
At 10:13 AM 6/06/2003 +0000, you wrote:
"relational". Unless the table has a primary key, or alternatively a
UNIQUE constraint, on a column or set of columns that uniquely identifies a
row, its usefulness in a relational database is limited. It can't be
referenced by a foreign key; its rows can't be uniquely found for a
searched update or delete or for a subquery; its reliability in joins is
unpredictable.
heLen
>HiNo influence on the DB. But keys are the glue that makes a database
>
>What influence does it have on a DB (using Firebird 1.0) when a table
>doesn't have a primary key ?
"relational". Unless the table has a primary key, or alternatively a
UNIQUE constraint, on a column or set of columns that uniquely identifies a
row, its usefulness in a relational database is limited. It can't be
referenced by a foreign key; its rows can't be uniquely found for a
searched update or delete or for a subquery; its reliability in joins is
unpredictable.
heLen