The relational database model

The databases you create with the Informix® database server are object-relational databases. In practical terms this means that all data is presented in the form of tables with rows and columns where the following simple corresponding relationships apply.

Relationship
Description
table = entity
A table represents all that the database knows about one subject or kind of thing.
column = attribute
A column represents one feature, characteristic, or fact that is true of the table subject.
row = instance
A row represents one individual instance of the table subject.

Some rules apply about how you choose entities and attributes, but they are important only when you are designing a new database. (For more information about database design, see the Informix® Database Design and Implementation Guide.) The data model in an existing database is already set. To use the database, you need to know only the names of the tables and columns and how they correspond to the real world.