The data model defines the relationships between data

types:

• 1:1
• 1:many
• many:many

Example:

1. In the hierarchical model, have strict inheritance: department - employees and department- projects
2. network model does many:many add employees -projects
3. relational deatabase has no links, but rather relationships in the data, a dereference means making a new query. This means new fields don't have to be made when things change. Easy, and flexible, but no relationship checking.

source psfile jl@crush.caltech.edu index