5. Examine the example

5. Examine the example

1. Properties of the relational data model

   • distinct relation name
     • Eg
   • one atomic (single) value
     • Eg
   • attribute : distinct name
     • eg
   • attribute values: same domain
     • eg
   • Order of attributes: no significance
     • eg
   • distinct tuples: No duplicate
     • eg
   • Order of tuples has no significance, theoretically
     • eg

2. entity integrity

   • no primary value can be null
     • eg
   • to identify individual tuples in a relation
     • eg
   • null values implies tuples cannot be identified
     • eg
   • entity integrity constraint is specified on individual relations
     • eg

3. referential integrity

   • refer to examples
   • specified between the two relations and is used to maintain consistency among tuples of the two relations
     • eg
   • a tuple in one relation that refers to another relation must refer to an existing tuple in that relation
     • eg