A Comparison of Three Systems Modeling Methodologies - High-Performance Web Databases: Design, Development, and Deployment - page 208

Exhibit 13-8. Summary of differences among the E-R, information

model, and OMT systems modeling techniques.

Topic E-R Information Model OMT

Entity Entity Object Object

Operations No No Yes

Primary Key Yes Yes No

Foreign Key No Yes No

Participation Constraint Yes Yes Yes

Participation Look Here

1

Look Across

2

LA

Notation (LH) (LA)

Ternary Relationships Yes Yes Yes

Cardinality Notation LA LA LA

Multiplicity to Association Object No Yes No

Attributes on Relationships Yes Yes Yes

Relationship Qualifiers:
Role Yes Yes Yes

Ordering No No Yes

Qualifier No No Yes

Attribute Data Type No No Yes

Default Value No No Yes

Generalization Hierarchy Yes Yes Yes

Aggregation Yes (limited) No Yes

Notes

1. Look here (LH) notation is next to the primary entity in a relationship.
2. Look across (LA) notation is next to the secondary entity in a relationship.