Barker's notation

The Martin notation ( also Krähenfußnotation; engl crow's foot notation. ) By James Martin, Bachmann and Odell is a notation for semantic data modeling to represent simplified entity-relationship models.

It uses a 1: n relationship so-called crow's feet and is therefore also called Krähenfußnotation.

The rectangles designate the entity, which are interconnected by means of connection lines. ( In the diagram stands such as " person " in relation to "place" ).

The cardinalities ( multiplicities ) are 0 ( zero), | in (one) or the crow's foot (any number ). For each relationship are stacked two cardinalities that describe the minimum and the maximum occurrence.

The graphs in the graph read as follows:

• A person is born into a minimal, maximum one place.
• One person has died in minimal zero, maximum one place.
• A person makes a vacation in minimal zero, a maximum of many places.
• One person was already in a minimal, maximal many places.
• In the opposite direction, no statement about the cardinality is made.

The cardinalities shown in parentheses ( eg 0 n. ) In the diagram denote the analog UML notation and do not belong to Martin notation.

• Database Modeling