#ERDiagram
#ERDiagram #CardinalityConstarints Mapping Cardinality Constraints in ER | Mapping Cardinality in DBMS
A mapping constraint is a data constraint that expresses the number of entities to which another entity can be related via a relationship set.
It is most useful in describing the relationship sets that involve more than two entity sets.
For binary relationship set R on an entity set A and B, there are four possible mapping cardinalities. These are as follows:
One to one (1:1)
One to many (1:M)
Many to one (M:1)
Many to many (M:N)
Source: Database System Concepts | 6th Edition Book by Henry F Korth