Logical Data Modeling

2 entities can be related as :

One to One : (1 : 1)

The interpretation of this is that an occurrence of an entity ‘A’ can relate to ONE and ONLY ONE occurrence of entity ‘B’, and an occurrence of entity ‘B’ can relate to ONE and ONLY ONE occurrence of entity ‘A’

One to Many : (1: N)

The interpretation is that ONE occurrence of entity ‘A’ can relate to ONE or MORE occurrences of entity ‘B’, but an occurrence of entity ‘B’ can relate to ONE ONLY occurrence of entity ‘A’

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