Relational model
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The document discusses mapping entities to a relational database model. Entities are mapped as relations, with the entity name becoming the relation name and attributes becoming relation attributes. The primary key of a relation maps to the primary key of the entity. One-to-many relationships insert the primary key of the "one" entity into the "many" entity. One-to-one relationships insert the primary key into the entity with a minimum cardinality of zero. Many-to-many relationships create a new relationship table containing the primary keys of both entities.
Relational model
- 1. Muhammad Umair Oracle Database 11g Developer Track
- 2. Relational Model A set of database relations in which each relation has a distinct name Mapping Entities into Relational Model Entity is mapped as a relation Name of entity become name of relation Attribute of entity becomes attributes of relation Primary key of relation becomes primary key of relation
- 3. Mapping Entities into Relational Model One-to-many Insert primary key of entity having cardinality one into entity having cardinality many One-to-one Having minimum cardinality one on one side and zero on other, Insert primary key of entity having cardinality one into entity having cardinality zero One-to-one Having minimum cardinality zero on both sides, Insert primary key of entity any entity into other entity Many-to-many Create new relationship and put primary keys of both tables