Associate Entity in Complex M:M
Relational Database is support Binary Relationship and Unary Relationship that is not support Ternary Relationship and N-ary Relationship. To avoid this RDBMS limitation, we need to define a Common Entity and map the attributes into two or more different entities. This Common Entity is called Associate Entity.
An instance, an I.T. Company Technical Department is formed with many Employees. Each Employee is assigned in one or many Projects with one or many Tasks.
Associate Entity Concept is helps to eliminate Data Redundant that define with Composite Primary Key and map Employee, Project and Task entities Primary Key Attributes. Associate Entity Name may be a combination of entities name with XRef word. XRef word is determining (X) Natural Join Dependency (Ref) Reference Entity Type.
This re-designed diagram is representing that an Employee may be assigned in Zero, One or Many Projects and every Project must be operate by One or Many Employees by representing the Connectivity and Cardinality of Relationship Mandatory Symbol.
This re-designed diagram is representing that an Employee may be assigned in Zero, One or Many Projects with Zero, One or Many Tasks and every Project must be operate by One or Many Employees by representing the Connectivity and Cardinality of Relationship Mandatory Symbol.
Relational Database is support Binary Relationship and Unary Relationship that is not support Ternary Relationship and N-ary Relationship. To avoid this RDBMS limitation, we need to define a Common Entity and map the attributes into two or more different entities. This Common Entity is called Associate Entity.
An instance, an I.T. Company Technical Department is formed with many Employees. Each Employee is assigned in one or many Projects with one or many Tasks.
Associate Entity Concept is helps to eliminate Data Redundant that define with Composite Primary Key and map Employee, Project and Task entities Primary Key Attributes. Associate Entity Name may be a combination of entities name with XRef word. XRef word is determining (X) Natural Join Dependency (Ref) Reference Entity Type.
This re-designed diagram is representing that an Employee may be assigned in Zero, One or Many Projects and every Project must be operate by One or Many Employees by representing the Connectivity and Cardinality of Relationship Mandatory Symbol.
This re-designed diagram is representing that an Employee may be assigned in Zero, One or Many Projects with Zero, One or Many Tasks and every Project must be operate by One or Many Employees by representing the Connectivity and Cardinality of Relationship Mandatory Symbol.
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