What are the critical relationship types in a Data Model?

1.	What are the critical relationship types in a Data Model?
Answer» A relationship is normally used for connecting parent and child tables. There are 3 types of CRITICAL relationships in a data model, they are: Identifying: In this type, a reference column of a child’s table these are connected by a thick line is part of the primary key of the parent table which helps in identifying the records. This relationship is usually replaced by a thick line. These are called identifying because the FOREIGN key can never change as it becomes part of the primary key. A child object cannot exist if there is no parent object. Non-identifying: Here, the reference column of a child table is not part of the primary key of the parent. This relationship is represented by a dotted line. This relationship can be optional or mandatory depending on the requirements. It MEANS that the foreign key columns can (if optional) or cannot allow (if mandatory) NULL. Self-recursive: Here, a STANDALONE column is connected to a primary key in the same table. This relationship is between different column instances of the same entity type.

Answer»

A relationship is normally used for connecting parent and child tables. There are 3 types of CRITICAL relationships in a data model, they are:

Identifying: In this type, a reference column of a child’s table these are connected by a thick line is part of the primary key of the parent table which helps in identifying the records. This relationship is usually replaced by a thick line. These are called identifying because the FOREIGN key can never change as it becomes part of the primary key. A child object cannot exist if there is no parent object.
Non-identifying: Here, the reference column of a child table is not part of the primary key of the parent. This relationship is represented by a dotted line. This relationship can be optional or mandatory depending on the requirements. It MEANS that the foreign key columns can (if optional) or cannot allow (if mandatory) NULL.
Self-recursive: Here, a STANDALONE column is connected to a primary key in the same table. This relationship is between different column instances of the same entity type.

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