CA ERwin supports three types of logical relationships between entities:
- Identifying relationships
- Many-to-many relationships
- Non-identifying relationships
This article explains these three relationship types in more detail in the following sections.
In ERwin, an identifying relationship is represented by a solid line and is the relationship between the primary key of the parent entity and the primary key of the child entity.
In an identifying relationship, the foreign key migrates above the line and becomes part of the primary key of the child entity.
Many-to-many relationships define a relationship between two entities where a parent row might have many children and vice-versa:
Non-identifying relationships are represented by a dashed line in ERwin. It is the relationship between the primary key of the parent entity and a non-key attribute of the child table.