Relationship Examples

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Below are several examples of Logical Data Model relationships and their meaning, click the links to expand the examples.

 

One-to-many relationships

Each division can have zero or more employees.

 

Each employee belongs to zero or 1 division.

 

This is a non-identifying relationship.

Each division must have 1 or more employees.

 

Each employee belongs to zero or 1 division.

 

This is a non-identifying relationship.

Each division can have zero or more employees.

 

Each employee belongs to 1 division.

 

This is a non-identifying relationship.

Each division must have 1 or more employees.

 

Each employee belongs to 1 division.

 

This is a non-identifying relationship.

 

One-to-one relationships

Each team works on zero or one project.

 

Each project is being worked on by no team or just one teams.

 

This is a non-identifying relationship.

Each team works on one project.

 

Each project is being worked on by no team or just one team.

 

This is a non-identifying relationship.

Each team works on zero or one project.

 

Each project is being worked on by one team.

 

This is a non-identifying relationship.

Each team works on one project.

 

Each project is being worked on by one team.

 

This is a non-identifying relationship.

 

Many-to-many relationships

Each employee belongs to zero or more divisions.

 

Each division has zero or more employees.

 

This is a non-identifying relationship.

Each employee must belong to 1 or more divisions.

 

Each division has zero or more employees.

 

This is a non-identifying relationship.

Each employee belongs to zero or more divisions.

 

Each division has 1 or more employees.

 

This is a non-identifying relationship.

Each employee must belong to 1 or more divisions.

 

Each division has 1 or more employees.

 

This is a non-identifying relationship.