Relationship Examples

This section shows the graphic representation of various relationship properties.

One-to-many relationship	Description
	Each division may have zero or more employees Each employee may belong to zero or one division
	Each division must have one or more employees Each employee may belong to zero or one division
	Each division may have zero or more employees Each employee must belong to one and only one division
	Each division must have one or more employees Each employee must belong to one and only one division
	Each division may have zero or more employees Each employee must belong to one and only one division Each employee is identified uniquely by division number and employee number
	Each division must have one or more employees Each employee must belong to one and only one division Each employee is identified uniquely by division number and employee number

One-to-one relationship	Description
	Each team works on zero or one project Each project is managed by zero or one team
	Each team works on one and one project only Each project is managed by zero or one team
	Each team works on zero or one project Each project is managed by one and one team only

One-to-one relationship

Description

Each team works on zero or one project

Each project is managed by zero or one team

Each team works on one and one project only

Each project is managed by zero or one team

Each team works on zero or one project

Each project is managed by one and one team only

Many-to-many relationship	Description
	Each division may have zero or more employees Each employee may belong to zero or more divisions
	Each division must have one or more employees Each employee may belong to zero or more divisions
	Each division may have zero or more employees Each employee must belong to one or more divisions
	Each division must have one or more employees Each employee must belong to one or more divisions