2. BACHMAN STYLE/NOTATION
• Entity sets – no more ovals… attributes listed inside the box
• No more diamonds; a line connecting two boxes indicate relationship between
two entity sets.
3. BACHMAN STYLE/NOTATION
Employee Office
is assigned to
Every employee is assigned to exactly one office and every
office is assigned one employee.
One-to-one relationship with total participation at both ends.
4. BACHMAN STYLE/NOTATION
• Every cargo aircraft serves one or more distribution centers and
every center is served exactly one aircraft.
• One-to-many relationship with total participation at both ends.
Cargo Aircraft Distribution center
serves
5. BACHMAN STYLE/NOTATION
• An analyst maybe in charge of many projects(or may not be in charge of any)
and every project has exactly one systems analyst in charge.
• One-to-many relationship with total participation at one end(project) and
partial at the other(analyst).
System Analyst Project
is in charge of
6. BACHMAN STYLE/NOTATION
• A machine may or may not be undergoing scheduled maintenance and every
scheduled maintenance always refers to exactly one machine.
• One-to-one relationship with total participation at one end(scheduled
maintenance) and partial at the other (Machine).
Machine Scheduled
Maintenance
is undergoing
7. BACHMAN STYLE/NOTATION
• Every sales person is assigned to call one or more customers, and every
customer has one or more sales persons assigned to call.
• Many-to-many relationship with total participation at both ends.
Sales Person Customer
is assigned to call on
8. BACHMAN STYLE/NOTATION
• Every home office is permitted to one or more employees, and an employee
or may not be permitted to a home office.
• One-to-many relationship with total participation at one end(Home Office)
and partial at the other end(Employee).
Home Office Employee
is permitted to
9. BACHMAN STYLE/NOTATION
Partner Participation is mandatory, with at most
one unit per partner.
…(1,1)
Partner Participation is optional, with at most
one unit per partner: one-to-?
…(0,1)
Partner Participation is mandatory, with possibly
many units per partner: many-to-?
…(1,*)
Partner Participation is optional, with possibly
many units per partner: many-to-?
…(0,*).
