Database Reference
In-Depth Information
to ensure that each account representative can deliver the level of service the organization
requires, the policy stipulates that he cannot be assigned to more than 15 customers at the
same time. Based on this scenario, you can infer that the degree of participation for the
EMPLOYEES table is (1,1) and the degree of participation for the CUSTOMERS table is
(0,15).
Onceyou'veidentifiedthedegreeofparticipationforaparticulartable,addtheinformation
to the relationship diagram. Designate the degree of participation
over
the connection
line of the appropriate table.
Figure 10.62
shows the revised relationship diagram for the
EMPLOYEES and CUSTOMERS tables.
Figure 10.62. Designating the degree of participation for the EMPLOYEES and
CUSTOMERS tables
Thedegreeofparticipationalsoappliestoaself-referencingrelationship,althoughyoudes-
ignateitfor
the primary key and foreign key fields
inthetable,justasyoudidwiththetype
of participation.
Figure 10.63
shows an updated version of the relationship diagram for the
STAFF table that includes the degree of participation information.
S
TAFF
ID has a degree of participation of (0,12) because a manager can manage up to 12
staffmembers;anewmanagerwhohasn'tyetbeenassignedtoadepartmentorprojectwill
have no (or 0) staff members to manage. The degree of participation for M
ANAGER
ID is
(1,1) because a given staff member is managed by only one manager.
