This document describes a weak entity relationship diagram (ERD) where the TEAMS entity is a weak entity because part of its primary key consists of attributes from the parent DEPARTMENT entity's primary key. The ERD shows EMPLOYEE and DEPARTMENT as strong entities with their own primary keys, and TEAMS as a weak entity with a composite primary key containing its own attribute and foreign keys linking to the primary keys of DEPARTMENT and EMPLOYEE.

1. Weak Entity ERD
By: Nicole Gaehle and Leah Kinnamon
This is a weak entity because a portion of the primary key is made up of a parent entity primary key.
EMPLOYEE
PK EMP_NUM
LNAME
FNAME
CONTACT
ADDRESS
CITY
STATE
ZIP
DEPARTMENT
PK DEPT_NAME
DEPT_LOCATION
DEPT_PHONE
TEAMS
PK,
FK1
DEPT_NAME
PK,
FK2
EMP_NUM
belongs in contains many