7-2 HOMEWORK ACTIVITY 1
7-2 Homework Activity: Module 7
Southern New Hampshire University
DBMS
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7-2 HOMEWORK ACTIVITY 2
A Database Management System (DBMS) is a conglomerate of various items that enable a user
to enter, edit and analyze data. Usually a database is managed by someone considered to be the
Database Administrator (DBA). Typically, a DBMS will contain an interface for users, a database
administrator, related systems, and also data manipulation language, schema, ad subschema and a
physical data repository.
Keys
Key fields are fields that provide a referencing source for the database. There are four types of
keys used and they are primary keys, candidate keys, foreign keys, and secondary keys. The
primary key is just that, the primary key and the key that uniquely identifies a field. This is
sometimes a string of number that are unique like a social security number is to an American
citizen. A candidate key is like a primary key but is one that can be selected for example in
Human Resources we can use either a social security number or employee number as a unique
identifier. A foreign key is a key that is found within another table and must match the primary
key in the source table. The major difference between a foreign key and a primary key is that the
primary key must be unique and the foreign does not. A secondary key is a field that is not
unique but like a primary key can be used to access fields for analysis.
Entity Relationship Diagram
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7-2 HOMEWORK ACTIVITY 3
In the above Entity Relationship Diagram, it shows the relationship between the entry of
demographic information pertaining to the employee and how that provides a data point for the
actual employee as utilized within a Human Resources department utilizing a HRIS.
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