The Entity Relationship Diagram, Essay Example

An ERD is graphical expression of the general logical structure of a company’s database, the database of a company can be graphically represented using the following components:

Components of an E-R diagram.

• rectangles are used to represent the entity datasets
• ellipses on the other hand are used tom represent the main attributes where as
• diamonds are used to represent the relationship sets and
• lines are used to link the entity sets to the relationship sets

It is important to note in the text one can find the lines directed with arrows on the ends, this is always used to signify the mapping cardinalities for the relationship sets.