Database Keys

Two types of key are used to access tables in a relational database: Primary Keys and Foreign Keys.

  • A Primary Key uniquely identifies a record in a table
  • A Foreign Key accesses data in some other related table via its Primary Key

Topics:

Topic

Detail

See also

General Usage

In Enterprise Architect, Primary Keys and Foreign Keys are represented by stereotyped UML attributes and operations

The following example shows a data model that includes both Primary Key and Foreign Key columns

 

Example

A Physical data model defined using a UML Profile that includes Primary and Foreign Keys

A Physical data model defined using a UML Profile that includes Primary and Foreign Keys

 

Primary Key

In each table, one of the columns is designated as the Primary Key, indicated by the PK label beside the column, and a corresponding Primary Key Operation

 

Foreign Keys

Foreign Keys are shown denoted by the FK labels

 

Association Notation

The Association that defines a Foreign Key relationship between SalesPerson and Customer uses the Information Engineering notation; this is one of three notations that Enterprise Architect  supports to help Data Modelers distinguish cardinality in relationships

Enterprise Architect also supports:

  • IDEF1X notation
  • UML notation

 

Learn more: