Alan Freedman -- The Computer Language Company - Computer Desktop Encyclopedia
Computer Desktop Encyclopedia
Longest-Running Tech Reference on the Planet

A CDE Definition

You'll love The Computer Desktop Encyclopedia (CDE) for Tech Term of the Day (TTOD)

LOOK UP ANOTHER TERM


foreign key

In relational databases, it is a field in one table that is indexed in another. Foreign keys provide the building blocks for relating tables. For example, in a customer order table, the salesperson field might contain an employee number. That field would be a foreign key in the table, because the employee table would be indexed on employee number. See entity relationship model.




Foreign Keys
Note the "FK" indications in this Erwin entity relationship modeling program. Every foreign key is a field in one table that is indexed in another. (Example courtesy of Logic Works, Inc.)






entity relationship model

A database model that describes the attributes of entities and the relationships among them. An entity is a file (table). Today, ER models are often created graphically, and software converts the graphical representations of the tables into the SQL code required to create the data structures in the database. See data model and dimensional modeling.




Building an Entity Relationship Model
The Erwin modeling program from CA Technologies stands for Entity Relationship for Windows. In this order processing example, the tables for customers and orders are drawn graphically, and Erwin turns the graph into the appropriate SQL code for the target database. (Example courtesy of CA Technologies, Inc.)






Personal Use Only

Before/After Your Search Term
BeforeAfter
Forceforeign language characters
Force Quitforensically clean
Force Touchforensics
force touchingForeRunner
Ford SYNCforest
FORE SystemsForest & Trees
foreground/backgroundforests and trees
foreign exchange serviceforestware
foreign filefork
foreign formatforked

Terms By Topic
Click any of the following categories for a list of fundamental terms.
Computer Words You Gotta KnowSystem design
Job categoriesUnix/Linux
Interesting stuffPersonal computers
InternetIndustrial Automation/Process Control
Communications & networkingAssociations/Standards organizations
HistoryDesktop publishing
Audio/VideoGraphics
MainframesSecurity
ProgrammingHealthcare IT
System design