Editing Composite key (section)

{{Short description|Candidate key with two or more attributes in a database}}
{{more sources needed|date=February 2024}}
In [[Data modeling|database design]], a '''composite key''' is a [[candidate key]] that consists of two or more attributes,<ref>{{cite book |last1=Connolly |first1=Thomas M. |last2=Begg |first2=Carolyn E. |title=Database systems: a practical approach to design, implementation, and management |date=2015 |publisher=Pearson |location=Boston Columbus Indianapolis |isbn=978-1-292-06118-4 |page=416 |edition=6., global |chapter=12.3.4 Keys}}</ref><ref>{{cite book |last1=Elmasri |first1=Ramez |last2=Navathe |first2=Sham |title=Fundamentals of database systems |date=2017 |publisher=Pearson |location=Boston Columbus Indianapolis New York San Francisco Hoboken Amsterdam Cape Town Dubai London Madrid Milan Munich Paris Montreal Toronto Delhi Mexico City São Paulo Sydney Hong Kong Seoul Singapore Taipei Tokyo |isbn=978-1-292-09761-9 |page=661 |edition=Seventh, global |chapter=17.4 Indexes on Multiple Keys}}</ref><ref>{{cite book |last1=Coronel |first1=Carlos |last2=Morris |first2=Steven |title=Database systems: design, implementation, and management |date=2015 |publisher=Cengage Learning |isbn=978-1-305-62748-2 |page=770 |edition=12e |chapter=Glossary}}</ref> (table columns) that together uniquely identify an entity occurrence (table row).  

A '''compound key''' is a composite key for which each attribute that makes up the key is a [[foreign key|foreign]] key in its own right.<ref>{{Citation |last=Duncan |first=Joyce |title=Step 340 — Enhance Required Logical Data Model |date=1995 |work=SSADM in Practice: A Version 4 Text |pages=61–70 |editor-last=Duncan |editor-first=Joyce |url=https://link.springer.com/chapter/10.1007/978-1-349-10341-6_6 |access-date=2024-10-25 |place=London |publisher=Macmillan Education UK |language=en |doi=10.1007/978-1-349-10341-6_6 |isbn=978-1-349-10341-6 |last2=Rackley |first2=Lesley |last3=Walker |first3=Alexandria |editor2-last=Rackley |editor2-first=Lesley |editor3-last=Walker |editor3-first=Alexandria|url-access=subscription }}</ref><ref>{{Citation |last=Sikora |first=Z. M. |title=Implementing a Design |date=1997 |work=Oracle Database Principles |pages=74–84 |editor-last=Sikora |editor-first=Z. M. |url=https://link.springer.com/chapter/10.1007/978-1-349-14693-2_7 |access-date=2024-10-25 |place=London |publisher=Macmillan Education UK |language=en |doi=10.1007/978-1-349-14693-2_7 |isbn=978-1-349-14693-2|url-access=subscription }}</ref>