Editing Relational database (section)

==Relational model==
{{Main|Relational model}}
A relational model organizes data into one or more [[table (database)|tables]] (or "relations") of [[Column (database)|columns]] and [[row (database)|rows]], with a [[unique key]] identifying each row. Rows are also called [[Record (computer science)|records]] or [[tuple]]s.<ref>{{cite web |title=A Relational Database Overview |website=oracle.com |url=https://docs.oracle.com/javase/tutorial/jdbc/overview/database.html}}</ref> Columns are also called attributes. Generally, each table/relation represents one "entity type" (such as customer or product). The rows represent instances of that type of [[entity]] (such as "Lee" or "chair") and the columns represent values attributed to that instance (such as address or price).

For example, each row of a class table corresponds to a class, and a class corresponds to multiple students, so the relationship between the class table and the student table is "one to many"<ref>{{Citation |date=1992 |title=A universal relation model for a nested database |work=The Nested Universal Relation Database Model |series=Lecture Notes in Computer Science |volume=595 |pages=109–135 |place=Berlin, Heidelberg |publisher=Springer Berlin Heidelberg |doi=10.1007/3-540-55493-9_5 |isbn=978-3-540-55493-6 |url=http://dx.doi.org/10.1007/3-540-55493-9_5 |access-date=2020-11-01|url-access=subscription }}</ref>