CIS-3750 Lecture Notes - Lecture 3: Foreign Key, Unique Key, Database Design
1 Sep 2016
School
Department
Course
Professor
Document Summary
Relation- similar to the mathematical concept of a set, is a two dimensional table arranged in rows and columns. Relational database- is a collection of relations (rows and columns), where relation is a mathematical term for a table. In a relational database, each row must be uniquely identified. There must be a primary key, so that each row can be designed (ex- student identifier, phone numbers) Designating the right primary key is important in database design. The tables in a relational database are connected or related by means of the data in the tables. This connection is between a pair of values, a primary key and a foreign key. Structured query language (sql)- supports set processing (multiple records at a time) when creating a relational model. Sql is a data definition language (ddl), (to define a database), a data manipulation language (dml),(to query and maintain a database), and a data control language (dcl), (to control access).
