Chapter 4 - Relational model. The main contents of this chapter include all of the following: Relational model concept, relational data model, relational database, relation schema, relational algebra, relational query languages,. | Chapter 4 Relational Model Relational Model Concept Relational database: a set of relations Each relation resembles a table of values Relation: made up of 2 parts ◦ Instance: a table, with rows and columns. ◦ Schema: specifies name of relation, plus name and type of each column. TheUser terms commonly Model usedProgrammer Row Column Table Tuple Attribute Relation Record Field File Relational Data Model The relational model uses a collection of tables to represent both data and the relationships among those data. Each relation resembles a table of values Tables are logical structures maintained by the database manager. Ex: STUDENT (NO., NAME, DATE_OF_BIRTH, GENDER) Relation Set of attributes Relational Database Ex: ◦ A row is called tuple. ◦ A column is called attribute. ◦ The table is called relation. Relational Database For each column of a table, there is a set of possible values called its domain. Domain is the set of valid values for .
