INST 311 Lecture Notes - Lecture 12: Data Integrity, Query Language, Relational Algebra

• School: University of Maryland
• Department: Information Studies
• Course: INST 311
• Professor: Fenlon

Document Summary

Relational data model is the primary data model, which is used widely around the world for data storage and processing. This model is simple and it has all the properties and capabilities required to process data with storage efficiency. Tables in relational data model, relations are saved in the format of tables. A table has rows and columns, where rows represents records and columns represent the attributes. Tuple a single row of a table, which contains a single record for that relation is called a tuple. Relation instance a finite set of tuples in the relational database system represents relation instance. Relation schema a relation schema describes the relation name (table name), attributes, and their names. Relation key each row has one or more attributes, known as relation key, which can identify the row in the relation (table) uniquely. Attribute domain every attribute has some pre-defined value scope, known as attribute domain.