COMM 205 Lecture Notes - Lecture 5: Foreign Key, Referential Integrity, Sql
Document Summary
No lecture 4 due to class dedicated to netsuite: explain the importance of databases. Databases are a collection of records about various business categories such as transactions, resources, events, people and places. They are a structured collection of data accessed and utilized by many different applications and users; information systems maintain and access the transactions within a database. Data stored in electronic storage devices (e. g. databases) Data redundancy: duplication of data in multiple data files wastes storage; unefficient. Data inconsistency: different representations of data in stored in different places. Comm205 lecture 5: applications cannot access data associated with other applications. Data management systems (dbms) should be able to solve these issues. Data security: deters mistakes and attacks. Data integrity: constraints (e. g. no words in a social insurance number field) Data independence: applications and data can access same data, describe the fundamental concepts of the relational database.
