COMM 205 Lecture Notes - Lecture 10: Data Redundancy, Data Integrity, Unique Key
Document Summary
Some is data and some is info. Collection of records of many business categories (entities) such as: Maintain and access the transactional data in databases. Should be stored and managed efficiently in electronic storage devices. There is data consistency (or data integrity) Wastage of storage space and inefficient processing. Various copies of the data do not agree. Different representations of the same piece of data in diff. Application can"t access data associated with other applications. Structured collection of data accessed and utilized by many different applications. Software used by users and applications to interact with database. Used to create, manage, maintain, and manipulate a database. Fields whose values uniquely identifies each row. Each table must have a primary key that uniquely identifies each row. Pk that consists of more than one field. Primary key that consist of only one field. Database usually has more than one table. Used to create logical relationships between tables.
