CSIT 355 Lecture Notes - Lecture 1: Xml, Nosql, Database
Document Summary
Data: known facts that can be recorded and have an implicit meaning. Mini-world: some part of the real world about which data is stored in a database. Database management system (dbms): a software package/system to facilitate the creation and maintenance of a computerized database. Database system: the dbms software together with the data itself. Program-data independence: allows changing data structures and storage organization without having to change the dbms access programs. Data model: a set of concepts to describe the structure of a data base, the operations for manipulating these structures, and certain constraints that the database should obey. Constructs are used to define the database structure. Constructs typically include elements (and their data types) as well as groups of elements (e. g. entity, record, table), and relationships among such groups. Constraints specify some restrictions on valid data; these constraints must be enforced at all times.
