The utilization of databases is now so widespread that virtually every technology and product relies on databases and DBMSs for its development and commercialization, or even may have DBMS software embedded in it. A general-purpose DBMS is typically a complex software system that meets many usage requirements to properly maintain its databases which are often large and complex. The term database system implies that the data are managed to some level of of quality quality (measured in terms of accuracy, availability, usability, and resilience) and this in turn often implies the use of a general-purpose database management system (DBMS). The database data collection with DBMS is called a database system. The term database is correctly applied to the data and their supporting data structures, and not to the database management system (DBMS). The data are typically organized to model relevant aspects of reality (for example, the availability of rooms in hotels), in a way that supports processes requiring this information (for example, finding a hotel with vacancies). Contents Articles Database 1 Entity – relationship model 24 Database design 32 Relational database 35 Relational model 39 Binary relation 49 Database normalization 55 First normal form 63 Second normal form 67 Third normal form 70 Boyce – Codd normal form 73 Fourth normal form 78 Fifth normal form 80 Domain/key normal form 83 Sixth normal form 85 Relation (database) 87 Functional dependency 88 Multivalued dependency 90 Join dependency 92 Concurrency control 93 References Article Sources and Contributors 101 Image Sources, Licenses and Contributors 104 Article Licenses License 105 Database Database A database is an organized collection of data.