If access to data by multiple users is not required. If there are stringent real-time requirements that may not be met because of DBMS overhead. When a DBMS may be unnecessary - If the database and applications are simple, well defined, and not expected to change. Overhead for providing generality, security, recovery, integrity, and concurrency control. Support of multiple views of the data Each user may see a different view of the database, which describes only the data of interest to that user.Īdditional Benefits of Database Technology 18 Controlling redundancy in data storage and in development and maintenence efforts.Įnforcing integrity constraints on the database.Ĭlasses of Database Users (A) Workers on the scene Persons whose job involves daily use of a large database.ĭatabase administrators (DBAs) Database designers End users Casual users Parametric (nave) users Sophisticated end users System analysts and application programmers 21 (B) Workers behind the scene Persons whose job involves design, development, operation and maintenance of the DBMS software and system environment.ĭBMS designers and implementers Tool developers Operators and maintenance personnel 22 (No Transcript) 23 5 When not to use a DBMS 24 Main inhibitors (costs) of using a DBMS - High initial investment and possible need for additional hardware. Insulation between programs and data Called program-data independence.Īllows changing data storage structures and operations without having to change the DBMS access programs.ĭata Abstraction A data model is used to hide storage details and present the users with a conceptual view of the database. This allows the DBMS software to work with different databases. Some mini-world entities - STUDENTs - COURSEs - SECTIONs (of COURSEs) - (academic) DEPARTMENTs - INSTRUCTORs 10 Some mini-world relationships - SECTIONs are of specific COURSEs - STUDENTs take SECTIONs - COURSEs have prerequisite COURSEs - INSTRUCTORs teach SECTIONs - COURSEs are offered by DEPARTMENTs - STUDENTs major in DEPARTMENTs NOTE The above could be expressed in the ENTITY RELATIONSHIP data model. Sometimes, the applications are also included.Īlternate Definition Database An integrated collection of more-or-less permanent data.Ĭoncerns of DBMS integrity consistency redundancy (its bad, but replication is good) security 8 2.Įxample of a Database (with a Conceptual Data Model) 9 Mini-world for the example Part of a UNIVERSITY environment. Database Management System By Navathe Ppt Software Package Systemĭatabase System The DBMS software together with the data itself.
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