functions of a DBMS questions and answers latest updated

functions of a DBMS questions and answers latest updated Data dictionary management DBMS stores definitions of data elements and relationships (metadata) in a dictionary. DBMS looks up required data component structures and relationships. Changes automatically recorded in the dictionary. DBMS provides data abstraction and removes structural and data dependency. Data Storage Management DBMS creates and manages complex structures required for data storage Also stores related data entry forms, screen definitions, report definitions, etc. Performance tuning: activities that make the database perform more efficiently DBMS stores the database in multiple physical data files Data transformation and presentation DBMS transforms data entered to conform to required data structures DBMS transforms physically retrieved data to conform to user's logical expectations Security management DBMS creates a security system that enforces user security and data privacy Security rules determine which users can access the database, which items can be accessed, etc. Uses multiple "tools" to manage: Transaction log Access control / privileges table Multiuser access control Allows many (thousands) of users to access the same data at the same time while maintaining all the changes as they are made. DBMS uses sophisticated algorithms to ensure concurrent access does not affect integrity Enforces transaction management and concurrency control Backup and recovery management DBMS provides backup and data recovery to ensure data safety and integrity Recovery management deals with recovery of database after a failure Critical to preserving database's integrity Data integrity management DBMS promotes and enforces integrity rules Minimizes redundancy Maximizes consistency Data relationships stored in data dictionary used to enforce data integrity Integrity is especially important in transaction-oriented database systems Database access language and application programming interfaces DBMS provides access through a query language Query language is a nonprocedural language Structured Query Language (SQL) is the de facto query language Standard supported by majority of DBMS vendors Database communication interfaces Current DBMSs accept end-user requests via multiple different network environments Communications accomplished in several ways: End users generate answers to queries by filling in screen forms through Web browser DBMS automatically publishes predefined reports on a Web site DBMS connects to third-party systems to distribute information via e-mail