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Uses a two-dimensional table of rows and columns of data oRows are recordsoColumns are fieldsData dictionary: Stores definitionsoData types for fields, default values, and validation rules for data in eachfieldPrimary keyoUniquely identifies every record in a relational databaseForeign keyoField in a relational table that matches the primary key column of another table oUsed to cross-reference tablesNormalization oImproves database efficiency by eliminating redundant data Ensures that only related data is stored in a tableoGoes through different stages from first normal form (1NF) to fifth normal form (5NF)Retrieves data from tables using operations that pick and combine data from one or more tables oSelectoProjectoJoinoIntersectionoUnionoDifferenceComponents of a DBMS Database engineData definitionData manipulationApplication generationData administrationDatabase Engine
Heart of DBMS software Responsible for data storage, manipulation, and retrieval Converts logical requests from users into their physical equivalents oBy interacting with other components of the DBMSData Definition Creates and maintains the data dictionary Defines the structure of files in a databaseMakes changes to a database’s structureoAdding and deleting fieldsoChanging field size and data typeData Manipulation Used to add, delete, modify, and retrieve records from a database Uses a query languageoStructured Query Language (SQL) Standard fourth-generation query language that consists of several keywords specifying actions to takeoQuery by example (QBE)Involves requesting data from a database by constructing a statement formed by query formsApplication Generation Designs elements of an application using a databaseoData entry screensoInteractive menusoInterfaces with other programming languages Used by IT professionals and database administratorsData Administration Used for the tasks backup and recovery, security, and change managementUsed to determine who has permission to perform certain functionsoSummarized as create, read, update, and delete (CRUD)Database administrator (DBA) oHandles database design and managementSetting up databaseEstablishing security measures to determine users’ access rightsDeveloping recovery procedures when data is lost or corrupted
Evaluating database performanceAdding and fine-tuning database functionsRecent Trends in Database Design and Use Data-driven websiteoInterface to a databaseoRetrieves data and allows users to enter dataoImproves access to informationoGives users more current information from a variety of data sourcesDistributed database: Stores data on multiple servers throughout an organization Approaches to setting up a DDBMSoFragmentation: Addresses how tables are divided among multiple locationsoReplication: Each site stores a copy of the data in the organization’s databaseoAllocation: Combines fragmentation and replication, with each site