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Databases - Coggle Diagram

- - - - Database which consists of multiple databases that are connected with each other and are spread across different physical locations. The data that is stored on various physical locations can thus be managed independently of other physical locations. The communication between databases at different physical locations is thus done by a computer network. Stores logically related database over physically independent sites
      - DDB
        
        Date's 12 commandments
        
        Replication transparency
        
        Distributed query processing
        
        Fragmentation transparency
        
        Distributed transaction processing
        
        Location transparency
        
        Hardware independence
        
        Failure Independence
        
        Operating system independence
        
        Central site independence
        
        Network Independence
        
        Local site independence
        
        Database independence
        
        Homogenous
        
        Integrate one type of centralized DBMS over the network
        
        Heterogenous
        
        Integrate different types of centralized DBMSs over a network. Eg) SQL, MySQL, Oracle
        
        Disadvantages
        
        Security and Control
        
        Data Communications
        
        Remote Data
        
        Complex
        
        Management
        
        Setup
        
        Advanatages
        
        Reliability
        
        Redundant copies
        
        Improved communications
        
        Speed
        
        Multiple/Parallel processing
        
        Located near site with greatest demand
        
        Transparency
        
        Hides complexities of distributed database
        
        Featurs
        
        Location
        
        Fragmentation
        
        Heterogeneity
        
        Allows end users to feel like only database user
        
        Components
        
        Communications media
        
        Transaction Processor - application manager or transaction manager
        
        Network hardware and software components
        
        Data Processor - data manager
        
        Computer workstations
    - - Shares database’s logical processing among physically, networked independent sites