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IMS1907 Database Systems Week 2 Types of Database Systems Impact of Database Systems The amount of information being collected and stored is almost beyond comprehension – and its growing Stored information is being used for more purposes than were conceivable ten (or even five) years ago Databases are used at every level of society – individuals, small business, national organisations, global corporations, governments… They affect many aspects of our everyday lives Monash University 2004 2 Impact of Database Systems Databases are used in – monitoring and improving business operations – tracking customers and their behaviour – tracking and despatching emergency service vehicles – monitoring communications with space vehicles – making decisions (business and otherwise) – generating spam – performing surgical procedures – many other applications from the mundane to miraculous Monash University 2004 3 Impact of Database Systems Critical to business productivity and profitability Critical to individual life and safety Instrumental in economic and social stability Can affect governments It essential that information is accurate, up-to-date and consistent Not always easy when there are so many databases of so many types storing different versions of similar or the same information Monash University 2004 4 A Brief History of Database Systems 3000BC(?) knotted and coloured string, marks on clay 2000BC(?) papyrus-based recording 200BC(?) paper-based technologies 1950 file processing systems 1970 hierarchical DBMS,network DBMS (first generation DBMS), Codd’s relational model Monash University 2004 5 A Brief History of Database Systems 1980 1990 2000+ relational DBMS (second generation DBMS), SQL internet, data warehouses, object-oriented DBMS, distributed databases more complex data structures, universal servers, centralised databases, contentaddressable storage, AI, data mining, mobile technologies, super computers… Monash University 2004 6 Types of Database Systems Personal Databases Workgroup Databases Department Databases Enterprise Databases Internet, Intranet, and Extranet Databases Data warehouses Monash University 2004 7 Personal Databases Support single user PCs, laptops, personal digital assistants (PDA), mobile phones… Improve personal productivity Can be difficult to share data of interest to other users Used in small organisations when need to share data is unlikely MS Access, Oracle Personal, FoxPro… Monash University 2004 8 Personal Databases Considerations for developing personal databases include – develop in-house vs outside vendor – developed by end user or IT staff – data requirements, database design requirements – which commercial DBMS? – can data be synchronised with other databases? How? – who is responsible for data in personal database? Monash University 2004 9 Workgroup Databases Workgroups – small teams (typically less than 25 people) collaborating on the same project or application or group of similar projects or applications Workgroup database – supports collaborative effort – allows change tracking, ease of data sharing – allows concurrent user updating Typically stored on database server and provided to users via a Local Area Network (LAN) Monash University 2004 10 Workgroup Databases Considerations for developing workgroup databases include – data management issues - data security, data integrity – multiple user views, multiple subscribing to databases – database design optimisation for and between different group members – how can concurrent access needs be met without compromising data integrity? – where should processing take place – client vs server? Monash University 2004 11 Department Databases Support functional units of an organisation – sales, personnel, marketing, manufacturing, accounting Contain data necessary – to perform functions and processes within specific activity area – to answer questions relevant to specific activity area Large numbers of users often in geographically dispersed locations Possibly the most common type of database Monash University 2004 12 Department Databases Considerations for developing department databases include – design of DB and environment for adequate performance with large number of users and user transactions – security protecting against unauthorised access to or distribution of sensitive data – which DB and application development tools are appropriate for complex environment? Monash University 2004 13 Department Databases Considerations for developing department databases include – does similar data exist elsewhere in organisation? How can we manage redundancy, consistency, metadata? – is a distributed database system needed? Are users geographically dispersed? Does size of DB require storage on several systems? – should database be web-enabled? Incorporated in intranet environment? Monash University 2004 14 Enterprise Databases Scope covers an entire organisation (or at least many different departments!) Support organisation-wide operations, decision making Organisation may have several enterprise databases – enterprise DB not truly inclusive of all organisational data – single operational DB may be impractical due to performance difficulties, diverse needs, metadata definition problems Enterprise Resource Planning (ERP) systems, data warehouses Monash University 2004 15 Enterprise Databases Considerations for developing enterprise databases include – how should data be distributed throughout the various locations in the organisation? – how can standards be developed and maintained throughout the organisation for data names, definitions, formats and related issues? – what do we need to do to ensure successful integration of numerous data sources including legacy systems? Monash University 2004 16 Internet, Intranet and Extranet Databases The proliferation of the Internet has been one of the most significant drivers of technological and business change – highly competitive – improved customer information – eliminate traditional marketing/distribution channels – employee relationship management – direct sales – ticket booking – e-auctions, share trades Monash University 2004 17 Internet, Intranet and Extranet Databases Need for database support, universal data access Internet provides easy connection across multiple platforms Browser-based applications utilise standard interface – lower development costs Web-enabled databases allow users to ask unique and specific questions and receive answers based on current information Online shopping, airline ticket booking, auctions These are mostly BC (business-to-consumer) Monash University 2004 18 Internet, Intranet and Extranet Databases Businesses also deal with other businesses BB Traditionally they used electronic data interchange (EDI) as a means to trade information Extranets are internet-enabled but access is not universal – utilise XML to provide standard format They allow businesses to gain limited access to and use of each others information Fosters relationships via more efficient exchanges Often gives access to part of company intranet Monash University 2004 19 Internet, Intranet and Extranet Databases Businesses often use internet technology to create internal private networks – intranets Allow exchange and management of information within an organisation – HR, financial, programs, training, news… Only internal access to data is allowed Can be used to connect to internet Requires additional technology to restrict external access Monash University 2004 20 Internet, Intranet and Extranet Databases Considerations for developing web-enabled databases include – the type of technology used to link web applications to client databases (middleware, protocols…) – the measures and technology necessary to ensure security and privacy (firewalls, passwords, encryption…) – the staggering amount of data generated via the internet – maintenance of data quality in environment where data sources are external Monash University 2004 21 Types of Database Users Naïve users – unsophisticated – interact via application programs – fill in forms, view reports Application programmers – usually computer professionals – use methodologies, tools, languages (3GL, 4GL) to create interfaces Monash University 2004 22 Types of Database Users Sophisticated users – interact with DBMS without program interface – use database query language via a query processor – use online analytical processing tools, data mining tools Specialised users – who write specialised programs outside traditional DBMS – computer-aided design (CAD) systems, knowledgebased systems (KBS), expert systems, complex data type storage systems, environment-modelling systems Monash University 2004 23 References Elmasri, R. and Navathe, S.B., (2000), Fundamentals of Database Systems, (3rd edn.), Addison-Wesley, Reading, Massachusetts, USA. Hoffer, J.A., Prescott, M.B. and McFadden, F.R., (2002), Modern Database Management, (7th edn.), Pearson Education Inc., Upper Saddle River, NJ, USA. Murphy, B., (1999), Data Downtime Dilemma, accessed 5th July 2004 at http://www.findarticles.com/p/articles/mi_m0SMG/is_3_19/ai_593 29322. Silberschatz, A., Korth, H.F. and Sudarshan, S., (2002), Database System Concepts, (4th edn.), McGraw-Hill Companies Inc., Boston, Mass., USA. Monash University 2004 24