View
238
Download
0
Category
Tags:
Preview:
Citation preview
IMS1907 Database Systems
Week 2
Types of Database Systems
Monash University 2004 2
The amount of information being collected and stored is almost beyond comprehension – and its growingStored information is being used for more purposes than were conceivable ten (or even five) years agoDatabases are used at every level of society– individuals, small business, national organisations,
global corporations, governments…They affect many aspects of our everyday lives
Impact of Database Systems
Monash University 2004 3
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
Impact of Database Systems
Monash University 2004 4
Critical to business productivity and profitabilityCritical to individual life and safetyInstrumental in economic and social stabilityCan affect governmentsIt essential that information is accurate, up-to-date and consistentNot always easy when there are so many databases of so many types storing different versions of similar or the same information
Impact of Database Systems
Monash University 2004 5
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 6
A Brief History of Database Systems
1980 relational DBMS (second generation DBMS), SQL
1990 internet, data warehouses, object-oriented DBMS, distributed databases
2000+ more complex data structures, universal servers, centralised databases, content-addressable storage, AI, data mining, mobile technologies, super computers…
Monash University 2004 7
Personal DatabasesWorkgroup DatabasesDepartment DatabasesEnterprise DatabasesInternet, Intranet, and Extranet DatabasesData warehouses
Types of Database Systems
Monash University 2004 8
Support single userPCs, laptops, personal digital assistants (PDA), mobile phones…Improve personal productivityCan be difficult to share data of interest to other usersUsed in small organisations when need to share data is unlikelyMS Access, Oracle Personal, FoxPro…
Personal Databases
Monash University 2004 9
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?
Personal Databases
Monash University 2004 10
Workgroups – small teams (typically less than 25 people) collaborating on the same project or application or group of similar projects or applicationsWorkgroup 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)
Workgroup Databases
Monash University 2004 11
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?
Workgroup Databases
Monash University 2004 12
Support functional units of an organisation– sales, personnel, marketing, manufacturing,
accountingContain 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 locationsPossibly the most common type of database
Department Databases
Monash University 2004 13
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?
Department Databases
Monash University 2004 14
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?
Department Databases
Monash University 2004 15
Scope covers an entire organisation (or at least many different departments!)Support organisation-wide operations, decision makingOrganisation 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
Enterprise Databases
Monash University 2004 16
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?
Enterprise Databases
Monash University 2004 17
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
Internet, Intranet and Extranet Databases
Monash University 2004 18
Need for database support, universal data accessInternet provides easy connection across multiple platformsBrowser-based applications utilise standard interface – lower development costsWeb-enabled databases allow users to ask unique and specific questions and receive answers based on current informationOnline shopping, airline ticket booking, auctionsThese are mostly BC (business-to-consumer)
Internet, Intranet and Extranet Databases
Monash University 2004 19
Businesses also deal with other businesses BBTraditionally they used electronic data interchange (EDI) as a means to trade informationExtranets 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 informationFosters relationships via more efficient exchangesOften gives access to part of company intranet
Internet, Intranet and Extranet Databases
Monash University 2004 20
Businesses often use internet technology to create internal private networks – intranetsAllow exchange and management of information within an organisation– HR, financial, programs, training, news…
Only internal access to data is allowedCan be used to connect to internetRequires additional technology to restrict external access
Internet, Intranet and Extranet Databases
Monash University 2004 21
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
Internet, Intranet and Extranet Databases
Monash University 2004 22
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
Types of Database Users
Monash University 2004 23
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, knowledge-based
systems (KBS), expert systems, complex data type storage systems, environment-modelling systems
Types of Database Users
Monash University 2004 24
ReferencesElmasri, 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_59329322.
Silberschatz, A., Korth, H.F. and Sudarshan, S., (2002), Database System Concepts, (4th edn.), McGraw-Hill Companies Inc., Boston, Mass., USA.
Recommended