Chapter 7 Flashcards
What’s the first level of the Three-Level Database Model?
Level 1:
External, conceptual or local level
- Various “user views” of corporate data
- Each application program has own view
What is the second level of the Three-Level Database model?
Level 2:
Logical or enterprise data level
- “Technical” (human) view of all corporate data
- Controlled by database administration
What is the third level of the Three-Level Database model?
Level 3:
Physical or storage level
- Specifies the way data is physically stored
- For use by database administrators
What is the first level of the Four Data model?
- Hierarchical Model
- structured so that each element is subordinate to another in a district hierarchical manner
E.g. Parent-Child relationship
What is the 2nd Data Model of the Four Data models?
- Network Model
- allows each data item to have more than one parent
- relationships stated by pointers stored with the data
What is the 3rd Data Model of the Four Data models?
- Relational Model
Data stored in tables (intuitive for users)
- key unique identifiers
- “tuple-calculus” operations (commands such as select, join, match etc)
- Data normalisation (optimisation)
- not as efficient as hierarchical but more flexible
- Database technology of choice e.g. SQL MS Access
What is the 4th Data Model of the Four Data models?
4. Object-Oriented Database Model Extension of concept of data to objects - piece of data - methods that can perform work on data - attributes to describe the data - relationships between objects
Objects can be used to store any type of data
- e.g. Spreadsheet, video clip, photograph etc
- object database
Object-Oriented models retain traditional DBMS features including:
- end user tools
- high level query languages
- concurrency control
- recovery
- ability to handle huge amounts of data
Addition of to major concepts
- object management
- knowledge management
Object-Oriented models outperform relational systems for certain types of database manipulation
- scientific and engineering applications
Corporations are slow to adopt due to legacy systems
Tenets of objects have increasingly become important in world of computing
- e.g. Web services because XML modules utilise object principles
What is the role of the Data Admin?
Administers the database and software that manages them to provide accurate and timely information to users
Determine what data is being used outside of originating organisational unit boundaries
- Definition and format must be standardised
- Data dictionary used as main tool
- Data elements definition, schema, database structures,
Usernames, roles and privileges.
Give 5 point job description of a Database Administrator.
- Analyse data so that the organisation has the data that it needs and that data are managed in the most cost effective way.
- Help integrate DBMS with applications software
- Oversee and monitor DBMS development through in-house teams or outside contractors
- Monitor and administer DBMS security
- authorisation, backup, auditing recovery - Work with the CIO and system administrator to configure hardware and software for optimal deployment of DBMS.
Explain the concept of Managing information?
Once enterprises get their data into shape, that data can more easily be turned into information
Information is power
Managing information is a critical activity
- Technology = infrastructure
- Asset = information that runs on that infrastructure.
What are the Four Types of Information?
- Internal record based info
- Internal document based info
- External record based info
- External document based info
What is internal record based information?
It was the original focus of IS organisations because it is the type of information that computer applications generate and manage easily.
Typical corporate authority:
Information systems department
Information sources:
- translation processing
- organisational units
Technologies used
- DBMS
- Data dictionaries
- Enterprise data analysis techniques
What is internal document based information?
Document based information deals with ideas, thoughts and opinions
Typical corporate authority
- Administrative
- Vice President
- Word processing canter
- Records management
Information source
- Corporate
- memos, letters, reports, forms and emails
Technologies used
- word processing
- micrographics
- reprographics
- ext retrieval products
What are external record based information?
Typical corporate authority
- end users
- corporate planning
- financial analysis
- marketing
Information sources
- public database
Technologies used
- Internet based services
- public networks
- Analysis packages
What are external document based information?
Typical corporate authority
- Corporate library
Information sources
- Public literature
- News services
- Catalogs and indexes
- Subscriptions
- Purchased reports
- Internet e.g. Wikipedia