information systems and databases Flashcards
what are the characteristics of an information system
- the characteristics of an information system, namely:
- the organisation of data into information: data needs to be organised before it can become meaningful information. organising may require sorting, summarising or classifying before it is stored. a data dictionary is a tool used to help organise the data
- the analysing of information to give knowledge: the information must be analysed so that people can gain knowledge from the information stored. tools used for analysing data includes tables, queries and reports
what are some of the different types of information systems
include systems used to:
- process transactions
- provide users with information about an organisation
- help decision-making
- manage information used within an organisation
what is a transaction processing system (TPS)
a transaction processing system (TPS) collects, stores, modified and retrieves the daily transactions of an organisation. examples of these systems are credit card payments, EFTPOS and ATMs. There are two types of transaction processing: batch processing and real-time processing
- batch processing collects the transaction data and processes it later
- in real-time processing, each transaction is processed immediately
what is a management information system (MIS)
Management information system (MIS).this system provides information about the performance of an organisation to the managers. this involved the production of reports on sales, inventory, payroll, orders and budgets. this measure of performance is used to motivate workers and make decisions
what is a decision support system (DSS)
a decision support system (DSS) assists people to make decisions by providing information, models and analysis tools. these systems are used in the statistical analysis of examination results, analysis of the stock market for buying and selling shares, and decisions made by a company used a what-if model in a spreadsheet to project future sales. expert systems are examples of decision support systems where a user is asked a set of questions and the answers compared to a knowledge base to obtain a possible solution. doctors use expert systems to determine the correct treatment of a particular disease by comparing signs and symptoms to the knowledge base.
what is an office automated system (OAS)
Office automated system (OAS). this system provides an effective way to complete tasks in an organisation. a range of appropriate software tools are available for the editing and production of high quality documents and to provide both internal and external communication
what is the environment in a school database that holds information on teachers, subjects, classrooms and students (talk about 6 types of environment)
- Physical: The school network; part of Department of Education and NESA; where to save documents; who has access
- Social: Needs to be used by students, teachers and administration staff
- Technological: Network access required; will it be available online via the Internet; will there be training to use the system
- Economic: What software can the school afford?
- Political: Can be influences by political parties on the education system overall but not really the specific timetable system
- Legal: Requirements for hours studied on courses; privacy laws about student data
what is the purpose of the school timetable system
- The purpose of a school timetable system is to:
- Provide accurate details to each teacher and student with regard to where and what they should be doing throughout each school day
- Enable the location of any teacher or student to be accurately determined at any time throughout each school day
- Provide flexible retrieval methods so timetable data in various forms can be provided to the school’s administration system
what data/information is used in the school timetable system
- data
- Student details such as student number, name
- Subject names
- Classroom details – number, how many students fit into room, is it meant for special subjects
- Teacher names
- Subjects that teachers can teach
- information
- The timetable for each student and teacher
- Results of a search for where to find a student or teacher
- Timetables for rooms – which rooms are available if you want to book a room
who are the participants of the school timetable system
- Office staff, teachers
- There is a team of teachers who develop the timetable using the software and student subject choices – they are the participants
- If students contribute to the system by making subject choices online, they can be considered as participants as well as users
who are the users of the school timetable system
Students, teachers, parents and the administration staff are users of a timetable system
what information technology is used in the school timetable system
- Hardware:
- File servers to store the data
- Laptops and desktop computers
- Network devices
- Screens
- Printers
- Software:
- Specific software to generate the timetable – for us it is Edval
- Also connects to overall school administration system – for us it is Sentral
- Databases are involved in both pieces of software
identify the 7 information processes in the school timetable system
- Collecting
- Student data is collected – names, numbers, year group. For the timetable system, the data is collected from the overall school administration system
- Student subject choices are collected * Teacher data is collected – names, what they can teach, preferences for classes
- Room data is collected – number of room, how many students can fit in the room, is it a science lab or art room or computer room, etc
- Organising
- Data is organised into a database
- Database schema is developed which represents the tables to be used and their relationships
- Analysing
- Creating the timetable by analysing subject choices, available teachers, etc
- Searching for student location, available rooms, etc
- Creating class lists
- Processing
- Making any changes to the timetable
- Making changes to student details
- Transmitting and receiving
- Sharing the timetable online with teachers, students and parents
- Sharing the data with Department of Education if required
- Displaying
- Viewing the timetable on screens or printing it out
- Viewing the results of searches for the location of teachers or students
outline an ISC diagram for the Roads and Traffic Authority system holding information on automobiles and holders of drivers licences
- Environment:
- NSW vehicle owners, government (NSW department of transport), police and courts.
- Purpose:
- To manage registration of all drivers and motor vehicles in NSW.
- To provide information to drivers/applicants on matters such as licensing, vehicle registration, etc. as well as statistical information to government and other authorities.
- Data/information:
- Drivers’ details (contact, payment, driving history, license information), vehicle details (registration numbers, make of car, etc.)
- Participants:
- Data entry operators, administration staff at offices, police department
- Information technology:
- Hardware: Computers, cameras, barcode scanners, networking between computers
- Software: Operating system, database software
- Information processes:
- Cover the seven processes; collecting, organising, analysing, storing and retrieving, processing, transmitting and receiving, displaying
outline an ISC diagram for a video store holding information on borrowers and videos
- Environment:
- Staff, customers around the area, suppliers, other chain stores, head office.
- Purpose:
- Allowing customers to hire videos for a period of time, keeping an accurate record of rentals and stock.
- Data/Information:
- Customer details, current loans and overdue items, rental records (in stock/on loan), rental fees, video details, barcodes, receipts
- Participants:
- Staff, head management
- Information technology:
- Hardware: Computers, barcode scanners
- Software: Operating system, database software
- Information processes:
- Cover the seven processes; collecting, organising, analysing, storing and retrieving, processing, transmitting and receiving, displaying
what are some non-computer methods for organising
- telephone books where the subscriber’s surnames are sorted alphabetically
- card based applications
- recipe cards
- dictionary - words are sorted alphabetically
- photography album, photos are organised chronologically
what are some computer based method for organising
- flat-file system
- database management system
- hypermedia
what is a flat-file system
- A single table of data stored as a single file. All rows (records) are composed of the same sequence of fields (attributes)
- Telephone books, appointment diaries and even filing cabinet
what is a database management system
- System software for creating and managing databases.
- Data is organised into tables, viewed in forms, retrieved using queries and displayed in reports
- Manipulates the data in different ways, such as sorting and searching
- Allows simultaneous management and use of several separate databases
- Allows relationships between data in different databases (relational databases)
- Data can be organised into different databases for each category and can then be linked together
- Can make flat file and relational databases
what is hypermedia
- A combination of media whose locations are linked to provide an easy way to navigate between the documents
- World Wide Web is one large hypermedia data store where web pages are linked together
- Mainly used on the Internet
- Limited data processing capabilities
- Allows documents to be cross-linked in such a way that the user can move from one document to another by clicking on a text link (hyperlink)
what are some advantages fo computer based organisation methods
- data can be easily edited without having to retype all the data
- large storage space is available on disk and data is easily retrieved when required. non-computer databases require a large storage space
- data can be searched for and retrieved quickly
- data can be presented in many formats such as tables, forms or reports
- data can be accessed by several people at the same time
- backup storage can be kept, eliminating the risk of data loss
- access to confidential data can be restricted
- sorting of data is flexible over a range of fields
- arithmetic manipulation of data is possible
- They are considerably faster to search
- the data can be easily exchanged between applications and over networks
- Vast amounts of data can be stored in relatively small amounts of space
what are some disadvantages of computer based organisation methods
- reliance on technology - consequences from technological failure
- maintenance and upkeep - cost
- digital divide
- The data can only be accessed if you have a computer and then you might also need to have the specific software installed on your computer
- Training is usually required
- The exchange of data with other computers creates problems of security and confidentiality
what are some advantages of non-computer based organisation methods
- Do not require a computer, a power supply or batteries
- May be portable, weight very little and fit inside a briefcase or bag
- No special skills or training are needed to use them
- A small amount of data can be quickly and easily retrieved and no extensive processing is needed
- No expensive hardware or software is required to be purchased
- Non-computer storage may be more secure because it can be held in locked drawers or offices and is not accessible across a network
what are some disadvantages of non-computer based organisation methods
- May be physically destroyed by fire, water damage or pests
- If they are very large they may take a long time to search for specific data
- If items are incorrectly filed they may be very difficult to find
- May require more work to display the retrieved information
- Access is usually by one method only, for example, alphabetically by surname or chronologically by date
- Usually only one person can access the data at any one time
what are some advantages and disadvantages of flat-file databases
flat-file databases are simple to create and organise, easy to use and inexpensive. however they can have a high level of data redundancy, are slower to access and may have inconsistencies in their report generation.
what are the parts of a flat-file database
- files: a collection of related records. the information is stored in the file in such a way that the computer can read information from the file or write information to the file
- records: a collection of related data items, which occur in fields
- fields, key fields
- field - a collection of related data entries. each record is subdivided into fields, where a field is a set of contiguous characters with a special meaning
- key field (or primary key) - a field which uniquely identifies a specific record
- characters
- entry - characters entered into the field
what do relational databases do
a relational database organises data used a series of related table. it can be presented in a schema (IS RELATIONAL DATABASE IS NTO NECESSARILY A SCHEMA) or table
what is a schema
an organised plan of the entire database, showing where the data is found and the logical relationships
what are the parts of a schema
- entities: the specific ‘thing’ about which data is collected and stored. separate table in the schema indicate the entities, for example, customers, salespersons, and so on
- attributes: the defined property of an entity. attributes are the same as fields in a flat-file database. for example first name, date ordered, so on
- relationships: the way in which entities are related to each other. the key field is used to link entities.
- one to one: (seldom used)each record in the first entity is related to exactly one record in the second entity. for example, each primary school teacher is assigned to one class in primary school
- one to many: (often used) each record in the first entity relates to many records in the second entity. for example, each secondary teacher is assigned to many classes in the high school
- many to many: each record in the first entity relates to many records in the second entity, and each record in the second entity is related to many records in the first entity. for example, each student studies many subjects and many students study each subject
what are the parts of a table for a relational database
a table is made for each entity (ie each table in a schema can be expanded on in a flat-file table).
- attributes: information in a column (field) of the table is the attribute of the entity and represents the field
- records: a row in the table is called a tuple of an entity and represents a record (its like the name of a person and all their information that relates to that entity)
view image in notes
what is a primary key and foreign key
primary key - a field that stores data that uniquely identifies the record
foreign key - an attribute which is the primary key for another table
what is referential integrity
Referential integrity is ensured when each foreign key always matches a related primary key. Two issues result from enforced referential integrity that need to be resolved – what to do if a primary key is updated (changed) and what to do if a primary key record is deleted when related records exist?
in a relational database, what different user view may be used and for what purpose would each view be used
data can be viewed for different purposes using a variety of formats. these include:
- table view - all the records are displayed in a table format. images are not displayed in this format. used to view inputted data
- form view - each record is displayed separately. the form is used for the input of data into a new record or displaying images that are stored in a field as well as other fields that are stored. commonly used for data input to enter, view and edit data
- report view - output of data for printing. the report can be formatted to have headers and footers a title and logos so that a hard copy can be produced. the report can include information from a query or table and is used to present data retrieved from one or more records. used as a summary format and output of data for printing.
what is a data dictionary
contains information abut how the data in each field is to be constructed. a data dictionary contains metadata, or information about data. the description helps to standardise data entry and provide documentation for the database.
what is included in a data dictionary ? expand on each
- field name: Name of each field as it appears in a database
- data type: type of data to be inputted. there are 6 types
- data format: shows how the data is to be displayed such as how the date is to be displayed (DD/MM/YYYY) or the number of decimal places in a number (nnn.nn)
- field size or width: the number of characters allowed in the field. the field size can be used to determine the storage space required for the database. if field sizes are kept to a reasonable size, the database will work more efficiently
- description: specifies the content of the field
- example: an example of data is given to illustrate possible valid content
what are the 6 different data types that can be entered into a field
- alphanumeric data or text - composed of letters of the alphabet and umbers and can also include symbols from the keyboard. it can also be referred to as text (limited number of characters, access restricted to 50) or memo (greater than 50 characters, presented in a scroll box)
- Unicode or ASCII? Unicode is an extension of the ASCII character set to include many foreign language characters and a variety of other special symbols.
- numeric data - data composed of numbers and numerically-related symbols. numeric data can be formatted to currency or a fixed number of decimal places or percentage
- boolean or logical data - composed of true/false or yes/no
- date data - often displayed as dd/mm/yy or mm/dd/yy
- time data - usually in the form hh/mm eg 11.05am
- calculation - which shows the formula used in the field
what are schematic diagrams
schematic diagrams are graphical tools that are used to describe the database and help in the development of a relational database. they identify the entities and show the relationships between them. they help to identify what data is included or excluded from an entity (different to schema)
what is normalisation? what might cause unnormalised data
Normalisation is the process of removing redundancies in the tables and fields to produce a set of tables which are flexible and easier to maintain. Normalisation does lead to more tables and relationships but the advantage of normalising a database to Third Normal Form (3NF) is that it improves data integrity and reduces the possibility of anomalies occurring in the data. Anomalies in unnormalised table structures are caused by:
- insertion – data being added may not be consistent with data already in the table relating to the same facts
- Deletion – when data is repeated only some of the data may be deleted, leaving records in the database which should not be there
- Updating – if data is repeated, the update routine might only update some of the records causing inconsistencies between records about the same facts
what are the 3 normal forms. how do
- first normal form (1NF).
- Each field stores single data items
- eliminates repeating groups (eg first last name split)
- logical input of data (eg offences split)
- second normal form (2NF)
- table must be in 1NF and every non-key attribute (field) should be dependent on the tables primary key - split into more than one entity, all attributes related to the primary key
- redundant information removed (eg date of birth and birth year)
- third normal form (3NF)
- table must be in 2NF and every non-key attribute is dependent only on the primary key of the table and is not dependent on another attribute in the table.
- if attributes do not contribute to a description of a key, remove them to a separate table
- might be meticulous in making tables (eg seperate table for address as postcode is dependent on the suburb)
what is hypermedia
hypermedia is the storage of information using a set of documents or nodes that may contain text, numbers, images, audio and video. each document or node is independent and can be retrieved electronically using hypertext.
what is hypertext
hypertext is a system where documents can be cross-linked in such a way that you can navigate from one document to the next by clicking on hyperlinks, which are electronic connections. a well-known application of hypermedia and hypertext is the world wide web. each document (or page or node) is accessed by its URL
what are nodes
- a point where links are connected
- any system or device connected to a network that can send, receive, or forward information
- in hypertext terms, some block of information - perhaps a web page, video etc
