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40 Cards in this Set
- Front
- Back
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What are some implications of Information Collection? |
Information takes many forms Will require different methods to manage depending on type of data Not all data is necessary |
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What are the four things to consider when collecting data? |
1. Consistency: Are examples treated the same way? 2. Efficiency: In storing and retrieving 3. Accuracy: Does the collected data/information correctly reflect the details of the object or situation inquestion? 4. Metadata and Structure |
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What is Metadata? |
Data about the data Describes the nature of the data Helps for consistent information processing |
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What is Data Modelling? (Structure) |
Enables consistent storage and retrieval of collected information Bridge between “real-world” and processing requirements Helps to understand the nature of information Used to inform the database design process |
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What are entity relationship diagrams (ERD's)? |
Simple analysis diagrams used for data-modelling that also show specific associations (relationships) between different entities of a business. |
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What is an entity? |
An entity is a thing or object of significance, whether real or imagined,about which information needs to be known or held. |
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What are attributes? |
Describe an individual characteristic ofan entity May also identify a unique instance of anentity Hold a single value of some well-definedtype |
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What are relationships in respect to ERD's? |
They: 1. Reflect real-world associations between things (entities). 2. Identify the direction and size of interactions between entities |
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What is an unique identifier within an entity? |
They are attributes that enable entity instances to be distinguished. E.g. The Member ID of a member entity. Each entity normally only has one unique identifier. |
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What are the three types of relationship cardinality? |
1:1 (One to One) 1:M (One to Many) M:N (Many to Many) |
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What is relationship participation in an ERD? |
Denotes whether or not instances of entity A must be related to instances of entity B in order to exist Identified by: "I" for Must (Insist) "O" for May (Optional) |
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What is an associative entity? |
An entity used to split a M:N relationship into two 1:M relationships. This is done by adding an entity that associates with both entities in the M:N relationship, and putting it in the middle. |
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What is forms analysis? |
Analysing source documents to determine information structure Eases production of ERD Enlightens us as to nature of underlying information |
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Are ERD's used by computers or humans? |
Humans. Humans use ERD's to inform the process of building databases |
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What is a database? |
A collection of persistent data that is used by the application systems of some given enterprise. |
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What are the four basic database operations? |
1. Create data 2. Retrieve information 3. Update data 4. Delete data Can be remembered as C.R.U.D |
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What does a Database Management System do? |
Manages: Creation of databases Adding and changing data Retrieval of information Who has access to what data and when Concurrent access to databases Data backups and recovery |
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A DBMS helps ensure that information is... |
1. Accurate 2. Complete 3. Correct 4. Current 5. Relevant 6. Accessible |
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What are five different types of databases? |
1. Flat (e.g., Excel spreadsheet) 2. Hierarchical 3. Object-oriented 4. Relational 5. NoSQL |
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What is the relationship model of data? |
Simple, logical structure based upon relations (tables), tuples (rows) and attributes (columns). High correlation to ERD's, but relation does not equal relationship. |
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What are tables and what do they do in the relationship model of data? |
Correspond to an ERD entity Collective storage of rows of same type: Can be “joined” with rows from other tables laterto reconstruct information Each row represents a single instance |
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What are columns and what do they do in the relationship model of data? |
Correspond to the attributes of an ERD entity
Are named Have a well-defined domain or type Can have constraints imposed to ensure quality of data collection |
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What are keys and what do they do in the relationship model of data? |
Primary key — establishes unique identifier for rows in a table. (Only one per table) Foreign keys — allow row(s) in one tableto “reference” a row in another table Ensure validity of relationships Can be more than one per table Keys can overlap |
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What is an "identifying relationship"? |
A relationship that defines (part of) a unique identifier for an entity. |
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What are three ways of putting business rules in a database? |
1. Mandatory values in tables 2. Default values for columns 3. Validation rules |
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What is a query in a database? |
The process of retrieving information from a database. |
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What is SQL? |
It stands for Structured Query Language. It is the standardised language for controlling and interacting with databases. |
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What are Aggregation Queries used for? |
They are used to produce summary information from database records Example — finding the total sales by product in Jim Bunny’s |
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Why is there a need for the Systems Development Life Cycle (SDLC)? |
Information Systems are often critical to the success of an organisation. But they are often very expensive and are a long term investment. Stems from a need for a controlled, systematic approachto their development. |
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What is the purpose of SDLC? |
Helps to identify business’ needs and information system requirements
Helps to identify and stick to a required budget Helps to identify problems early |
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What are the seven phases of SDLC? |
1. Planning 2. Analysis 3. Design 4. Development 5. Testing 6. Implementation 7. Maintenance |
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What happens during Phase One of the SDLC? |
Planning Develop the overall plan for development Main activities: 1. Define the system 2. Set the project scope 3. Develop the project plan |
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What happens during Phase Two of the SDLC? |
Analysis End-users and analysts work together toestablish the system requirements Main activities: Gathering business requirements Prioritise the requirements Early identification (and fixing on)requirements reduces overall costs |
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What happens during Phase Three of the SDLC? |
Design Build of “blueprint” of how the systemwill work Main activities: 1. Design technical architecture 2. Design system model(e.g. ERDs, UI prototypes) End-user participation lowduring this phase |
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What happens during Phase Four of the SDLC? |
Development Transform designs from designphase into a concrete system Main activities: 1. Build the architecture 2. Create database andassociated programs |
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What happens during Phase Five of SDLC? |
Testing Verify that the system meets allrequirements from phase 2 Main activities: 1. Write test conditions 2. Perform the testing: |
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What happens during Phase Six of the SDLC? |
Implementation Distribute information system to usersfor everyday use. Main activities: 1. Write user documentation 2. Provide training for the system users |
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What are the three different installation types? |
1. Direct Installation: Terminate old system and start new system straight away. 2. Parallel Installation: Have the two systems running side by side and then terminate the old one at a later date 3. Phased Installation: Phase in the new system by slowly replacing parts of the old system. Testing each part of the new system in parallel with the old system. |
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What happens during Phase Seven of the SDLC? |
Maintenance Monitor and support system to ensure itcontinues to meet business goals Main activities: 1. Build a help desk to support users 2. Provide an environment to supportsystem changes Ongoing Most expensive part of SDLC! |
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What are some examples of SDLC Participants and Stakeholders? |
-End-Users -Analysts -Developers -Project managers -Support personnel -Bankrollers |
