Database key terms Flashcards
Table (entity)
A table consists of one or more records, it is a structure where data is organised in rows and columns
Field (attribute)
A field contains one items of data about a person or thing. it is vertical
Record
A collection of data items related to an object or person (horizontal)
Primary key
Uniquely identifies records in a table
Foreign key
A field in one table which refers to the primary key in another table
Composite key
A composite key is one that consists of two or more fields
Data dictionary
Shows the structure of data items to be used in the database by defining the basic organization of data
Presence check
Checks data has been entered into a field
Range check
Checks that data has been entered within the upper and lower limits
Length check
Ensures the data is the correct number of characters
Type check
Ensures that the data entered is the correct type
Format check
Checks that the data matches the predetermined format
Wireframe
A diagram to show the layout of a page of a multimedia application before coding it
Form and report wireframes (what do they contain)
Logo, Field names, Headers, interactive buttons, Footer, User interaction items
Navigational structure diagram
Shows the pathway between hyperlinks and pages of a multimedia application
ERD diagram
Entity relationship diagram - Planning tool which shows the relationships between tables and data in a database
Relationship
Links two tables in a database using a field that exists in each of the tables
QBE
Query by example - Used to search and extract data from the database to find the answer to a question.
It is a kind of form which the user fills out to find the relevant data. Easier for the user to use as they don’t need to learn how to find data using SQL- Structured Query language
Logical operators
Used to analyse two values and return either a true or false result
SQL statements
Structured query language - Used to create databases and retrieve/process data within a database.
SELECT
FROM
WHERE
reports
Provides the user with a summary data relating to all records in the report. It allows query results to be shown in a user friendly way
Forms
Used to enter a new record into a table or modify an existing record and view any records already stored in the table
Macros
A set of commands which is used to perform a repetitive task automatically
Relational database
A database where all the tables are linked by various relationships. Reduces data redundancy and increases data integrity
Data redundancy
Unnecessary duplication of data in a database. The same data is present in multiple tables and can slow the database down by increasing the file size and amount of data to be processed
Data integrity
Accuracy of data stored in a database
Referential integrity
Ensures that an entry cannot be made in one table with a foreign key, if the key field does not exist in the linked table
Look up list
A list of data which can be used to provide all available values for a given data field
Input masks
Method of controlling the format of data which is being entered into a database
Cascade delete/update
Ensures that changes made in the linked table (where foreign key is entered) are also shown in the primary table
Waterfall model
Represents a sequential approach to application development
The stages need to be completed in order and the next stage cannot begin until the previous stage has been completed
Iterative development approach
Testing and making changes at different stages of development
Bugs
An error or fault which leads to errors in the execution of a program or application
Testing evidence
Documentation which illustrates the outcome of tests applied to application software, this may be in the form of annotated screenshots
Testing strategies (the table headings for the testing evidence)
Individual tests
descriptions of the area to be tested
Test number
Actual outcomes of testing
Expected outcomes of testing
Comments about the outcomes of testing
Null data
Used to test that the system can cope when NO DATA IS ENTERED
invalid data
Abnormal data which is entered and shouldn’t normally be accepted by the system
Extreme data
Data entered which lies at the boundary and should be accepted by the system
Erroneous data
Data which is the wrong data type than what should be entered, should be rejected
White box testing
Used to test code
The tester must have an idea of how the system is to be used. This approach is very effective as it can identify any errors in the early stage of system development
White box testing advantages and disadvantages
Adv: Started at an earlier stage, doesn’t need gui to be made yet to test, More thorough
Disadv: Testing can be complex as the tester is working with code, Tester needs to have a comprehensive knowledge of programming before testing to insure effectiveness
Black box testing
Examines the software functionality
The tester knows the formal inputs and expected outputs and documentation of testing forms the basis
Black box adv and disadv
Adv: Tests are completed from an end user pov, tester doesn’t need to know programming languages to test the system, tests can be completed as soon as specifications are completed
Disadv: Only a small number of input tests can be completed which leaves many paths untested, Tests can be difficult to design if there are no specifications
System testing
Tests how all parts of the system work together and is carried out on a completed system.S
system testing adv and disadv
Adv - Simulates actual system usage, Doesn’t make any system structure assumption
Disadv - Can miss logical errors, high possibility of redundant testing
Alpha testing
Early test of new or updated system software and is done by the manufacturers before the beta testing commences (done by the users).
this type of testing incorporates black box testing methods
Alpha testing adv and disadv
Adv - simulates real time behaviour, Errors are detected early on
Disadv - Developers could be dissatisfied with the results, Functionality cannot be fully tested as the system is still in development
Beta testing
Carried out using free trial versions of the application. A sample of the intended audience sample the product.
Beta testing adv and disadv
Adv - Reduces chance of the product failing, Increases customer satisfaction, collects data and tests it at the same time whilst saving time for the developers by allowing a separate audience to test it for them.
Disadv - Less control of how testing is conducted as it is completed in the real world, finding the right testers can be a problem
A/B testing
Compares two versions of a web page to test which one holds up better and is better recieved by the target audience
A/B testing adv and disadv
Adv - Ease of implementation, Ease of analysis and test design, Flexible
Disadv, Limited number of concepts, inefficient data collection
Evaluation
To improve the product being developed by identifying problems with the application. It is used to gain feedback from the end user
