Key term
CCEA A-Level Software Systems Development CL4
Software and the Development Environment
Topic overviewSystems software and application softwareThe operating system and file managementSource code filesBinary, object and executable filesCompilers, interpreters and the build processXML files and structured dataUtility software and managing files on diskThe integrated development environmentObject oriented development platformsOpen source software and licensing
Defining Data: Types, Variables and Classes
Topic overviewPrimitive types and their storageReference types, objects and nullDeclaring variables, scope and lifetimeType casting and conversionArithmetic operators and expressionsRelational and logical operatorsOperator precedence and evaluation orderObjects as occurrences of a classAbstract, base and inherited classesAttributes and the properties of a classStatic variables in a classInterfaces and class reusability
Program Control Structures
Topic overviewSequence and the order of executionMethods and passing control between themSelection with IF and IF ELSENested IF and multi-way selectionThe switch statementCount-controlled repetition with FORConditional repetition with WHILE and DO WHILENested loops and tracing iterationsBreaking out of loops and avoiding infinite loopsChoosing and evaluating control structures
Objects, Classes and Data Structures
Topic overviewConstructors and creating objectsMethods, parameters and return valuesEncapsulation and access modifiersGetters, setters and validating an object's stateInheritance and the base classOverriding methods and run-time polymorphismOverloading methodsChoosing and organising data structuresStrings and string handlingStatic arrays of simple typesArrays of objects
Exception Handling and Managing Input and Output
Topic overviewWhy errors have to be trappedTypes of error and how an exception is raisedThe try and catch blockCatching more than one kind of exceptionThe finally block and releasing resourcesThrowing exceptions and writing an exception classChecked and unchecked exceptionsReading and validating input from the command lineControlling screen outputText filesBinary filesObject files and serialisation
Testing an Object Oriented Application
Topic overviewWhy an object oriented application must be testedChoosing test data: normal, boundary and erroneousWriting a test plan for a classTesting a class method by methodTesting constructors and object stateTesting inheritance and overridden methodsTesting error handling pathsDry runs and trace tablesTest harnesses, drivers and stubsRecording and interpreting test resultsEvaluating a test plan and re-testing
Graphical User Interface Objects and Events
Topic overviewGraphical user interfaces and console programsForms and their common propertiesLabels, text boxes and text areasButtons, check boxes and radio buttonsLists, combo boxes and other selection controlsProperties, methods and events of a GUI objectContainers, panels and laying out a formThe event loop and the event queueEvent handlers and registering a listenerThe event object and reading it inside a handlerButton, mouse and keyboard triggers
Multiple Forms and Linking to Files
Topic overviewWhy an application needs more than one formCreating, showing, hiding and closing a formModal and modeless formsPassing data between formsMenus, menu items and shortcutsToolbars and navigation buttonsDesigning navigation for a multi form applicationReading and writing text filesBinary files and streamsObject serialisation and object filesChoosing between text, binary and object files
Designing, Testing and Evaluating an Event Driven Application
Topic overviewStoryboards and what they showBuilding a storyboard from user requirementsPrototyping and refining a designError trapping in an event driven applicationUsing try and catch inside an event handlerValidating what a user types into a controlDesigning a test strategy for an event driven applicationTest plans and choosing test dataTesting the paths a user takes through an interfaceDocumenting and interpreting test resultsEvaluating an application against its requirementsEvaluating features, functionality and usability
Reasons for Systems Development and Systems Methodologies
Topic overviewWhy organisations initiate systems developmentAnalysis and design principles for business solutionsRoles in development and the place of the userThe purpose of a methodology and how methodologies evolvedThe waterfall modelIterative, incremental and spiral developmentRapid application developmentThe dynamic systems development methodScrumExtreme programmingPrototyping in the development processUML modelling and simple diagrams
Managing Projects
Topic overviewThe purpose of project managementProject management concepts and the project life cycleRoles and responsibilities in project managementResources needed to develop a projectEstimating effort, duration and costGantt charts and the scheduleMilestones and checkpointsNetwork diagrams and PERTFinding the critical pathFloat and how it is usedMonitoring and controlling progressManaging risk and change
Testing Strategies
Topic overviewWhy testing matters throughout the development cycleTesting at the design stageProgram and unit testingIntegration testingSystem testingWhite box testingBlack box testingNormal, boundary and erroneous test dataUser acceptance, alpha and beta testingThe personnel involved in testingWhat a test plan containsBuilding a test plan for a scenario
Database Concepts and Entity Relationship Modelling
Topic overviewWhat a database is and why one is usedDatabase terminology: fields, records and keysThe relational modelThe hierarchical modelThe network modelEntities and attributes in an ER modelRelationships and their degreeBuilding an ER model for a problemFrom ER model to a working designComparing the three database models
Normalisation and Structured Query Language
Topic overviewWhy data is normalisedUn-normalised data and repeating groupsFirst normal formSecond normal formThird normal formWorking a full normalisation throughThe advantages and limits of normalisationThe principles of SQLSQL commands for defining and changing dataSQL statements for retrieving dataJoining tables and grouping results
Project Management and the Systems Approach in Practice
Topic overviewBreaking a development into tasks and deliverablesEstimating durations, effort and dependenciesDocumenting the plan as a Gantt chartWorking out the critical path and floatMilestones, reviews and user sign-off pointsPlanning people, resources and skillsBuilding a plan capable of reflecting changeRecording progress against the planUpdating the plan to reflect slippageRecording change requests and versions of the planEvaluating different approaches to a business problemSelecting and justifying a specific approach
Defining Requirements and Documenting the Design
Topic overviewEliciting requirements from the userWriting functional requirementsWriting non-functional requirementsSpecifying the software and hardware the solution needsProducing and agreeing the user requirements specificationDesigning the data model and the tablesDesigning the inputs, the screens and the navigationDesigning the outputs and the reportsDocumenting the processes and the logic of the solutionTesting the design against the desired user outcomesPresenting the design and the solution using appropriate media
Building a Desktop Solution with a Database
Topic overviewApplying relational techniques to a real solutionChoosing the database and the development toolConnecting the application to the databaseData adaptorsData setsData commands and parameterised queriesBinding the database to the interfaceMultiple forms and navigationSaving changes and protecting the dataTesting and documenting the built solution
Testing and Evaluating the Solution
Topic overviewPlanning the testing of the finished solutionChoosing test data: normal, boundary and erroneousTesting validation and error handlingTesting the database and its queriesTesting the user interface and the navigationTesting the whole solution and testing with the userDocumenting test outcomes as evidenceDiagnosing failures and retestingEvaluating the test proceduresEvaluating the solution against the user requirementsEvaluating delivery against the project planEvaluating your own performance on the development
Database Concepts and Entity Relationship Modelling
- 10 subtopics
- 30 things to know
- A2 Unit 1
What Database Concepts and Entity Relationship Modelling covers
Database Concepts and Entity Relationship Modelling is examined in Unit A2 1, Systems Approaches and Database Concepts — a written examination on a pre-release case study. It covers what a database is and why one is used, database terminology: fields, records and keys, the relational model, the hierarchical model, the network model, entities and attributes in an ER model, relationships and their degree, building an ER model for a problem, from ER model to a working design and comparing the three database models.
Where it is assessed
A2 Unit 1
Systems Approaches and Database Concepts, examined on a pre-release case study.
Check the CCEA specification ↗The 10 subtopics
Each one has its own page.
- What a database is and why one is usedDatabase management system, data redundancy and data inconsistency.Open →
- Database terminology: fields, records and keysPrimary key, composite key and foreign key.Open →
- The relational modelRelational model, atomicity of a field value and relational database management system.Open →
- The hierarchical modelHierarchical database model, relationship does the hierarchical model represent naturally and data that suits a hierarchical structure.Open →
- The network modelNetwork database model, set in the network model and two advantages of the network model over the hierarchical model.Open →
- Entities and attributes in an ER modelEntity-relationship model, entity occurrence and key attribute.Open →
- Relationships and their degreeRelationship in an ER model, three degrees of relationship and one-to-one relationship.Open →
- Building an ER model for a problemIdentifying entities and attributes from a description, choosing a key for each, stating the degree and optionality of every relationship, resolving a many-to-many with a link entity, and worked models for a library, a driving school and a cinema.Open →
- From ER model to a working designDifference between a logical and a physical data model, default value and documented about each table in a physical design.Open →
- Comparing the three database modelsHow each stores an association, which relationships each can represent directly, which copes with an unanticipated question, and which suits an organisation chart, a stock system or an XML document.Open →
What you need to know
Answer each one before you reveal it.
Your recallNot started
Key term
What is a schema?
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How does a database control who may see what?
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What is a composite key?
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What is a surrogate key, and why is one often used?
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What is a view?
Numbers
What is the relational model?
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How are two tables linked in the relational model?
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Why does the order of rows in a relational table not matter?
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What is the hierarchical database model?
Evaluation
State two advantages of the hierarchical model.
Evaluation
State three disadvantages of the hierarchical model.
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How is a many-to-many relationship handled in the network model?
Evaluation
State two disadvantages of the network model.
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What does it mean to say the relational, hierarchical and network models can all hold the same data?
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What is an entity occurrence?
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What is a one-to-one relationship?
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What is a one-to-many relationship?
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Give an example of each of the three degrees drawn from a school.
Process
What are the steps in producing an ER model from a description of a problem?
Key term
Produce the ER model for a library that lends copies of books to members.
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Produce the ER model for a driving school recording lessons.
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What is the difference between a logical and a physical data model?
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What is the effect of choosing a column too small?
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Summarise how the relational, hierarchical and network models each store the association between records
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Which relationships can the relational, hierarchical and network models each represent directly?
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Compare the relational, hierarchical and network models for redundancy
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What is an entity-relationship model?
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What is an entity?
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What decisions are taken when a logical model becomes a physical design?
Take Database Concepts and Entity Relationship Modelling further
The same content, four other ways.
Commonly confused
Pairs that lose marks when they are blurred together.
Weak entity vs Link entity
Weak entity: a thing that cannot be identified without another it depends on. Link entity: a thing created to break an association each of whose sides relates to many of the other.
Derived attribute vs Stored attribute
Derived attribute: a property calculated from others whenever it is needed. Stored attribute: a property written down, which then has to be maintained.
Questions from this topic
Each one with the model answer underneath.
- 1
What is a database?
Model answer
A database is an organised, persistent collection of related data held so that more than one application can use it, with the structure of the data defined separately from the programs that read and write it.
- 2
What is a database management system?
Model answer
A database management system is the software that creates and maintains the structure of a database, enforces its rules, controls who may see and change what, and processes queries and updates on behalf of applications.
- 3
Why is storing data in application files a poor arrangement?
Model answer
Each application defines its own file layout, so the same fact is stored separately by each of them. Storage is wasted, an update applied to one file and not another leaves them contradicting each other, and no application can answer a question that spans two of the files.
- 4
What is data redundancy?
Model answer
Data redundancy is the storage of the same item of data in more than one place. Redundancy wastes space and, more importantly, creates the opportunity for the copies to disagree.
- 5
What is data inconsistency?
Model answer
Data inconsistency is the state in which two stored copies of the same fact disagree, because one was updated and the other was not. Redundancy is the cause and inconsistency is the consequence.
- 6
What is meant by data integrity?
Model answer
Data integrity is the accuracy and internal consistency of the stored data over its whole life, maintained by validation on entry, by rules linking one table to another, and by controls that prevent unauthorised or partial change.
What is inside Levo
Six ways to work the same material.
Database Concepts and Entity Relationship Modelling revision questions
- What does Database Concepts and Entity Relationship Modelling cover in CCEA A-Level Software Systems Development?
- 10 subtopics: what a database is and why one is used, database terminology: fields, records and keys, the relational model, the hierarchical model, the network model, entities and attributes in an er model, relationships and their degree, building an er model for a problem, from er model to a working design and comparing the three database models. Each one has its own page with questions and model answers.
- How is Database Concepts and Entity Relationship Modelling organised?
- By the CCEA CL4 specification, subtopic by subtopic, so it matches the order you are taught it in.
Every question in Database Concepts and Entity Relationship Modelling, on a schedule.
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