Key term
Eduqas A-Level Computer Science A500QS
Data Structures: Arrays, Records and Hash Tables
Stacks, Queues, Linked Lists and Trees
Boolean Logic and Simplification
Algorithms, Pseudo-Code and Programming Constructs
Variables, Scope, Parameters and Identifiers
Recursion and Modular Programming
Sorting Algorithms
Searching and Shortest-Path Algorithms
Big O Notation and Algorithm Efficiency
Validation, Verification and Testing
Data Compression
Programming Paradigms and Computer Languages
Topic overviewProgramming paradigms and where each is usedProcedural programmingEvent-driven and visual programmingMark-up languagesObject-oriented programming: objects, classes and methodsAmbiguity in natural language and the standardisation of languagesBackus-Naur form and syntax diagramsHigh-level and low-level languages, and choosing one
Systems Analysis, Maintenance and Documentation
Topic overviewWaterfall, Agile and approaches to systems developmentThe feasibility study, budgets and time scalesMethods of investigationAbstraction, decomposition and data flow diagramsSelecting suitable hardware and softwareAcceptance testing and methods of changeoverPerfective, adaptive and corrective maintenanceBackup and recovery proceduresUser and maintenance documentation
System Design and Human-Computer Interaction
Software Engineering Tools and Translators
Topic overviewSoftware tools for the software engineering processSoftware packages in analysis, specification, design and testingIntegrated development environmentsDebugging toolsProgram version managementCompilers, interpreters and assemblersThe stages of compilationTranslation errors and execution errors
Computing, Society and the Law
Computer Architecture, the Processor and Assembly Language
Topic overviewHardware elements and how they are connectedVon Neumann architecture and the stored program conceptThe processor: control unit, ALU and registersTypes of memory: RAM, ROM and virtual memoryCache memory and locality of referenceThe fetch-execute cycle and its registersParallel processing and the limits to parallelisationAssembly language and executing a program
Input, Output and Secondary Storage
Topic overviewInput devices and how data is capturedOutput devices and how results are presentedChoosing input and output devices for a situationVoice input, dictation and voice print recognitionMagnetic, optical and solid state storageComparing secondary storage for a purposeDisc organisation, fragmentation and defragmentation
Networks, Protocols and the Internet
Topic overviewNetworks, LANs and WANsNetwork topologies and connection hardwareNetworking standards and the layered modelIP addressing, TCP and UDPApplication protocols: HTTP, FTP, SMTP, IMAP and DHCPHandshaking and establishing a connectionWireless hardware and wireless technologiesThe internet and connected mobile devices
Data Transmission and Network Performance
Topic overviewSerial and parallel transmissionSimplex, half duplex and full duplexMultiplexing and sharing a channelCircuit, message and packet switchingPackets, headers and packet contentsNetwork collisions and collision detectionRouting traffic on a networkCalculating transfer rates and lowest cost routes
Number Systems and Binary Arithmetic
Data Types, Characters and Floating Point
Topic overviewPrimitive data typesStorage requirements for each data typeASCII and standardised character setsUnicode and multilingual encodingFloating point form: mantissa and exponentConverting between real numbers and floating pointInteger and floating point comparedTruncation, rounding and accuracy
Files, Records and File Organisation
Topic overviewThe purpose of files in data processingFiles, records and fieldsFixed and variable length fields and recordsMaster files and transaction filesSerial and sequential file accessIndexed sequential access and multi-level indexesDirect access and hashing algorithmsOverflow handling and file reorganisationFile security, backups, generations and archiving
Databases, Normalisation and Entity Modelling
SQL, Big Data and Distributed Systems
Topic overviewQuery languages and the purpose of SQLCreating tables: CREATE TABLE, data types and keysRetrieving data with SELECT, FROM and WHEREComparison operators, IN, AND, OR and sub-queriesSorting, grouping and aggregate functionsInserting, updating, deleting and joining dataThe DBMS, the data dictionary and distributed databasesBig Data, data warehousing, data mining and predictive analytics
The Operating System and Its Modes
Topic overviewThe need for an operating system and the role of the kernelManaging peripherals, processes and memory protectionThe user interface and the layers between user and hardwareDirectory structures and file attributesUtility softwareBatch processing, real time control and real time transaction systemsTypes of operating system: single-user, multi-user, multi-tasking and multi-programmingDesigning an interface for different users and environments
Interrupts, Memory Management and Scheduling
Topic overviewWhat causes an interruptInterrupt handling and the interrupt service routineInterrupt priorities and how they are allocatedPartitioning main memoryMethods of data transfer between processor and devicesBuffers and double bufferingHigh level scheduling, processor and device allocationProcess states, time-slicing, polling and threading
Types of Software System
Data Security, Cryptography and Attack
Topic overviewOnline updating and the integrity of shared filesDangers of holding personal dataClerical procedures, access levels, passwords and write protectionCryptography: its purpose, and symmetric and asymmetric keysHashing, digital signatures and certificatesCaesar and Vernam ciphers and comparing cipher strengthBiometric technologies and their limitationsThreats, damage and contingency planningMalicious software, hacking and penetration testing
SQL, Big Data and Distributed Systems
- 8 subtopics
- 24 things to know
- Component 2
What SQL, Big Data and Distributed Systems covers
SQL, Big Data and Distributed Systems is examined in Component 2, Computer Architecture, Data, Communication and Applications. It covers query languages and the purpose of SQL, creating tables: CREATE TABLE, data types and keys, retrieving data with SELECT, FROM and WHERE, comparison operators, IN, AND, OR and sub-queries, sorting, grouping and aggregate functions, inserting, updating, deleting and joining data, the DBMS, the data dictionary and distributed databases and big Data, data warehousing, data mining and predictive analytics.
Where it is assessed
Component 2
Computer Architecture, Data, Communication and Applications.
Check the Eduqas specification ↗The 8 subtopics
Each one has its own page.
- Query languages and the purpose of SQLQuery language, why SQL is described as a declarative language and two broad kinds of task SQL commands perform.Open →
- Creating tables: CREATE TABLE, data types and keysWriting the statement that builds a table — column names and their data types, the PRIMARY KEY clause and the NOT NULL constraint.Open →
- Retrieving data with SELECT, FROM and WHEREThe three clauses of a retrieval query, what each supplies, and writing queries against a stated table to return particular columns and particular rows.Open →
- Comparison operators, IN, AND, OR and sub-queriesSix comparison operators used in an SQL WHERE clause, difference between < and <= in a WHERE clause and term sub-query.Open →
- Sorting, grouping and aggregate functionsORDER BY, GROUP BY and HAVING, the aggregate functions that summarise a column, and where each clause sits in the order of a statement.Open →
- Inserting, updating, deleting and joining dataDanger of an UPDATE statement written with no WHERE clause and term join in SQL.Open →
- The DBMS, the data dictionary and distributed databasesDatabase management system, data dictionary and distributed system.Open →
- Big Data, data warehousing, data mining and predictive analyticsBig Data, data warehouse and data mining.Open →
What you need to know
Answer each one before you reveal it.
Your recallNot started
Key term
What is a data dictionary, and what does it record?
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What is a query language?
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A school needs a table called Pupil with PupilID as a whole number and Surname as twenty characters. Write the SQL.
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State the three clauses of a basic SQL retrieval query and what each supplies.
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List the six comparison operators used in an SQL WHERE clause.
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What does the ORDER BY clause do?
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Pupil holds PupilID, Surname and Year in that order. Write SQL to add pupil 214, surname Owen, in year 12.
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What is meant by Big Data?
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Give two reasons a database is queried through a query language rather than through general-purpose program code.
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What is the purpose of the PRIMARY KEY clause in a CREATE TABLE statement?
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A table Book holds Title, Author and Price. Write SQL to list every title.
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A table Staff holds Salary. Write SQL to list all columns for staff earning more than 30000.
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Book holds Title and Price. Write SQL to list titles and prices from cheapest to dearest.
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Why is it safer to name the columns in an INSERT INTO statement?
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Name the three characteristics commonly used to describe Big Data.
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What does SQL stand for?
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What does the NOT NULL constraint do?
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What does SELECT * FROM Book return?
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What is the difference between < and <= in a WHERE clause?
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Book holds Title and YearPub. Write SQL to list titles with the newest book first.
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Pupil holds PupilID, Surname and Year. Write SQL that inserts only identifier 300 and surname Rees by naming the columns.
Key term
What is a database management system?
Key term
Give two sources that generate Big Data.
Take SQL, Big Data and Distributed Systems further
The same content, four other ways.
Commonly confused
Pairs that lose marks when they are blurred together.
ORDER BY vs GROUP BY
ORDER BY: sorting rows without removing any of them. GROUP BY: combining rows so only one is returned for each distinct value.
WHERE vs HAVING
WHERE: testing individual rows before grouping. HAVING: testing the groups after they are formed.
DELETE vs DROP
DELETE: removing rows and keeping the table. DROP: removing the table definition itself.
Questions from this topic
Each one with the model answer underneath.
- 1
What is a query language?
Model answer
A query language is a special-purpose language for retrieving and changing the data held in a database. The user states what is wanted rather than how to find it.
- 2
Give two reasons a database is queried through a query language rather than through general-purpose program code.
Model answer
A query language lets a user ask for data without writing any file-handling code. The same query also runs on any database system that supports the standard.
- 3
What does SQL stand for?
Model answer
SQL stands for Structured Query Language.
- 4
Explain why SQL is described as a declarative language.
Model answer
SQL states the result required and leaves the database system to decide how to obtain it. The programmer never codes the search algorithm.
- 5
Name the two broad kinds of task SQL commands perform.
Model answer
SQL commands define the structure of tables. SQL commands also manipulate the rows of data held inside those tables.
- 6
What is meant by a data definition command in SQL?
Model answer
A data definition command creates or alters the structure of a database object. CREATE TABLE is the clearest example.
What is inside Levo
Six ways to work the same material.
SQL, Big Data and Distributed Systems revision questions
- What does SQL, Big Data and Distributed Systems cover in Eduqas A-Level Computer Science?
- 8 subtopics: query languages and the purpose of sql, creating tables: create table, data types and keys, retrieving data with select, from and where, comparison operators, in, and, or and sub-queries, sorting, grouping and aggregate functions, inserting, updating, deleting and joining data, the dbms, the data dictionary and distributed databases and big data, data warehousing, data mining and predictive analytics. Each one has its own page with questions and model answers.
- How is SQL, Big Data and Distributed Systems organised?
- By the Eduqas A500QS specification, subtopic by subtopic, so it matches the order you are taught it in.
Every question in SQL, Big Data and Distributed Systems, on a schedule.
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