Eduqas A500QS 2.5: Databases and distributed systems
The free BugBot lessons that teach this point, a robot to try it on, and the past-paper questions that test it.
Lessons that teach it
- A11.1 Data models and entity relationships Databases and big data
Model the data before building anything: entities, attributes, entity descriptions and the degree of each relationship, drawn as an entity… - A11.2 Relational databases and keys Databases and big data
Flat files against relational databases, and every kind of key: primary, composite, foreign and secondary, with indexes and how records… - A11.3 Normalisation to third normal form Databases and big data
Functional dependencies, update anomalies, and taking a flat score sheet through first, second and third normal form. - A11.4 SQL: defining tables and joining them Databases and big data
CREATE TABLE with types and keys, ALTER and DROP, then SELECT with INNER JOIN, wildcards, aggregates, GROUP BY and nested queries. - A11.5 SQL: changing data and referential integrity Databases and big data
INSERT, UPDATE and DELETE at A level, and how a database refuses orphan records. The robot logs its own moves. - A11.6 Transactions and ACID Databases and big data
A transaction is all or nothing: atomicity, consistency, isolation and durability, commit and rollback, and redundancy. - A11.7 Client server databases and concurrent access Databases and big data
Many clients, one database: the lost update, and the four ways to prevent it: record locks, serialisation, timestamp ordering and… - A11.9 Big data Databases and big data
Volume, velocity and variety; why one server is not enough; distributed processing with map and reduce; the fact-based model and graph… - A11.10 Project: the run database Databases and big data
Design, normalise, build and fill a database of robot runs, log live runs in transactions, report with one joined query and export the… - A12.8 Client server, REST and thin clients Networks and the web
Peer to peer and client server, websockets, CRUD and REST with JSON, and thin versus thick clients.
Try it on a robot
The task from A11.1 Data models and entity relationships, running here. Change the program and press Run.
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