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STUDY GUIDE · GKU 6

Information management: data modelling, databases and SQL study guide (Information Technology)

An IT department keeps the organisation's data alive: it decides what is collected and how long it is kept, models it so that the database refuses nonsense, chooses the kind of database that suits each workload, lays the tables out so that queries are fast, and then runs the database day to day — accounts and privileges, backups that actually restore, a catalogue that says what every column means, and SQL to answer questions. This unit follows that order. A help desk, with its tickets, departments and device inventory, runs through the sections so that each result can be checked by hand.

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Structured by the official ETEC subject standard for this topic: every listed topic and learning outcome, with formulas, figures and worked examples. The full sections are available to members in the app.

SKU 6.1 · Data-information concepts and data modelling

  1. Data, information and databases: collection and retention

    What data, information and databases are for in an organisation, how data is collected and what that implies, and how long it is kept, where, how it is backed up and how it is protected — including sizing a grandfather-father-son backup set and setting a retention date.

  2. Entity Relationship diagrams

    How to turn an organisation's business rules into an Entity Relationship diagram: entities, attributes and keys, relationships with their cardinality and participation, weak entities, attributes of a relationship and associative entities, and how each piece becomes tables.

  3. Relational operations and non-relational databases

    The relational operations — select, project, union, intersection, set difference and natural join — applied by hand to small relations, and how object-oriented, XML, NoSQL and NewSQL databases differ from the relational model and when each is the right choice.

  4. Normalisation, indexing and constraints in the physical design

    How normalisation to 2NF and 3NF removes update anomalies, how constraints make the database refuse bad data, and how a B+-tree index turns a full-table scan into a handful of page reads — and when an index or a little denormalisation does not pay.

SKU 6.2 · Database management and query languages

  1. Database administration and security

    What a database administrator does day to day, and how a database is secured: accounts, roles and least privilege with GRANT and REVOKE, views that hide columns, auditing, encryption, patching and safe application access.

  2. Backup and recovery

    Full, differential and incremental backups and the transaction log; which files a restore needs and in what order; how much storage each strategy uses; and how to design a strategy that meets a recovery point objective and a recovery time objective.

  3. Metadata management

    What metadata is — technical, business and operational — where the DBMS keeps it (the system catalogue and data dictionary), how to query it, and why missing or inconsistent metadata produces wrong reports.

  4. SQL: filtering, sorting and grouping

    How a SELECT is evaluated, and the clauses that filter and order data: WHERE with comparison, BETWEEN and LIKE, ORDER BY, GROUP BY with aggregates, and HAVING — with the NULL and boundary traps that decide exam answers.

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