Databases as organized miniworlds; redundancy, inconsistency, and lack of integration in file systems.

The librarian software that defines, populates, protects, shares, and maintains data — plus real costs.

Relational model vocabulary: relation, tuple, attribute, domain, degree, and cardinality.

Domain, primary key, NOT NULL, entity integrity, and foreign-key referential integrity.

CREATE, ALTER, DROP versus INSERT, UPDATE, DELETE, SELECT, and common data types.

Wildcards with LIKE, ORDER BY, aggregates, GROUP BY, and HAVING.

PRIMARY KEY, NOT NULL, DEFAULT, CHECK, named constraints, and foreign keys in the blueprint.

Remodel tables with ALTER; DROP with CASCADE or RESTRICT.

How living data is added, corrected, and removed — and why WHERE matters.

The full picture: miniworld, DBMS, constraints, and SQL working together.