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Database Basic

08 Sources/Saturngod PDFs/Database Basic.md

Database Basic

Official PDF

Actual coverage

Database concepts and MySQL setup; schemas/tables/data types; CRUD and filtering; keys and relationships; normalization through 1NF/2NF/3NF/BCNF; joins; transactions/ACID; views; indexes; partitions; Python connectivity; stored procedures/functions/triggers.

Durable knowledge

  • A schema is executable domain policy: types, nullability, uniqueness, references, and checks prevent invalid states.
  • Primary keys establish identity; foreign keys preserve relationships; composite keys express multi-column identity.
  • Normalization reduces update/insert/delete anomalies by separating facts according to dependencies.
  • Joins reconstruct related views; query shape and cardinality determine cost.
  • Transactions protect multi-step invariants through atomicity, consistency, isolation, and durability.
  • Indexes accelerate matching/order at the cost of storage and slower writes; design from real query patterns and inspect plans.
  • Stored logic can centralize behavior but also hide coupling and complicate versioning/testing.

Security rule

Always parameterize values. Never build SQL by concatenating untrusted input.

Knowledge connections