Database Foundations

Lessons in This Module

1. Lesson 1

   What a Database Does

   A database stores and retrieves structured product information while enforcing selected rules about its shape, identity, and relationships. Learn the founder decision, practical evidence, and warning signs that matter.

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2. Lesson 2

   Records, Tables, Documents, and Relationships

   Records represent individual facts, tables or collections group them, documents package related fields, and relationships connect business entities. Learn the founder decision, practical evidence, and warning signs that matter.

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3. Lesson 3

   SQL and NoSQL

   SQL databases emphasise structured relations and declarative queries; NoSQL describes several models designed for different flexibility or scale patterns. Learn the founder decision, practical evidence, and warning signs that matter.

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4. Lesson 4

   PostgreSQL, MySQL, and MongoDB

   PostgreSQL and MySQL are relational databases, while MongoDB stores document-shaped records with different modelling and consistency tradeoffs. Learn the founder decision, practical evidence, and warning signs that matter.

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5. Lesson 5

   Designing a Basic Data Model

   A data model names the product's entities, attributes, identities, relationships, constraints, and lifecycle. Learn the founder decision, practical evidence, and warning signs that matter.

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6. Lesson 6

   Validation and Data Integrity

   Validation rejects unacceptable input, while data integrity means stored information remains accurate, consistent, and related according to product rules. Learn the founder decision, practical evidence, and warning signs that matter.

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7. Lesson 7

   Migrations and Schema Changes

   A migration is a controlled, repeatable change to database structure or stored data as the product evolves. Learn the founder decision, practical evidence, and warning signs that matter.

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8. Lesson 8

   Backups and Recovery

   A backup is a recoverable copy of data; recovery is the tested process that restores usable service from it. Learn the founder decision, practical evidence, and warning signs that matter.

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9. Lesson 9

   Data Export, Retention, and Deletion

   Export, retention, and deletion policies govern how data leaves the system, how long it remains, and when copies are removed. Learn the founder decision, practical evidence, and warning signs that matter.

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10. Lesson 10

    Multi-Tenant Data

    Multi-tenant data architecture stores information for multiple customers while preserving explicit ownership and isolation boundaries. Learn the founder decision, practical evidence, and warning signs that matter.

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11. Lesson 11

    Recognising Weak Database Design

    Weak database design is visible through ambiguous ownership, duplicated truth, missing constraints, destructive changes, and queries that cannot express product rules safely. Learn the founder decision, practical evidence, and warning signs that matter.

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