Databases & SQL Roadmap

From your first SELECT to schema design, indexing and transactions.

10 milestones · ~100 hours total

1. 1

   The relational model

   ~6h

   Tables, keys, relationships and why data is structured this way.

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2. 2

   SQL basics

   ~10h

   SELECT, WHERE, ORDER BY, LIMIT, INSERT, UPDATE and DELETE.

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3. 3

   Joins and subqueries

   ~12h

   INNER/LEFT/FULL joins, subqueries and set operations.

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4. 4

   Aggregation and window functions

   ~12h

   GROUP BY, HAVING, COUNT/SUM/AVG and window functions like running totals.

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5. 5

   Normalisation and schema design

   ~10h

   1NF–3NF, entity-relationship thinking and when to denormalise.

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6. 6

   Indexing and query plans

   ~12h

   B-tree indexes, covering indexes, EXPLAIN and finding slow queries.

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7. 7

   Transactions and isolation

   ~10h

   ACID, locks, deadlocks and isolation levels.

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8. 8

   NoSQL overview

   ~8h

   Document, key-value, column and graph stores; when each is a good fit.

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9. 9

   Design a real schema

   ~12h

   Model a small app (orders, library, bookings) end to end.

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10. 10

    Performance, backups and operations

    ~8h

    Connection pooling, replication, backup/restore and monitoring.

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