Level 3 · Underground archives of glowing tables

The Data Vaults

Databases, modeling & ORM. Playable now: read the briefing, practice in the browser, then clear the checkpoint.

The Librarian

“Ask me anything, as long as you ask in SQL.”

Ask the vault the right question

Tables and rows, SELECT / WHERE / ORDER BY, safe ? parameters instead of pasted input, and JOIN.

Briefing, about 7 minutes with quick checks · read it as a guide
Shelf Search (practice): Filter and sort the vault's items with WHERE, ORDER BY and a ? parameter.
Item Floors (practice): JOIN items with vaults to find each item's floor, and 404 for the missing ones.
Vault Ledger (checkpoint): Filter, sort, count and total a vault's items, and shut the SQL injection hole.

INSERT with parameters, GROUP BY and LEFT JOIN in one query, table rules, and transactions that are all or nothing.

Briefing, about 8 minutes with quick checks · read it as a guide
Stock Room (practice): INSERT new items with ? parameters, answer the new id, and refuse unknown vaults.
Vault Census (practice): Count and total every vault in one GROUP BY query, empty vaults included.
Vault Transfer (checkpoint): Move gold between vaults in a transaction: all or nothing, 404 and 409 when it can't.