Watch the database react
Short lessons on a real Postgres running in your browser. You predict, break and write; the constraints answer.
Level 0
Foundations
What a relational database is, and your first tables.
0 of 5 done
Master before moving on
- Tables, rows and columns
- CREATE TABLE
- Types
- Free10 stepsTables, rows and columnsWhat a relational database keeps, and the first rule it keeps for you: every row has the same columns, and every value fits its column.
- Free11 stepsCREATE TABLE, from nothingWrite a table from a blank page, read the errors Postgres gives when a piece is missing, and change a table that already holds rows.
- Free12 stepsTypes that tell the truthMoney that does not add up, two cities that happen in the wrong order, and an id that runs out: the type is the first constraint on a column.
- Free2 stepsLevel 0 boss: the library loans tableOne table from one paragraph of requirements: every column with the type that tells the truth, and the defaults a new row needs.
- Free9 stepsUnder the hood: how a row is storedPages of 8 kB, the address every row has, and why an UPDATE writes a new row instead of changing the old one: the storage under every table.