- Hasura – Mutations
Writing through the API. `insert`, `update`, `delete`, their `_one` variants, `returning`, upserts with `on_conflict`, and the fact that several mutations in one request run in a single transaction while several requests do not. Also the harder question this track's demo app answers with a deliberate no: which writes belong in Hasura at all, and which belong behind your own API.
- Python – f-strings and Formatting
Formatting text the modern way. f-strings, the format spec that lines up currency and columns, `=` for debugging, what changed in 3.12, and the two older styles you will still meet in real code and should not write.
- Streams
A stream lets you describe what you want done to a collection instead of writing the loop that does it. It is the single biggest change in how Java is written since Java 8, and the mental model is small: a source, some intermediate operations, and one terminal operation that makes it all run. The…
- Method References
A method reference is a lambda with the noise removed. When a lambda does nothing but call one existing method, :: lets you name that method instead of describing the call. They compile to the same thing — the method reference is not faster, and it is not a different mechanism. It is the same…
- Big O Notation
How an algorithm's cost grows as the input grows — the only performance question that survives a change of hardware. The common classes from O(1) to O(2^n), how to read a complexity off a loop, why constants are dropped, and the difference between time and space complexity.