What is the difference between a computed column and a manual one?
A computed column is worked out from the instrument's daily bars, for every day, automatically. A manual column is one you type into.
On the Data tab, computed columns are marked with a small ·c after their name.
A computed column is defined by a rule rather than a value. Close quartile is "which quarter of its own range did this session close in" — the app has the high, the low and the close, so it can answer that for every day the dataset covers, including the five years before you created it. That backfill is what makes the whole page work: a study needs hundreds of observations to say anything, and nobody is going to type in hundreds of days by hand.
A manual column is anything the bars do not contain. Your read on the day. A note. A link to the chart. The value-area levels out of another platform. The app leaves these blank and waits for you.
Two consequences worth knowing:
- You can overrule a computed cell. Type into one on the Data tab and your value wins from then on, and the cell gets a small amber dot to say so. Refreshing the derived columns will not overwrite it.
- Computed columns need an instrument. Creating a daily log with computed columns and no ticker is refused, because there would be nothing to compute them from.