Orchestration
What is a UDA?
A UDA, a user-defined aggregate, reduces many rows — for example the frames of one clip — into a summary with logic you write.
Updated · Part of What is a UDF?
How it works
- Group rows, often the children of one parent.
- The aggregate function folds them.
- The summary is stored or returned with the group.
What it is not
It is not AVG() on numbers, and it is not concatenating values in the application after a full download.
UDA: this, and the thing it is confused with
| This | Not this | |
|---|---|---|
| Input | Many rows | One row |
| Logic | Yours | Only built-in SQL aggregates |
| Example | Frames of one swing | The mean of a float column |
Where Pixeltable fits
Pixeltable UDAs run over groups such as the frames of one video, and the result can feed another column.
Questions
How does UDA work?
Group rows, often the children of one parent. The aggregate function folds them. The summary is stored or returned with the group.
What is UDA often confused with?
It is not AVG() on numbers, and it is not concatenating values in the application after a full download.
Next step
Install the Pixeltable skill, or sign up for Cloud and run the same file on a hosted database.