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.