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Terminology

Glossary of terms used in Datalog UI

These terms have a a meaning outside of Datalog UI, but sometimes they have more then one meaning. This pages defines exactly what we mean by the words we use.

Table

A data structure that stores rows of Datums. This is equivalent to a SQL table.

Datum

A piece of data that lives as a row in a table. I.e. an object {foo: 1, bar: 2} in some Table with schema {foo: NumberType, bar: NumberType}.

Materialized Table

A table that is created as the result of a Query. You can't assert/retract datums to it. This Wikipedia entry applies.

Table View

A Table View is one of the core abstractions in DatalogUI. It's how you read data from a Table or Materialized Table. It exposes the methods recentData which returns data that is new since the last time you called recentData, and readAllData which reads all the data in the backing Table. If you ignore the differential part of Datalog UI, you can think of a Table View as providing you access to all the results of a query or rows in a Table. If you want to take advantage of the differential part of Datalog UI you can use recentData to give you only the changes since the last time you asked for data.

Query

A Query is the pure function that you pass into datalog.query. This function should be free of side effects. The function itself is run to understand the query declaration, but it is not run every time the query is run.