Queries

As a key concept behind fennecs, Queries have three main purposes.

• 1. Matching & Filtering Entities
• 2. Processing Data (through Stream Views)
• 3. Bulk Create, Read, Update, Delete

Each Query is a view into a World, representing a subset of its Entities. Queries are incredibly fast and update accordingly whenever entities spawn or their component structure changes.

(expand to see world)

A World contains Entities and their Components, as well as their structure and Relations.

1. Matching & Filtering Entities

It remains associated with this specific World, and Queries can not bridge multiple Worlds. Queries use Match Expressions to define the subset of Entities they contain ("match").

2. Processing Data (through Stream Views)

The most powerful feature of Queries is that they can provide a Stream View (also known as a zip view) that can run code on all Entities in the Query; and even provide mutable references to component data (the Stream Types) to the delegate code being passed in.

3. Bulk Create, Read, Update, Delete

Queries expose methods to operate quickly and with clear intent on all the entities matched by the query - read more!

Use the method Query.Despawn() to despawn all Entities in that Query. Alternatively, use Query.Truncate(int, TruncateMode) to cut your Query down to a specific size.