Bulk CRUD

POWER IN NUMBERS!

Query lets you Add or Remove components (and even Despawn!) in bulk – just like an individual Entity, but for thousands at once!

Quick Reference

Method	Description
Query.Add<C>(value)	Add a component to all matched Entities
Query.Remove<C>()	Remove a component from all matched Entities
Query.Despawn()	Despawn all matched Entities
Query.Truncate(n, mode)	Reduce matched Entities to a specific count
Query.Batch()	Begin a batch for multiple structural changes

Usage Examples

Damage System

// Query for all entities with Health that also took Damage
var whoTookDamage = world.Query<Health, Damage, Identity>().Stream();

// Do something for each Entity in Query
whoTookDamage.For((in Entity entity, ref Health health, ref Damage damage) => 
{
    health.hp -= damage.amount;
    if (health.hp < 0) entity.Add<Exploding>();
});

// 👇 All damage values were accounted for! Bulk remove the values.
whoTookDamage.Remove<Damage>();

Death Explosion System

// Query for all Entities that are about to Explode (and have a Position)
var whosExplodingWhere = world.Query<Position>().Has<Exploding>().Stream();

// Do something for each Entity in Query
whosExplodingWhere.For((ref Position position) => Game.SpawnExplosion(position));

// 👇 Despawn all Entities matched by Query
whosExplodingWhere.Despawn();

Multiple Bulk Operations

var loadedGuns = world.Query()
    .Has<Gun>()
    .Not<Loaded>().Not<Cooldown>().Not<RequestProjectileSpawn>()
    .Stream();

// ⚠️ Multiple bulk operations may require batching, because
// entities wouldn't necessarily match our query after each change
// and thus "escape" before subsequent operations would be applied.
loadedGuns.Batch()
    .Add<Cooldown>(2.0f)  // for our cooldown system
    .Add<RequestProjectileSpawn>()  // for another system
    .Remove<Loaded>()
    .Submit();

Adding & Removing Components

Method	Behavior
Query.Add<C>(value)	Adds component to each Entity. Throws if Query already matches that Component.
Query.Remove<C>()	Removes component from each Entity. Throws if Query doesn't match that Component.

WHY THE EXCEPTIONS?

These safety checks prevent silent no-ops. If you're adding a component the Query already matches, either ALL entities already have it, or the query is empty. Same logic for removal.

Adding Links & Relations

Object Links and Entity Relations can also be added/removed in bulk using the same pattern:

// Add an object link to all matched entities
query.Add(Link.With(sharedTexture));

// Add a relation to all matched entities  
query.Add(Relate.To(targetEntity));

Batch Operations

Structural changes often cause Entities to no longer match the Query. Use Query.Batch() to queue multiple changes:

var batch = query.Batch()
    .Add<Tag>()
    .Add<Health>(100)
    .Remove<Invulnerable>();

batch.Submit();  // Execute all at once

BATCH LIFECYCLE

Once you Submit() a Batch, the World takes ownership. You only need to Dispose() the Batch if you decide not to submit it.

Handling Conflicts

Batch operations can encounter semantic conflicts when adding/removing components:

Conflict	Example
Add<T> conflict	Some or all Entities already have that component
Remove<T> conflict	Not every Entity has that component

Pass conflict resolution strategies to Query.Batch(AddConflict, RemoveConflict):

AddConflict Options

Option	Behavior
Disallow (default)	Throw if adding a component not explicitly excluded from query
Preserve	Keep existing values, add only where not present
Replace	Overwrite existing values, add where not present

RemoveConflict Options

Option	Behavior
Disallow (default)	Throw unless component is expressly included in Query
Allow	Skip Archetypes where component isn't present (idempotent, near-zero cost)

// Example: Replace health values on all entities, even those that already have Health
query.Batch(AddConflict.Replace, RemoveConflict.Allow)
    .Add<Health>(100)
    .Submit();