Drop features

DROP FEATURE removes features from the registry. FeatureQL enforces dependency constraints — you cannot drop a feature that other features depend on unless you handle the dependents first.

Syntax

DROP FEATURE [IF EXISTS] <feature_name>
DROP FEATURES [IF EXISTS] <feature_name>, <feature_name>, ...
DROP FEATURES [IF EXISTS] IN <namespace>

DROP FEATURE [IF EXISTS] <feature_name>
DROP FEATURES [IF EXISTS] <feature_name>, <feature_name>, ...
DROP FEATURES [IF EXISTS] IN <namespace>

Dropping a single feature

Use DROP FEATURE IF EXISTS to safely remove a feature. The IF EXISTS clause prevents errors when the feature has already been deleted:

DROP FEATURE IF EXISTS FM.TUTORIALS.CAD.FEATURE1;

Dependency protection

FeatureQL prevents you from dropping a feature that other features depend on. If FEATURE4 depends on FEATURE2, attempting to drop FEATURE2 alone fails:

-- Fails: FEATURE4 depends on FEATURE2
DROP FEATURES IF EXISTS FM.TUTORIALS.CAD.FEATURE2, FM.TUTORIALS.CAD.FEATURE3;

The error message identifies exactly which dependents need to be handled:

ERROR: You must drop all dependant features {'FM.TUTORIALS.CAD.FEATURE4'} before dropping this feature.

Dropping multiple features

Include all features in the dependency chain and FeatureQL resolves the correct deletion order:

DROP FEATURES IF EXISTS FM.TUTORIALS.CAD.FEATURE2, FM.TUTORIALS.CAD.FEATURE3, FM.TUTORIALS.CAD.FEATURE4;

Alternatively, wrap individual drops in a transaction — FeatureQL resolves the order within the transaction boundary:

START TRANSACTION;
DROP FEATURE IF EXISTS FM.TUTORIALS.CAD.FEATURE2;
DROP FEATURE IF EXISTS FM.TUTORIALS.CAD.FEATURE3;
DROP FEATURE IF EXISTS FM.TUTORIALS.CAD.FEATURE4;
COMMIT;

Mixing DROP and CREATE in a transaction

A single transaction can combine DROP and CREATE statements. FeatureQL processes them in the right order: drops first (respecting dependency order), then creates. CREATE OR REPLACE also works within transactions to atomically swap feature definitions.

When to use each variant