DROP ENTITY

Commands › Model entities · Admins only, through sercha_define or a tenant file

Removes an entity. A bare name is a model entity; a name of two parts, <ontology>.<Name>, is an extracted entity of an ontology. The two are handled differently.

Syntax

DROP ENTITY [ IF EXISTS ] <Name>

DROP ENTITY [ IF EXISTS ] <ontology>.<Name> [ CASCADE | RESTRICT ]
DROP TABLE  [ IF EXISTS ] <ontology>.<Name> [ CASCADE | RESTRICT ]

Parameters

Parameter	Description
<Name>	A model entity, made with CREATE ENTITY.
<ontology>.<Name>	An extracted entity, made with CREATE ENTITY (extracted). DROP TABLE is the same statement.
IF EXISTS	Succeed with a message when there is no such entity.
RESTRICT	The default for an extracted entity: refuse while an edge touches it, naming the children CASCADE would also remove.
CASCADE	Drop an extracted entity and every entity UNDER it, in one statement. A child that also sits under a parent outside the dropped set survives.

Usage notes

A model entity:

• Is refused while another entity is OF it, or a relation has it at either end. Drop those first: the model never names a missing entity.
• Takes its records with it: the view or materialized view under its name, and for an IDENTITY BY entity also <name>_members and the identity tables.
• Takes no CASCADE or RESTRICT.

An extracted entity:

• Is refused while it is the pack entity of a structure that still exists; DROP STRUCTURE removes it.
• Without CASCADE, is refused while any edge touches it.

Examples

A model entity, after the relations that use it:

DROP RELATION IF EXISTS placed;
DROP ENTITY IF EXISTS Order;

result
relation placed dropped
entity Order dropped

An extracted entity and the entities under it:

DROP ENTITY finance.Invoice CASCADE

Not supported

Refused	Write instead
CASCADE on a model entity	Drop what is OF it and the relations that use it first
DROP TABLE with a bare name	DROP ENTITY <Name>

-- Refused by the engine
DROP ENTITY Order CASCADE

-- Refused by the engine
DROP TABLE Order

See also

CREATE ENTITY · CREATE ENTITY (extraction) · DROP RELATION · DROP STRUCTURE · SHOW MODEL