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0.10 (stable)
DROP Statement

The DROP statement removes a catalog entry added previously with the CREATE command.

Examples 

-- delete the table with the name "tbl"
DROP TABLE tbl;
-- drop the view with the name "v1"; do not throw an error if the view does not exist
DROP VIEW IF EXISTS v1;

-- drop function "fn"
DROP FUNCTION fn;
-- drop index "idx"
DROP INDEX idx;
-- drop schema "sch"
DROP SCHEMA sch;
-- drop sequence "seq"
DROP SEQUENCE seq;
-- drop macro "mcr"
DROP MACRO mcr;
-- drop macro table "mt"
DROP MACRO TABLE mt;
-- drop type "typ"
DROP TYPE typ;

Syntax

Dependencies of Dropped Objects

DuckDB performs limited dependency tracking for some object types. By default or if the RESTRICT clause is provided, the entry will not be dropped if there are any other objects that depend on it. If the CASCADE clause is provided then all the objects that are dependent on the object will be dropped as well.

CREATE SCHEMA myschema;
CREATE TABLE myschema.t1 (i INTEGER);
DROP SCHEMA myschema;

Dependency Error: Cannot drop entry "myschema" because there are entries that depend on it.
Use DROP...CASCADE to drop all dependents.

The CASCADE modifier drops both myschema and myschema.t1:

CREATE SCHEMA myschema;
CREATE TABLE myschema.t1 (i INTEGER);
DROP SCHEMA myschema CASCADE;

The following dependencies are tracked and thus will raise an error if the user tries to drop the depending object without the CASCADE modifier.

Depending object type Dependandt object type
SCHEMA FUNCTION
SCHEMA INDEX
SCHEMA MACRO TABLE
SCHEMA MACRO
SCHEMA SCHEMA
SCHEMA SEQUENCE
SCHEMA TABLE
SCHEMA TYPE
SCHEMA VIEW
TABLE INDEX

Limitations

Dependencies on Views

Currently, dependencies are not tracked for views. For example, if a view is created that references a table and the table is dropped, then the view will be in an invalid state:

CREATE TABLE tbl (i INTEGER);
CREATE VIEW v AS
    SELECT i FROM tbl;
DROP TABLE tbl RESTRICT;
SELECT * FROM v;

Catalog Error: Table with name tbl does not exist!

Limitations on Reclaiming Disk Space

Running DROP TABLE should free the memory used by the table, but not always disk space. Even if disk space does not decrease, the free blocks will be marked as “free”. For example, if we have a 2 GB file and we drop a 1 GB table, the file might still be 2 GB, but it should have 1 GB of free blocks in it. To check this, use the following PRAGMA and check the number of free_blocks in the output:

PRAGMA database_size;
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Last modified: 2024-04-24