DROP TABLE

The DROP TABLE statement removes a table and all its indexes from a database.

The DROP TABLE statement performs a schema change. For more information about how online schema changes work in CockroachDB, see Online Schema Changes.

Required privileges

The user must have the DROP privilege on the specified table(s). If CASCADE is used, the user must have the privileges required to drop each dependent object as well.

Synopsis

Parameters

Parameter	Description
`IF EXISTS`	Drop the table if it exists; if it does not exist, do not return an error.
`table_name_list`	A comma-separated list of table names. To find table names, use `SHOW TABLES`.
`CASCADE`	Drop all objects (such as constraints and views) that depend on the table. `CASCADE` does not list objects it drops, so should be used cautiously.
`RESTRICT`	(Default) Do not drop the table if any objects (such as constraints and views) depend on it.

Viewing schema changes

This schema change statement is registered as a job. You can view long-running jobs with SHOW JOBS.

Examples

Setup

The following examples use MovR, a fictional vehicle-sharing application, to demonstrate CockroachDB SQL statements. For more information about the MovR example application and dataset, see MovR: A Global Vehicle-sharing App. To follow along, run cockroach demo to start a temporary, in-memory cluster with the movr dataset preloaded:

$ cockroach demo

Remove a table (no dependencies)

In this example, other objects do not depend on the table being dropped.

> SHOW TABLES FROM movr;

  schema_name |         table_name         | type  | estimated_row_count
--------------+----------------------------+-------+----------------------
  public      | promo_codes                | table |                1000
  public      | rides                      | table |                 500
  public      | user_promo_codes           | table |                   0
  public      | users                      | table |                  50
  public      | vehicle_location_histories | table |                1000
  public      | vehicles                   | table |                  15
(6 rows)

> DROP TABLE promo_codes;

DROP TABLE

> SHOW TABLES FROM movr;

  schema_name |         table_name         | type  | estimated_row_count
--------------+----------------------------+-------+----------------------
  public      | rides                      | table |                 500
  public      | user_promo_codes           | table |                   0
  public      | users                      | table |                  50
  public      | vehicle_location_histories | table |                1000
  public      | vehicles                   | table |                  15
(5 rows)

Remove a table and dependent objects with `CASCADE`

In this example, a foreign key from a different table references the table being dropped. Therefore, it’s only possible to drop the table while simultaneously dropping the dependent foreign key constraint using CASCADE.

> SHOW TABLES FROM movr;

  schema_name |         table_name         | type  | estimated_row_count
--------------+----------------------------+-------+----------------------
  public      | rides                      | table |                 500
  public      | user_promo_codes           | table |                   0
  public      | users                      | table |                  50
  public      | vehicle_location_histories | table |                1000
  public      | vehicles                   | table |                  15
(5 rows)

> DROP TABLE users;

pq: "users" is referenced by foreign key from table "vehicles"

To see how users is referenced from vehicles, you can use the SHOW CREATE statement. SHOW CREATE shows how the columns in a table are created, including data types, default values, indexes, and constraints.

> SHOW CREATE TABLE vehicles;

  table_name |                                         create_statement
-------------+---------------------------------------------------------------------------------------------------
  vehicles   | CREATE TABLE public.vehicles (
             |     id UUID NOT NULL,
             |     city VARCHAR NOT NULL,
             |     type VARCHAR NULL,
             |     owner_id UUID NULL,
             |     creation_time TIMESTAMP NULL,
             |     status VARCHAR NULL,
             |     current_location VARCHAR NULL,
             |     ext JSONB NULL,
             |     CONSTRAINT vehicles_pkey PRIMARY KEY (city ASC, id ASC),
             |     CONSTRAINT fk_city_ref_users FOREIGN KEY (city, owner_id) REFERENCES public.users(city, id),
             |     INDEX vehicles_auto_index_fk_city_ref_users (city ASC, owner_id ASC),
             |     FAMILY "primary" (id, city, type, owner_id, creation_time, status, current_location, ext)
             | )
(1 row)

> DROP TABLE users CASCADE;

DROP TABLE

> SHOW TABLES FROM movr;

  schema_name |         table_name         | type  | estimated_row_count
--------------+----------------------------+-------+----------------------
  public      | rides                      | table |                 500
  public      | user_promo_codes           | table |                   0
  public      | vehicle_location_histories | table |                1000
  public      | vehicles                   | table |                  15
(4 rows)

Use a SHOW CREATE TABLE statement to verify that the foreign key constraint has been removed from vehicles.

> SHOW CREATE TABLE vehicles;

  table_name |                                       create_statement
-------------+------------------------------------------------------------------------------------------------
  vehicles   | CREATE TABLE public.vehicles (
             |     id UUID NOT NULL,
             |     city VARCHAR NOT NULL,
             |     type VARCHAR NULL,
             |     owner_id UUID NULL,
             |     creation_time TIMESTAMP NULL,
             |     status VARCHAR NULL,
             |     current_location VARCHAR NULL,
             |     ext JSONB NULL,
             |     CONSTRAINT "primary" PRIMARY KEY (city ASC, id ASC),
             |     INDEX vehicles_auto_index_fk_city_ref_users (city ASC, owner_id ASC),
             |     FAMILY "primary" (id, city, type, owner_id, creation_time, status, current_location, ext)
             | )
(1 row)

Statements

Syntax

Data Types

Spatial Data

Constraints

Required privileges

Synopsis

Parameters

Viewing schema changes

Examples

Setup

Remove a table (no dependencies)

Remove a table and dependent objects with `CASCADE`

See also

​Required privileges

​Synopsis

​Parameters

​Viewing schema changes

​Examples

​Setup

​Remove a table (no dependencies)

​Remove a table and dependent objects with CASCADE

​See also

Required privileges

Synopsis

Parameters

Viewing schema changes

Examples

Setup

Remove a table (no dependencies)

Remove a table and dependent objects with `CASCADE`

See also