ALTER Command Reference

Description

Modifies the definition, properties, or configuration of an existing object in Singdata Lakehouse.

Syntax

ALTER <object_type> <object_name> <actions>

Parameter Description

Parameter	Description	Required
<object_type>	The type of object to modify, e.g., TABLE, SCHEMA, VCLUSTER	Yes
<object_name>	The name of the object, which may include a schema prefix	Yes
<actions>	The specific operation, e.g., ADD COLUMN, SET COMMENT, RENAME TO	Yes

Supported Object Types

Object Type	Syntax Example	Description
Workspace	ALTER WORKSPACE <name> SET ...	Modify workspace configuration
Compute Cluster	ALTER VCLUSTER <name> ...	Modify VCluster specification/status
Data Share	ALTER SHARE <name> ...	Modify Share configuration
Schema	ALTER SCHEMA <name> ...	Modify Schema properties
External Schema	ALTER EXTERNAL SCHEMA <name> ...	Modify external Schema configuration
Regular Table	ALTER TABLE <name> ...	Modify table properties, add/drop columns, etc.
Table Column	ALTER TABLE <name> ALTER COLUMN ...	Column-level structural changes
Dynamic Table	ALTER DYNAMIC TABLE <name> ...	Suspend/resume/rename a dynamic table
Materialized View	ALTER MATERIALIZED VIEW <name> ...	Modify materialized view properties
External Table	ALTER EXTERNAL TABLE <name> ...	Modify external table configuration
Pipe	ALTER PIPE <name> ...	Modify Pipe scheduling configuration
User	ALTER USER <name> ...	Modify user properties

Permission Requirements

Executing an ALTER operation generally requires OWNERSHIP or corresponding administrative privileges on the target object. Some operations (e.g., modifying VCLUSTER configuration) also require workspace-level administrative privileges.

Notes

• The ALTER statement is used to modify existing objects without the need to drop and recreate them.
• ALTER TABLE COLUMN is specifically for column-level structural changes (add, drop, modify columns).
• Dynamic tables do not support modifying their SQL definition via ALTER; use CREATE OR REPLACE instead.

Syntax Reference

Instances and Workspaces

• ALTER WORKSPACE

Compute and Sharing

• ALTER VCLUSTER
• ALTER SHARE

Schema and Catalog

• ALTER SCHEMA
• ALTER EXTERNAL SCHEMA

Data Objects

• ALTER TABLE
• ALTER TABLE COLUMN
• ALTER DYNAMIC TABLE
• ALTER MATERIALIZED VIEW
• ALTER EXTERNAL TABLE

Pipes and Connections

• ALTER PIPE

Users and Roles

• ALTER USER