Alter Table

Apply various modifications to a table or view. The available modifications include the following:

Manage a table's columns--a column can be added, removed, or have its type and properties modified, including whether it is compressed or not.

External tables cannot be modified except for their refresh method.

Create or delete an index on a particular column. This can speed up certain operations when using expressions containing equality or relational operators on indexed columns. This only applies to tables.

Create or delete a foreign key on a particular column.

Manage a range-partitioned or a manual list-partitioned table's partitions.

Set (or reset) the tier strategy of a table or view.

Refresh and manage the refresh mode of a materialized view or an external table.

Set the time-to-live (TTL). This can be applied to tables or views.

Set the global access mode (i.e. locking) for a table. This setting trumps any role-based access controls that may be in place; e.g., a user with write access to a table marked read-only will not be able to insert records into it. The mode can be set to read-only, write-only, read/write, and no access.

Input Parameter Description

Name

Type

Description

table_name

string

Table on which the operation will be performed, in [schema_name.]table_name format, using standard name resolution rules. Must be an existing table or view.

action

string

Modification operation to be applied

Supported Values	Description
allow_homogeneous_tables	No longer supported; action will be ignored.
create_index	Creates either a column (attribute) index or chunk skip index, depending on the specified index_type, on the column name specified in input parameter value. If this column already has the specified index, an error will be returned.
delete_index	Deletes either a column (attribute) index or chunk skip index, depending on the specified index_type, on the column name specified in input parameter value. If this column does not have the specified index, an error will be returned.
move_to_collection	[DEPRECATED--please use move_to_schema and use Create Schema to create the schema if non-existent] Moves a table or view into a schema named input parameter value. If the schema provided is non-existent, it will be automatically created.
move_to_schema	Moves a table or view into a schema named input parameter value. If the schema provided is non-existent, an error will be thrown. If input parameter value is empty, then the table or view will be placed in the user's default schema.
protected	No longer used. Previously set whether the given input parameter table_name should be protected or not. The input parameter value would have been either 'true' or 'false'.
rename_table	Renames a table or view within its current schema to input parameter value. Has the same naming restrictions as tables.
ttl	Sets the time-to-live in minutes of the table or view specified in input parameter table_name.
add_column	Adds the column specified in input parameter value to the table specified in input parameter table_name. Use column_type and column_properties in input parameter options to set the column's type and properties, respectively.
change_column	Changes type and properties of the column specified in input parameter value. Use column_type and column_properties in input parameter options to set the column's type and properties, respectively. Note that primary key and/or shard key columns cannot be changed. All unchanging column properties must be listed for the change to take place, e.g., to add dictionary encoding to an existing 'char4' column, both 'char4' and 'dict' must be specified in the input parameter options map.
set_column_compression	Modifies the compression setting on the column specified in input parameter value to the compression type specified in compression_type.
delete_column	Deletes the column specified in input parameter value from the table specified in input parameter table_name.
create_foreign_key	Creates a foreign key specified in input parameter value using the format '(source_column_name [, ...]) references target_table_name(primary_key_column_name [, ...]) [as foreign_key_name]'.
delete_foreign_key	Deletes a foreign key. The input parameter value should be the foreign_key_name specified when creating the key or the complete string used to define it.
add_partition	Adds the partition specified in input parameter value, to either a range-partitioned or manual list-partitioned table.
remove_partition	Removes the partition specified in input parameter value (and relocates all of its data to the default partition) from either a range-partitioned or manual list-partitioned table.
delete_partition	Deletes the partition specified in input parameter value (and all of its data) from either a range-partitioned or manual list-partitioned table.
set_global_access_mode	Sets the global access mode (i.e. locking) for the table specified in input parameter table_name. Specify the access mode in input parameter value. Valid modes are 'no_access', 'read_only', 'write_only' and 'read_write'.
refresh	For a materialized view, replays all the table creation commands required to create the view. For an external table, reloads all data in the table from its associated source files or data source.
set_refresh_method	For a materialized view, sets the method by which the view is refreshed to the method specified in input parameter value - one of 'manual', 'periodic', or 'on_change'. For an external table, sets the method by which the table is refreshed to the method specified in input parameter value - either 'manual' or 'on_start'.
set_refresh_start_time	Sets the time to start periodic refreshes of this materialized view to the datetime string specified in input parameter value with format 'YYYY-MM-DD HH:MM:SS'. Subsequent refreshes occur at the specified time + N * the refresh period.
set_refresh_period	Sets the time interval in seconds at which to refresh this materialized view to the value specified in input parameter value. Also, sets the refresh method to periodic if not already set.
set_refresh_execute_as	Sets the user name to refresh this materialized view to the value specified in input parameter value.
remove_text_search_attributes	Removes text search attribute from all columns.
set_strategy_definition	Sets the tier strategy for the table and its columns to the one specified in input parameter value, replacing the existing tier strategy in its entirety.
cancel_datasource_subscription	Permanently unsubscribe a data source that is loading continuously as a stream. The data source can be kafka / S3 / Azure.
pause_datasource_subscription	Temporarily unsubscribe a data source that is loading continuously as a stream. The data source can be kafka / S3 / Azure.
resume_datasource_subscription	Resubscribe to a paused data source subscription. The data source can be kafka / S3 / Azure.

value

string

The value of the modification, depending on input parameter action. For example, if input parameter action is add_column, this would be the column name; while the column's definition would be covered by the column_type, column_properties, column_default_value, and add_column_expression in input parameter options. If input parameter action is ttl, it would be the number of minutes for the new TTL. If input parameter action is refresh, this field would be blank.

options

map of string to strings

Optional parameters. The default value is an empty map ( {} ).

Supported Parameters (keys)

Parameter Description

action

column_name

table_name

column_default_value

When adding a column, set a default value for existing records. For nullable columns, the default value will be null, regardless of data type.

column_properties

When adding or changing a column, set the column properties (strings, separated by a comma: data, store_only, text_search, char8, int8 etc).

column_type

When adding or changing a column, set the column type (strings, separated by a comma: int, double, string, null etc).

compression_type

When setting column compression (set_column_compression for input parameter action), compression type to use: none (to use no compression) or a valid compression type. The default value is snappy. The supported values are:

none
snappy
lz4
lz4hc

copy_values_from_column

[DEPRECATED--please use add_column_expression instead.]

rename_column

When changing a column, specify new column name.

validate_change_column

When changing a column, validate the change before applying it (or not). The default value is true.

Supported Values	Description
true	Validate all values. A value too large (or too long) for the new type will prevent any change.
false	When a value is too large or long, it will be truncated.

update_last_access_time

Indicates whether the time-to-live (TTL) expiration countdown timer should be reset to the table's TTL. The default value is true.

Supported Values	Description
true	Reset the expiration countdown timer to the table's configured TTL.
false	Don't reset the timer; expiration countdown will continue from where it is, as if the table had not been accessed.

add_column_expression

When adding a column, an optional expression to use for the new column's values. Any valid expression may be used, including one containing references to existing columns in the same table.

strategy_definition

Optional parameter for specifying the tier strategy for the table and its columns when input parameter action is set_strategy_definition, replacing the existing tier strategy in its entirety.

index_type

Type of index to create, when input parameter action is create_index, or to delete, when input parameter action is delete_index. The default value is column.

Supported Values	Description
column	Create or delete a column (attribute) index.
chunk_skip	Create or delete a chunk skip index.

Output Parameter Description

Name	Type	Description
table_name	string	Table on which the operation was performed.
action	string	Modification operation that was performed.
value	string	The value of the modification that was performed.
type_id	string	return the type_id (when changing a table, a new type may be created)
type_definition	string	return the type_definition (when changing a table, a new type may be created)
properties	map of string to arrays of strings	return the type properties (when changing a table, a new type may be created)
label	string	return the type label (when changing a table, a new type may be created)
info	map of string to strings	Additional information.