Schema modifications

Modify the schema of compressed hypertables

Old API since 2.18.0. Superseded by hypercore. However, compression APIs are still supported, you do not need to migrate to the hypercore APIs.

You can modify the schema of compressed hypertables in recent versions of .

Schema modification	Before TimescaleDB 2.1	TimescaleDB 2.1 to 2.5	TimescaleDB 2.6 and above
Add a nullable column	❌	✅	✅
Add a column with a default value and a NOT NULL constraint	❌	❌	✅
Rename a column	❌	✅	✅
Drop a column	❌	❌	✅
Change the data type of a column	❌	❌	❌

To perform operations that aren’t supported on compressed s, first decompress the table.

Add a nullable column

To add a nullable column:

ALTER TABLE <hypertable> ADD COLUMN <column_name> <datatype>;

For example:

ALTER TABLE conditions ADD COLUMN device_id integer;

Note that adding constraints to the new column is not supported before v2.6.

Add a column with a default value and a NOT NULL constraint

To add a column with a default value and a not-null constraint:

ALTER TABLE <hypertable> ADD COLUMN <column_name> <datatype>
    NOT NULL DEFAULT <default_value>;

For example:

ALTER TABLE conditions ADD COLUMN device_id integer
    NOT NULL DEFAULT 1;

Rename a column

To rename a column:

ALTER TABLE <hypertable> RENAME <column_name> TO <new_name>;

For example:

ALTER TABLE conditions RENAME device_id TO devid;

Drop a column

You can drop a column from a compressed , if the column is not an orderby or segmentby column. To drop a column:

ALTER TABLE <hypertable> DROP COLUMN <column_name>;

For example:

ALTER TABLE conditions DROP COLUMN temperature;