Evolve Iceberg table schema

Iceberg schema updates are metadata-only changes. No data files are changed when you perform a schema update.

The Iceberg format supports the following schema evolution changes:

• Add – Adds a new column to a table or to a nested struct.

• Drop – Removes an existing column from a table or nested struct.

• Rename – Renames an existing column or field in a nested struct.

• Reorder – Changes the order of columns.

• Type promotion – Widens the type of a column, struct field, map key, map value, or list element. Currently, the following cases are supported for Iceberg tables:

  • integer to big integer

  • float to double

  • increasing the precision of a decimal type

You can use the DDL statements in this section to modify Iceberg table schema.

Topics

• ALTER TABLE ADD COLUMNS
• ALTER TABLE DROP COLUMN
• ALTER TABLE CHANGE COLUMN
• SHOW COLUMNS