15.00 - Modifying Row Partitioning - Teradata Database

Teradata Database SQL Data Definition Language Detailed Topics

Teradata Database
Programming Reference

Modifying Row Partitioning Defined With an Updatable DATE, Updatable CURRENT_DATE, or Updatable CURRENT_TIMESTAMP Partitioning Expression

Teradata Database provides a special version of the ALTER TABLE statement for modifying the row partitioning of a table (or WHERE clause of a join index definition) defined with an updatable DATE, updatable CURRENT_DATE, or updatable CURRENT_TIMESTAMP built‑in function called ALTER TABLE TO CURRENT (see “ALTER TABLE TO CURRENT” on page 140).

ALTER TABLE TO CURRENT is designed specifically to reconcile the values of these functions when they are specified in a partitioning expression of a table or join index or in the WHERE clause of a join index.

The rules for ALTER TABLE TO CURRENT requests are identical for row partitioning and column partitioning; however, there can be a negative performance impact if the table or join index has column partitioning in addition to row partitioning because it is often costly to move a row from one row partition to another.

See the table in “Comparing the Capabilities of ALTER TABLE TO CURRENT Requests With ALTER TABLE … REVALIDATE PRIMARY INDEX Requests” on page 140 for a comparison of the capabilities of ALTER TABLE … REVALIDATE PRIMARY INDEX requests with the ALTER TABLE TO CURRENT statement.