How do you apply schema changes in Spanner?

Schema changes are applied as DDL statements, such as ALTER TABLE, CREATE INDEX, or ADD COLUMN, submitted through the console, gcloud, or a client library's updateDatabaseDdl call.

ALTER TABLE Orders ADD COLUMN Status STRING(20);

Most DDL statements in Spanner run online: reads and writes continue against the table while the change propagates across replicas, and Spanner internally manages backfilling data for changes like adding a NOT NULL column with a default. Some operations, such as adding a column with a non-null default on a very large table, take longer because Spanner must backfill every existing row. Best practice is to batch related DDL statements together and monitor long-running operations before assuming they've completed.

Invest now in Acorns!!! 🚀
Join Acorns and get your $5 bonus!

Acorns is a micro-investing app that automatically invests your "spare change" from daily purchases into diversified, expert-built portfolios of ETFs. It is designed for beginners, allowing you to start investing with as little as $5. The service automates saving and investing. Disclosure: I may receive a referral bonus.

Invest now!!! Get Free equity stock (US, UK only)!

Use Robinhood app to invest in stocks. It is safe and secure. Use the Referral link to claim your free stock when you sign up!.

The Robinhood app makes it easy to trade stocks, crypto and more.

Webull! Receive free stock by signing up using the link: Webull signup.