This documentation is for an unreleased version of Apache Paimon. We recommend you use the latest stable version.

Default Value #

Paimon allows specifying default values for columns. When users write to these tables without explicitly providing values for certain columns, Paimon automatically generates default values for these columns.

Create Table #

You can create a table with columns with default values using the following SQL:

CREATE TABLE my_table (
    a BIGINT,
    b STRING DEFAULT 'my_value',
    c INT DEFAULT 5 
);

Insert Table #

For SQL commands that execute table writes, such as the INSERT, UPDATE, and MERGE commands, the DEFAULT keyword or NULL value is parsed into the default value specified for the corresponding column.

Alter Default Value #

Paimon supports alter column default value.

For example:

CREATE TABLE T (a INT, b INT DEFAULT 2);

INSERT INTO T (a) VALUES (1);
-- result: [[1, 2]]

ALTER TABLE T ALTER COLUMN b SET DEFAULT 3;

INSERT INTO T (a) VALUES (2);
-- result: [[1, 2], [2, 3]]

The default value of 'b' column has been changed to 3 from 2.

Limitation #

Not support alter table add column with default value, for example: ALTER TABLE T ADD COLUMN d INT DEFAULT 5;.