Cuong Nguyen created SPARK-50883:
------------------------------------
Summary: Support altering multiple columns in the same ALTER TABLE
command
Key: SPARK-50883
URL: https://issues.apache.org/jira/browse/SPARK-50883
Project: Spark
Issue Type: New Feature
Components: SQL
Affects Versions: 3.5.4
Reporter: Cuong Nguyen
Current ALTER TABLE ... ALTER COLUMN syntax only allows altering one column at
a time. For a large table with many columns, we need to run a command for every
column, which can be slow since we need to incur the preprocessing and IO cost
repeatedly.
A new syntax that allows specifying multiple columns can open door for sharing
such cost across multiple column changes. We propose this new syntax
{code:java}
ALTER TABLE table_name ALTER COLUMN {
{ column_identifier | field_name }
{ COMMENT comment |
{ FIRST | AFTER identifier } |
{ SET | DROP } NOT NULL |
TYPE data_type |
SET DEFAULT clause |
DROP DEFAULT }
}{code}
For example:
{code:java}
ALTER TABLE test_table ALTER COLUMN
a COMMENT "new comment",
b TYPE BIGINT,
x.y.z FIRST{code}
This new syntax is backward compatible with the current syntax. To bound the
complexity of the initial support of this syntax we place the following
restrictions:
* Altering the same column multiple times is not allowed
* Altering a parent and a child column (for nested data type) is not allowed.
--
This message was sent by Atlassian Jira
(v8.20.10#820010)
---------------------------------------------------------------------
To unsubscribe, e-mail: issues-unsubscr...@spark.apache.org
For additional commands, e-mail: issues-h...@spark.apache.org
