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| author | Peter Eisentraut <peter@eisentraut.org> | 2024-08-29 08:38:29 +0200 |
|---|---|---|
| committer | Peter Eisentraut <peter@eisentraut.org> | 2024-08-29 09:01:02 +0200 |
| commit | cf49a606c416634fd6af82eb559331fd6052835d (patch) | |
| tree | 612d40fbc95fdb2eedfdfb5ad327eb9328a3e4ee | |
| parent | 5d9170697e4e6dd282b015890bc29baf978c6cb5 (diff) | |
| download | postgresql-cf49a606c416634fd6af82eb559331fd6052835d.tar.gz postgresql-cf49a606c416634fd6af82eb559331fd6052835d.zip | |
Disallow USING clause when altering type of generated column
This does not make sense. It would write the output of the USING
clause into the converted column, which would violate the generation
expression. This adds a check to error out if this is specified.
There was a test for this, but that test errored out for a different
reason, so it was not effective.
Reported-by: Jian He <jian.universality@gmail.com>
Reviewed-by: Yugo NAGATA <nagata@sraoss.co.jp>
Discussion: https://www.postgresql.org/message-id/flat/c7083982-69f4-4b14-8315-f9ddb20b9834%40eisentraut.org
| -rw-r--r-- | src/backend/commands/tablecmds.c | 13 | ||||
| -rw-r--r-- | src/test/regress/expected/generated.out | 3 |
2 files changed, 14 insertions, 2 deletions
diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c index 44629fb52f4..4f6bf4c959c 100644 --- a/src/backend/commands/tablecmds.c +++ b/src/backend/commands/tablecmds.c @@ -12308,6 +12308,16 @@ ATPrepAlterColumnType(List **wqueue, colName))); /* + * Cannot specify USING when altering type of a generated column, because + * that would violate the generation expression. + */ + if (attTup->attgenerated && def->cooked_default) + ereport(ERROR, + (errcode(ERRCODE_INVALID_COLUMN_DEFINITION), + errmsg("cannot specify USING when altering type of generated column"), + errdetail("Column \"%s\" is a generated column.", colName))); + + /* * Don't alter inherited columns. At outer level, there had better not be * any inherited definition; when recursing, we assume this was checked at * the parent level (see below). @@ -12383,11 +12393,12 @@ ATPrepAlterColumnType(List **wqueue, (errcode(ERRCODE_DATATYPE_MISMATCH), errmsg("column \"%s\" cannot be cast automatically to type %s", colName, format_type_be(targettype)), + !attTup->attgenerated ? /* translator: USING is SQL, don't translate it */ errhint("You might need to specify \"USING %s::%s\".", quote_identifier(colName), format_type_with_typemod(targettype, - targettypmod)))); + targettypmod)) : 0)); } /* Fix collations after all else */ diff --git a/src/test/regress/expected/generated.out b/src/test/regress/expected/generated.out index 10208484ee5..9ee4559bd5a 100644 --- a/src/test/regress/expected/generated.out +++ b/src/test/regress/expected/generated.out @@ -836,7 +836,8 @@ SELECT * FROM gtest27; (2 rows) ALTER TABLE gtest27 ALTER COLUMN x TYPE boolean USING x <> 0; -- error -ERROR: generation expression for column "x" cannot be cast automatically to type boolean +ERROR: cannot specify USING when altering type of generated column +DETAIL: Column "x" is a generated column. ALTER TABLE gtest27 ALTER COLUMN x DROP DEFAULT; -- error ERROR: column "x" of relation "gtest27" is a generated column HINT: Use ALTER TABLE ... ALTER COLUMN ... DROP EXPRESSION instead. |