diff options
| -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 94fc3a082b2..70cd2669164 100644 --- a/src/backend/commands/tablecmds.c +++ b/src/backend/commands/tablecmds.c @@ -12678,6 +12678,16 @@ 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). @@ -12753,11 +12763,12 @@ 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 44058db7c1d..499072e14ca 100644 --- a/src/test/regress/expected/generated.out +++ b/src/test/regress/expected/generated.out @@ -1026,7 +1026,8 @@ 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. |