MDEV-22602 Disable UPDATE CASCADE for SQL constraints

CHECK constraint is checked by check_expression() which walks its
items and gets into Item_field::check_vcol_func_processor() to check
for conformity with foreign key list.

WITHOUT OVERLAPS is checked for same conformity in
mysql_prepare_create_table().

Long uniques are already impossible with InnoDB foreign keys. See
ER_CANT_CREATE_TABLE in test case.

2 accompanying bugs fixed (test main.constraints failed):

1. check->name.str lived on SP execute mem_root while "check" obj
itself lives on SP main mem_root. On second SP execute check->name.str
had garbage data. Fixed by allocating from thd->stmt_arena->mem_root
which is SP main mem_root.

2. CHECK_CONSTRAINT_IF_NOT_EXISTS value was mixed with
VCOL_FIELD_REF. VCOL_FIELD_REF is assigned in check_expression() and
then detected as CHECK_CONSTRAINT_IF_NOT_EXISTS in
handle_if_exists_options().

Existing cases for MDEV-16932 in main.constraints cover both fixes.

0 files changed, 0 insertions, 0 deletions