Hi, Alexander,
On Jul 29, Alexander Barkov wrote:
Hello Sergei,
I have a couple of suggestions:
commit 7b8304045272111a6f4d44196d6b37cbfef06f37
Author: Sergei Golubchik <serg@xxxxxxxxxxx>
Date: Wed Jul 20 17:31:48 2022 +0200
MDEV-29075 Changing explicit_defaults_for_timestamp within stored procedure works inconsistently
move the OPTION_EXPLICIT_DEF_TIMESTAMP check from the parsing step
to the execution
diff --git a/sql/field.cc b/sql/field.cc
index 2e0c70d3d13..23ebb07b7f7 100644
--- a/sql/field.cc
+++ b/sql/field.cc
@@ -10824,6 +10824,7 @@ Column_definition::Column_definition(
comment= old_field->comment;
vcol_info= old_field->vcol_info;
option_list= old_field->option_list;
+ explicitly_nullable= !(old_field->flags & NOT_NULL_FLAG);
This introduces asymmetry in how NULL and NOT NULL attributes are handled.
I suggest considering these ways:
1. Change "bool explicitly_nullable" to "bool explicit_nullability",
which will be:
- false if nothing was specified
- true if NULL or NOT NULL was specified.
I've done that, see commit 7120195ac1c,
but I don't like how it looks. When NOT_NULL_FLAG is set, the value is
redundant, it's not used anywhere and only adds few pointless
assignments to sql_yacc.yy.
We only need to know how to interpret the case when NOT_NULL_FLAG is not
set, that's what explicitly_nullable was doing.
2. Or don't store NOT_NULL_FLAG in Column_definition::flags at all.
Add a new Column_definition enum member with three values for:
- not specified
- explicit NULL
- explicit NOT NULL
As discussed on slack, the latter will need some changes.
But I think not that much, as only Column_definition needs changes,
while Field does not seem to need at this point.
I don't know how to do it in a robust way. Column_definition and Field
have both the same flags member, one typically just copies it back and
forth. Having just one bit out of Column_definition::flags is very
error-prone, I'd prefer all flags to be stored very differently in
Column_definition, so that one couldn't just copy them. But this
explicitly_nullable thing cannot justify such a big change.
