This structure is the top level structure encapsulating several type of statements.
type
type.
cnc
is not null,
then checks that all the database objects referenced in the statement actually exist in the connection's database (for example the
table being updated in a UPDATE statement must exist in the connection's database for the check to succeed).
mstruct
is not null,
then checks that all the database objects referenced in the statement i actually referenced in mstruct
(for example the
table being updated in a UPDATE statement must exist in the connection's database for the check to succeed).
s
sub-statement to the
this compound statement.
select
.
fname
will be updated with
the expression expr
.