Thiez wrote:
On Sunday, 7 October 2012 at 12:39:35 UTC, Piotr Szturmaj wrote:
In my prostgres client one may specify field types at compile time. If
I had divided the client into two separate layers it would return a
Variant[] at first layer, then convert it to user specified tuple at
the second. For example:
auto cmd = new SqlCommand(connection, "SELECT 1, 'abc'");
auto untypedRow = connection.executeRow(); // return DBRow!(Variant[])
auto typedRow = connection.executeRow!(int, string)(); // returns
DBRow!(int, string);
Internally executeRow could always take a Variant[], then convert it
to Tuple!(int, string), but it's suboptimal. Firstly, it must allocate
an array of two Variants, then each Variant must be coerced to the
corresponding type.
Just wanted to illustrate that "layers" shouldn't always be separate.
It's not a very convincing illustration. In practice the overhead of
those operations would likely be completely insignificant compared to
performing the actual database query. Avoiding intermediate layers for
optimality's sake seems like a bad case of premature optimization to me.
In my opinion everything counts. For thousands of rows x thousands of
clients it certainly _should_ make a difference. And I wouldn't call it
premature optimization, it's just _designed_ to be fast.
