Re: what are java specsification? what are reference implementation?
On 09.08.2014 03:37, Roedy Green wrote:
The idea was people without budget could use a free implementation,
and if the project were a roaring success, they could relatively
easily migrate to a more gold plated implementation.
SQL is the granddaddy of this sort of thinking. The problem is the
spec is so loose, it is a major task to migrate to a different
engine.. They don't even use identical syntax for identical
functions, and there is no guarantee even basic functionality has to
be supported.
It is time a new tighter spec.
I don't think the spec is to blame. The issue is that implementations
were around before the different versions of the spec and vendors chose
compatibility to their older versions over compatibility to a recent
standard of SQL. In some cases there is no way to provide both -
standard and custom syntax at the same time (e.g. Oracle's data type
DATE which is really a timestamp while in the standard it is really a
date only).
So, as always, having a good specification is one thing - the adherence
of implementations to the spec is another. With commercial vendors
there is usually a tendency to provide features that break or at least
extend a standard to allow for vendor lock in. As you can see, in case
of Oracle databases that works pretty well. Of course, users of those
products would prefer more independence but they seem to have enough
advantages of using a proprietary product to continue to do so.
Cheers
robert