Native D MySQL Driver

[Sean Kelly]

On Nov 4, 2011, at 12:05 PM, Steve Teale wrote:

> On Fri, 04 Nov 2011 10:19:23 -0700, bls wrote:
> 
>> On 11/04/2011 09:25 AM, Steve Teale wrote:
>>>  I don't think you need to worry
>>> about changes while stepping through rows.
>> 
> 
> As in don't worry about something over which you have no control!
> 
>> However, there are always many ways to skin a cat. PostgreSQL, Firebird,
>> MSSQL Server (not sure about MySQL) enable you to trigger server side
>> events.
>> Means the database server fires an update event (say employee deleted
>> event) and a D function living in a secondary thread will catch this
>> event and inform all interested parties (subscribers**) to refresh their
>> RowSet. (and of course the UI)
>> 
>> Beside, this is the way we create mission critical,db-centric realtime
>> apps. works fine.
>> My 2 cents.
> 
> Bjoern
> 
> There's not a hint of that in the MySQL protocol. It'a purely command/
> response. The commands are:
...
> I don't see a 'let me know when something happens' command here. There is 
> also no trace of it in the C API.

Unless something has changed in the last few years, the way to do this in MSSQL is via a plugin in the SQL server itself.  Back in the days of yore this was via extended stored procedures, which were loaded as a DLL by the SQL server, but I think more recent iterations can call COM or .NET code or something like that as well.  In short, the event notification isn't typically done via a back-feed through a client connection.  Do any modern DBMSes have pub/sub functionality like this?