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Martijn Tonies · Guest

Hi all,

We all know that dbExpress is a bit limited in some regards.

For example, you cannot pass custom connection options (in
TSQLConnection.Params) to a driver just before connecting.

You cannot set custom properties for commands/queries.

You cannot get the Query Plan for, for example, InterBase or
Firebird.

I recently had a small e-mail exchange with Thomas Miller, the
maintainer of dbExpressPlus.

I proposed extending the dbExpress interfaces and optionally
implementing them in dbExpressPlus. This way, driver creators
could choose to implement them and dbExpressPlus can use
current drivers and drivers that implement the newer interfaces.

To this effect, we would like to know the requirements of people
who are using dbExpress.

What would you like to do when extending dbExpress?

I already gave an example:
- pass everything that's not a valid dbExpress parameter in
TSQLConnection.Params to the driver as plain text.

An example implementation (driver wise) would be:

ISQLConnectionPlus = interface(...)
procedure SetConnectOption(aOption: PChar; aValue: PChar); stdcall;
end;

Another example:
- getting custom values from a (prepared) command:

ISQLCommandPlus = interface(...)
procedure GetCustomProperty(aProperty: PChar; aValue: PChar); stdcall;
end;

Usage (example: Firebird):
Command.GetCustomProperty('PLAN', PlanBuffer);

Comments?

--
With regards,

Martijn Tonies
Database Workbench - developer tool for InterBase, Firebird, MySQL & MS SQL
Server.
Upscene Productions
http://www.upscene.com

Dmitry Arefiev [gs-soft.r · Guest

Hi Martin !

As you know, dbExpress has a lot of issues. I will name
just few:
- no right data types. At least Unicode ones are at most mised.
- no connection parameter enumeration and, of course, no
ability to transfer intermediate parameters
- no right error handling
- no access to CLI handles
- cant cancel a query
- etc (A LOT)

I dont think "Query Plan" should be generelaized. Different
RDMB's will have different approaches. As i got you, IB
requires access to handles. Oracle will get plan from DB
table.

I think ODBC, OLEDB, BDE done what we need. Is not ?
dbExpress is pure commercial step ...

Regards,
Dmitry

--
Dmitry Arefiev, gs-soft Company, community.gs-soft.com
Personal - www.da-soft.com

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Martijn Tonies wrote:

Thomas Miller · Guest

There are some great things about dbExpress too. So just
because they never finished the technology doesn't mean
we shouldn't finish it and keep on going. Obviously
Martin is willing to support the new interface. If
Corelab is too, then we have a lot of drivers available.
I am sure we can work on the open source ODBC driver.

That would only leave a couple of other vendors to
convince to support the newer interface and another
reason for people to buy their drivers.

I like the idea. I would like to see the Metadata
interface much border to support Triggers, Foreign
Keys, Generators, Plan, etc.

If we do this from scratch and properly, then we
can start a real open source project that can be
ported to Free Pascal too.

That is a good list to start with. Any more?

Dmitry Arefiev [gs-soft.ru] wrote:

Martijn Tonies · Guest

Hi Dmitry,