Icon View Thread

The following is the text of the current message along with any replies.
Messages 1 to 7 of 7 total
Thread Dataset question and IIS
Tue, Jul 7 2015 7:26 AMPermanent Link

Michael Dreher

Hi,
I am asking for some starting help.

1) I've managed to create and configure an EWB Module. This is because we use Sybase Adaptive Anywhere as the DB system with database connection authentication, which is handled in the module and works fine. The dataset adapter in the module deligates the DB handling to a TDataSet descendant.

Loading the tabledata in the EWB browser application fills the dataset and a associated TEdit Component (to make the contents visible) via the dataset property (I can debug the incomming request in the module DLL), local navigation (next/prior) works as expected, but I can't change the data and update the database (the DLL is not called on TDataset::Save command).

The main code is this:
-------------------------------------------------------
procedure TForm1.Form1Create(Sender: TObject);
begin
 Database.BaseURL := 'datasets'; // namespace -> see config = datasets = default
 Database.BaseURL := 'customdatasets'; // namespace -> remap to Custom Module
 LoadFromServer;
end;

procedure TForm1.ShowLoadProgress;
begin
  Application.Surface.ShowProgress('Loading....');
end;

procedure TForm1.LoadFromServer;
begin
  ShowLoadProgress;
  Database.LoadRows(ds);
end;

procedure TForm1.btDataSetSaveClick(Sender: TObject);
begin
 ds.Update; // Use this method to begin updating the active row in the dataset.
 ds.Columns['WGWareGroupDescription'].AsString := 'Verkaufsartikel 2';
 ds.Save;   // Use this method to complete an Insert or Update operation.
end;
-------------------------------------------------------
Any idea?

2) What about the primary key definitions of tables(using for UPDATEs and DELETEs); is the TEwbDataSetAdapter able to get the primary key information itself, or do I have to give this information at some place?

3) Our customer want the IIS as the websever. How does the EWB-Module DLL fits in here?
Do I have to write an ISAPI Filter or redirect incomming requersts from the IIS when addressing the

  ///  http://<Domain Name>/<Modules Resource Name>/<Module Name> or
  ///  https://<Domain Name>/<Modules Resource Name>/<Module Name>

scheme?

Regards,
Michael Dreher
Tue, Jul 7 2015 9:00 AMPermanent Link

Raul

Globestar Systems

Team Elevate Team Elevate

On 7/7/2015 7:26 AM, Michael Dreher wrote:
> 1) I've managed to create and configure an EWB Module. This is because we use Sybase Adaptive Anywhere as the DB system with database connection authentication, which is handled in the module and works fine. The dataset adapter in the module deligates the DB handling to a TDataSet descendant.
> Loading the tabledata in the EWB browser application fills the dataset and a associated TEdit Component (to make the contents visible) via the dataset property (I can debug the incomming request in the module DLL), local navigation (next/prior) works as expected, but I can't change the data and update the database (the DLL is not called on TDataset::Save command).

You need to start a transaction and commit in EWB for any data to be
sent back to server - otherwise all edits are local to dataset in the
EWB itself.


See here in manual :

http://www.elevatesoft.com/manual?action=viewtopic&id=ewb2&topic=Transactions

Raul
Tue, Jul 7 2015 1:56 PMPermanent Link

Tim Young [Elevate Software]

Elevate Software, Inc.

Avatar

Email timyoung@elevatesoft.com

Michael,

<< Loading the tabledata in the EWB browser application fills the dataset
and a associated TEdit Component (to make the contents visible) via the
dataset property (I can debug the incomming request in the module DLL),
local navigation (next/prior) works as expected, but I can't change the data
and update the database (the DLL is not called on TDataset::Save command).
>>

As Raul indicated, you need to use transactions in order to have updates be
sent back to the web server application/modules:

procedure TForm1.btDataSetSaveClick(Sender: TObject);
begin
 Database.StartTransaction;
 ds.Update; // Use this method to begin updating the active row in the
dataset.
 ds.Columns['WGWareGroupDescription'].AsString := 'Verkaufsartikel 2';
 ds.Save;   // Use this method to complete an Insert or Update operation.
 Database.Commit;
end;

You can use an Database.OnCommitError event handler to rollback or retry a
commit that fails.

<< 2) What about the primary key definitions of tables(using for UPDATEs and
DELETEs); is the TEwbDataSetAdapter able to get the primary key information
itself, or do I have to give this information at some place? >>

You have to use an event handler for the TEWBDataSetAdapter.OnInitialize
event in order to provide this information to the dataset adapter.  Here's
an example of this from the datasetmodule sample module project included
with EWB:

procedure TExampleDataSetModule.BiolifeAdapterInitialize(
 Adapter: TEWBDataSetAdapter);
var
  I: Integer;
  TempIndexDef: TIndexDef;
  TempFieldName: String;
begin
  { If we're dealing with a table, then we can go ahead and automatically
    set the key field information here.  If not, then code will have to
    be manually added to identify the key fields.  They key fields are used
    to when updating the dataset, as well as when loading BLOBs such as
images.
    It should normally correspond to the primary key for the table
underlying
    the dataset, but a unique key can be used also. }
  Adapter.KeyFields:='';
  Adapter.NumKeyFields:=0;
  if (Adapter.Dataset <> nil) and (Adapter.DataSet is TEDBTable) then
     begin
     with TEDBTable(Adapter.DataSet) do
        begin
        IndexDefs.Update;
        TempIndexDef:=nil;
        for I:=0 to IndexDefs.Count-1 do
           begin
           if (ixPrimary in IndexDefs[I].Options) then
              begin
              TempIndexDef:=IndexDefs[I];
              Break;
              end;
           end;
        if (TempIndexDef=nil) then
           begin
           for I:=0 to IndexDefs.Count-1 do
              begin
              if (ixUnique in IndexDefs[I].Options) then
                 begin
                 TempIndexDef:=IndexDefs[I];
                 Break;
                 end;
              end;
           end;
        if (TempIndexDef <> nil) then
           begin
           with TempIndexDef do
              begin
              I:=1;
              while (I <= Length(Fields)) do
                 begin
                 TempFieldName:=ExtractFieldName(Fields,I);
                 if (Adapter.KeyFields <> '') then
                    Adapter.KeyFields:=(Adapter.KeyFields+';');
                 Adapter.KeyFields:=(Adapter.KeyFields+TempFieldName);
                 Adapter.NumKeyFields:=(Adapter.NumKeyFields+1);
                 end;
              end;
           end;
        end;
     end;
end;

Queries are a little more difficult, but not by much because updateable
queries are normally only a single table.  You simply need to know the base
table name of the query.

<< 3) Our customer want the IIS as the websever. How does the EWB-Module DLL
fits in here? >>

It doesn't, at least for now.  You'll have to use the WebBroker
functionality included with Delphi to create a WebBroker module instead.
However, the good part is that all of the database/dataset adapter code
stays the same.

If you have any other questions, please let me know.

Tim Young
Elevate Software
www.elevatesoft.com
Thu, Jul 9 2015 8:03 AMPermanent Link

Helli

f&t Software GmbH

Michael Dreher's writing (using the account of my boss, because of the support policy update, and this accout has a customer ID).

Thanks for answer. After using the Transaction and setting up the primary key fields  (and hours seaching my programm bugs) writing back to the database was successfull.

"Tim Young [Elevate Software]" wrote:

  //  Queries are a little more difficult, but not by much because updateable
  //  queries are normally only a single table.  You simply need to know the base
  //  table name of the query.

I had to use the query component, a TTable descendant is not supported bei our component supplyer (NativeDB). The hard work was to find out the reason for Exceptions in
     
   dbAdapter1.HandleRequest(Request,'customdatasets');

like "Invalid Argument" without any info about the context (SQL, paraemeters, keys) or the the invalid argument value itself.

  // << 3) Our customer want the IIS as the websever.
  //  How does the EWB-Module DLL
  // fits in here? >>

  // It doesn't, at least for now.  You'll have to use the WebBroker
  // functionality included with Delphi to create a WebBroker module instead.
  // However, the good part is that all of the database/dataset adapter code
  // stays the same.

Now I've to move to the IIS without the EWB Server and the TEWBModule, using the WebBroker and the database- and dataset-adaptors. I hope the EWB IDE- and module-manuals are complete in that an extersion DLL for the IIS can be drived from this.

Thanks again
Michael Dreher
Thu, Jul 9 2015 12:23 PMPermanent Link

Tim Young [Elevate Software]

Elevate Software, Inc.

Avatar

Email timyoung@elevatesoft.com

Michael,

<< Michael Dreher's writing (using the account of my boss, because of the
support policy update, and this accout has a customer ID). >>

Just so you know, you can have multiple user accounts associated with a
given customer ID.  Just update your user profile here:

http://www.elevatesoft.com/user?action=view

using the "Update User Profile" link in the upper-right corner, and set your
customer information:

Customer #
Customer ID
Customer Password

After you're done, you'll both be able to access any applicable downloads
and post on the support forums.

<< Thanks for answer. After using the Transaction and setting up the primary
key fields  (and hours seaching my programm bugs) writing back to the
database was successfull.  >>

Good, I'm glad that itís working for you.

<< I had to use the query component, a TTable descendant is not supported
bei our component supplyer (NativeDB). The hard work was to find out the
reason for Exceptions in

   dbAdapter1.HandleRequest(Request,'customdatasets');

like "Invalid Argument" without any info about the context (SQL,
paraemeters, keys) or the the invalid argument value itself. >>

Hmm, I'm not sure where that exception is coming from, but itís not coming
directly from our code.  You received it with a HandleRequest call ?  Do you
remember the details of how you called the method when the error occurred ?

<< Now I've to move to the IIS without the EWB Server and the TEWBModule,
using the WebBroker and the database- and dataset-adaptors. I hope the EWB
IDE- and module-manuals are complete in that an extersion DLL for the IIS
can be drived from this. >>

Well, I forgot to mention that you won't be able to still use the
HandleRequest method - that uses the TEWBServerRequest class, which is part
of the EWB module code.  What I may end up doing is just modify the
TEWBModule code to support ISAPI DLL generation.  Let me look into this
further, and I'll see whatís involved.

Tim Young
Elevate Software
www.elevatesoft.com


Mon, Oct 5 2015 1:22 AMPermanent Link

Michael Dreher

Tim,

  //  "Tim Young [Elevate Software]" wrote:
  //  
  //  Well, I forgot to mention that you won't be able to still use the
  //  HandleRequest method - that uses the TEWBServerRequest class, which is part
  //  of the EWB module code.  What I may end up doing is just modify the
  //  TEWBModule code to support ISAPI DLL generation.  Let me look into this
  //  further, and I'll see whatís involved.

we're still using ewbsrv with the TEWBModule and have to go to the IIS. When do you expect the TEWBModule supports the ISAPI DLL generation?

Michael Dreher
Mon, Oct 5 2015 10:49 AMPermanent Link

Tim Young [Elevate Software]

Elevate Software, Inc.

Avatar

Email timyoung@elevatesoft.com

Michael,

<< we're still using ewbsrv with the TEWBModule and have to go to the IIS. When do you expect the TEWBModule supports the ISAPI DLL generation? >>

I don't know yet.  I still have to start putting together the 2.03 list of enhancements, and ISAPI support inclusion depends upon what's going into 2.03 in terms of new controls.

Tim Young
Elevate Software
www.elevatesoft.com
Image