ZEOS LIB components ?

[IgD]

Lightning, have you heard any more updates on using Zeoslib with Lazarus?  I want to start using Lazarus with DB stuff but my work won't permit installation of open source DB's.  We are required to use Microsoft SQL Server.

[matthijs]

Cannot you use ODBC components then? I think there is a library to connect through ODBC.

[Lightning]

IgD, not yet completed, we are waiting for a version of FPC with full variant and interfaces support because Zeos uses too much Delphi/Kylix specific syntax, but as soon as FPC will support that kind of syntax we will port all the Zeos code to Lazarus, you could join the Zeos team and help if you want to.

[Stevie]

Hi,

I am a member of the ZeosLib-Team and I tried to port the zeosdbo (6.5.1 alpha) to lazarus/fcp.
But I have some problems porting the component-package to fcp because the db-objects (i.e. TDataSet) in fpc are quite different to the delphi-objects.
Is there a newer version of them available than the version included with the newest lazarus (0.9.6) ?

P.S.: I'm totally new to lazarus... ;-)

Regards
Stevie

[jesusr]

Hi,

I am a member of the ZeosLib-Team and I tried to port the zeosdbo (6.5.1 alpha) to lazarus/fcp.
But I have some problems porting the component-package to fcp because the db-objects (i.e. TDataSet) in fpc are quite different to the delphi-objects.
Is there a newer version of them available than the version included with the newest lazarus (0.9.6) ?

P.S.: I'm totally new to lazarus... ;-)

Regards
Stevie

I'm afraid not too much changes in TDataset.
Can you show what the differences are? what would be the solution?

[Anonymous]

I'm afraid not too much changes in TDataset.
Can you show what the differences are? what would be the solution?

Hello,
some methods are not present (Lookup, Locate), but this is no problem, because they are overwritten anyway.
But there is a serious problem in calling an inherited abstract method
which results in an compilation-error: "Abstract Methods can't be called directly" for which I do not know any solution.
Furthermore I have the error: "Procedure overloading is switched off" BUT the -SO-Switch is off!!
Is there a problem with overloading/overriding and/or abstract methods in FPC??

Regards
Stevie

[jesusr]

I'm afraid not too much changes in TDataset.
Can you show what the differences are? what would be the solution?

Hello,
some methods are not present (Lookup, Locate), but this is no problem, because they are overwritten anyway.
But there is a serious problem in calling an inherited abstract method
which results in an compilation-error: "Abstract Methods can't be called directly" for which I do not know any solution.
Furthermore I have the error: "Procedure overloading is switched off" BUT the -SO-Switch is off!!
Is there a problem with overloading/overriding and/or abstract methods in FPC??

Regards
Stevie

Try to use -Sd for delphi compatibility, perhaps for porting from delphi, this would be better.

if you have more abstract methods problem's, please describe which functions/procedures are failing.

[Marc]

afaik calling an inherited abstract method in Delphi rewsults in an EAbstract exception

[Stevie]

Try to use -Sd for delphi compatibility, perhaps for porting from delphi, this would be better.

if you have more abstract methods problem's, please describe which functions/procedures are failing.

I used the -Sd-Switch already!

The problem was that I did not overload a procedure that is already overloaded in the Delphi-TDataSet but not in FPC and is declared as override.

There are many differences, that are not implemented yet in the TDataSet...

afaik calling an inherited abstract method in Delphi rewsults in an EAbstract exception

In Delphi the method that is called is not abstract, but I worked around it for now.

Ok, now it compiles and i installed the package!

But when I try to open the DataSet an EVariantError raised with the message "Method Unassigned not yet supported" which is raised by the following method in dsparams.inc - i think:

Code: [Select]

constructor TParam.Create(ACollection: TCollection);
begin
  inherited Create(Collection);
  ParamType:=ptUnknown;
  DataType:=ftUnknown;
  FValue:=Unassigned;  // <---
  FNull:=True;
end;

When I try to debug my test-project, I also cannot debug into the db-sources nor into the zeos-sources...

P.S. Is works!!!  :mrgreen: (with a little modification in the variants-unit... )
But still, I have got a question: How must I configure the debugger to step into the units? I worked around it by putting them into my project-path... :oops:

[Marc]

Variant support is not complete in FPC.
The error you get means that the implicit VarClear (when assigning unassigend) is not yet implemented. Chances are that this won't get fixed before FPC 2.0 is released, so your patches are more than welcome if you want it in the 2.0 release.
About debugging dbsources, if you have the FPC sources, you can compile a debug version with

Code: [Select]

make OPT=-g in the fcl and/or packages base dir followed by a

Code: [Select]

make install PREFIX=/your_path_to_a_location_to_install_you_debug_units in those dirs. If you place this location in your fpc.cfg before the other paths, they get used first.

[Stevie]

Variant support is not complete in FPC.
The error you get means that the implicit VarClear (when assigning unassigend) is not yet implemented. Chances are that this won't get fixed before FPC 2.0 is released, so your patches are more than welcome if you want it in the 2.0 release.

I "fixed" it as follows:

Code: [Select]

function Unassigned: Variant; // Unassigned standard constant
begin
//  NotSupported('Unassigned');
  sysvarclear(Result);
end;

About debugging dbsources, if you have the FPC sources, you can compile a debug version with

Code: [Select]

make OPT=-g in the fcl and/or packages base dir followed by a

Code: [Select]

make install PREFIX=/your_path_to_a_location_to_install_you_debug_units in those dirs. If you place this location in your fpc.cfg before the other paths, they get used first.

Does this mean, I have to recompile the sources? Sorry, I am not very familiar with make an these tools...

[Marc]

Does this mean, I have to recompile the sources? Sorry, I am not very familiar with make an these tools...

Yes. By default fpc is shipped with release units without any debug info. So if you want debug info you have to make them yourself.

If you are on linux, the only thin you have to do to type the commands I gave. On win32 you have to make sure that the make shipped in your fpc\bin dir is the first in your path.

[Anonymous]

Ok, I did as you said, but there is still the message "The file dataset.inc was not found. Do you want to locate it yourself?" But no matter if i click on Yes or No the next message is "The file <my_project_path>\dataset.inc does not exist."

I have Lazarus 0.9.6 beta (25.02.2005) on WindowsXP

[Lightning]

Try getting the latest snapshot from http://www.ca.freepascal.org/Lazarus/
Good news

[Stevie]

Try getting the latest snapshot from http://www.ca.freepascal.org/Lazarus/
Good news

Ok, I got the latest version today.
I've installed the packages but there is still the error which I mentioned above. Can anyone give me a detailed description, how to make my lazarus work with debug units? :roll:

Another error which i got was an access violation when setting master/detail with two TZTables. I assume an error in the TDataSet implementation but I did not look more exactly at the DB-Sources.

Another (maybe a little bit off topic) question: Will there be the TDBLookupComboBox or/and TDBLookupListBox in the LCL in future??

P.S.: Ok, search before post... :oops:
I have found this topic(http://www.lazarus.freepascal.org/index.php?name=PNphpBB2&file=viewtopic&t=556&highlight=master+detail) about the master/detail problem/workaround.