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#1 mORMot 1 » Messenging between Apps » 2012-05-15 15:28:01

deathsfriend
Replies: 2

Hi There,

So in my current project, I have a windows service and several desktop apps which communicate with the service using mORMot to store data in a small SQLLite Database.

The windows service is using Named Pipes to communicate with the client.

Is there anyway for my desktop apps to use the existing connection to send messages not related to database access ? If so, how would I do that? I can't find a demo for sending messages back and forth.

Thanks

#2 Re: mORMot 1 » Questions and Assistance required... » 2012-05-15 15:25:54

deathsfriend
ab wrote:

This is a weird issue.

I can't understand why EngineExecuteFmt fails, and not EngineExecute.

Is the following code working:
Database.EngineExecuteFmt( 'DELETE FROM % WHERE ID <= %',
                                  [recTemp.SQLTableName,tblTemp.IDColumnHiddenValue(rowCount)],[] )

Perhaps this is a "prepared statement" issue, if the ? parameters are not working as expected.

Did you retrieve the latest version of mORMot from http://synopse.info/fossil/wiki?name=Get+the+source ?
There was an issue with hashing, in some cases, as far as I remember.

I'm using the latest version; and your code above works. My original code doesn't... the only difference seems to be the ? so it maybe its the hashing.

#3 Re: mORMot 1 » Questions and Assistance required... » 2012-05-14 23:44:57

deathsfriend
ab wrote:

Could you use the debugger, then step into the EngineExecuteFmt() method - i.e. the EngineExecute() function - and see where its execution is aborted.

I fixed the issue just before you posted, and haven't been able to report back with my findings.

Basically, switching out the line

Database.EngineExecuteFmt( 'DELETE FROM % WHERE ID <= ?',
                                  [recTemp.SQLTableName],
                                  [tblTemp.IDColumnHiddenValue(rowCount)] )

for

sqlStr := Format( 'DELETE FROM %s WHERE ID <= %d',[ recTemp.SQLTableName, tblTemp.IDColumnHiddenValue(rowCount)] );
if(Database.EngineExecute( sqlStr ))then

And it magically started working once again (I hate this method of doing it, btw - I'd like to use EngineExecuteFmt).

If I use the EngineExecuteFmt line, it breaks, but EngineExecute is fine. In case it helps, this is a relatively straight forward setup; I have a named pipe server running in a Windows Service, with serveral desktop applications feeding into it. I'm not bothered about user authentication (At this point).

Is there a demo of authentication, and how to use it/manage it ?

#4 Re: mORMot 1 » Questions and Assistance required... » 2012-05-14 09:43:09

deathsfriend
ab wrote:
deathsfriend wrote:

Do I need to give it full rights ?

Two other options are for services.
Be aware that some low-level functions of the framework uses internally services.

So for supervisor rights, it could make sense to add reService!

Even using the line;

SUPERVISOR_ACCESS_RIGHTS.AllowRemoteExecute := [reSQL,reService, reUrlEncodedSQL];

doesn't work. The following SQL Statement never runs;

Database.EngineExecuteFmt( 'DELETE FROM % WHERE ID <= ?',
                                  [recTemp.SQLTableName],
                                  [tblTemp.IDColumnHiddenValue(rowCount)] )

It always returns false, and nothing is deleted. This worked previously; so what am I missing here?

#5 Re: mORMot 1 » Questions and Assistance required... » 2012-05-09 09:33:54

deathsfriend

Hi,

So I managed to solve the refresh issue with a code update.

However, thats broken one important part.

I was using

SUPERVISOR_ACCESS_RIGHTS.AllowRemoteExecute := true;

To enable the clients to execute SQL statements. However, the latest code update changed AllowRemoteExecute from Boolean to TSQLAllowRemoteExecute = set of (reSQL, reService, reUrlEncodedSQL);

I tried to use the line;

SUPERVISOR_ACCESS_RIGHTS.AllowRemoteExecute := [reSQL];

Do I need to give it full rights ?

#6 mORMot 1 » Questions and Assistance required... » 2012-04-27 13:37:37

deathsfriend
Replies: 8

Hi All,

First, loving the framework. I've got it working in a project i'm working on right now and loving it.

However, I have some questions.

1. How can I update the contents of a TableToGrid?

The following code works fine for small databases ( 5 -6 records, tops). It even displays the Grid correctly for large record sets when its first displayed.

But when I try to refresh the Grid with a database containing 65,000 records, it crashes with an EAccessViolation exception;

procedure TfrmMain.RefreshRecords;
var
  rowCount : Integer;
begin

  if not(Assigned(TableToGrid))then
  begin
    Database.Update( Rec );

    rowCount := Database.TableRowCount( TSQLSampleRecord );
    lblRecordCount.Caption := Format ( '%d Records Available', [rowCount] );

    TableToGrid := TSQLTableToGrid.Create( Self.grdData,
                                           Rec.FillTable,
                                           Database );

    Rec.FillTable.OwnerMustFree := False;
  end
  else
  begin
    Database.Update( Rec );

    rowCount := Database.TableRowCount( TSQLSampleRecord );
    lblRecordCount.Caption := Format ( '%d Records Available', [rowCount] );

    if(TableToGrid.Refresh(True))then
        TableToGrid.Refresh();    // << Crashes here
  end;
end;

How do I get around that ?

2. How I can execute an SQL Query against a table - for example, I want to delete all the records where ID < X (Where X is a value the user entered, or the result of a calculation).
Currently I step though the database - there has got to be a faster way.

3. When a database grows, can it be shrunk on the disk ? For example with 66,000 records it grows to 5Mb. Can we Shrink the file back down ?

Cheers

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