Why?

Because I'm having fun, thats why!!!

    the Madhatter database Engine has grown to its present state 
through quite a lot of effort and quite a lot of inspiration.  In 
its present state the engine itself is fully functional, though 
with some minor bugs.  I have been working on some visual aspects 
of the engine for some time and have not done any work on the table 
code in a while. 
    The code has progressed from including the cpp and h files into 
a project to access the tables, up to now, were we have a dll and two 
components.  The Dll can be used or the source files depending upon 
the desires of the developer.  The two components are the engine as 
a nonvisual component (MHDBEngine), and a StringGrid (MHDBStringGrid). 
    I hope the functionality of these two will approach the ease of 
use of the BDE, while maintaing a small footprint on the pc.  Afterall 
I do not intend to give microsoft any competition.  I just want a 
serviceable DBE, designed to handle a million or so records, small by 
normal standards. 
 
    Both exaamples below will populate a string grid object that has
been derived from TStringGrid.  this object is designed to function
with the madhatter database engine.

    The following code is an example of utilizing the DLL for the 
database activity.  In the Project cpp we add the path to the file 
"mhdb001.lib".  this is the library for the "mhdb001.dll".  The DLL 
is of course made available in the search path. 
 

#include <vcl.h> 
#pragma hdrstop 
USERES("Project1.res"); 
USEFORM("Unit1.cpp", Form1); 
USELIB("..\MHDBE\full version\dll\mhdb001.lib"); 

//--------------------------------------------------------------------------- 
WINAPI WinMain(HINSTANCE, HINSTANCE, LPSTR, int) 

    try 
    { 
         Application->Initialize(); 
         Application->CreateForm(__classid(TForm1), &Form1); 
         Application->Run(); 
    } 
    catch (Exception &exception) 
    { 
         Application->ShowException(&exception); 
    } 
    return 0; 

//--------------------------------------------------------------------------- 

    This is the Inclulde directive to be added to the top of the Unit.  We must 
ensure that the other h files that are linked to this file are available in the 
project folder or the paths are correct in the declaration.  These others are 
"MHDBFields.h", "MHDBFields.h", "MHDBInternals.h", "MHDBVer.h". 

#include "MHDBTable.h" 

void __fastcall TForm1::Open1Click(TObject *Sender) 

    MHDBTable *TablePtr = new MHDBTable (); 
    if (OpenDialog1->Execute ()) 
    { 
        if (TablePtr) 
        { 
            TablePtr->TableName (OpenDialog1->FileName.c_str ()); 

            if (!TablePtr->Open ()) 
            { 
                MHDBStringGrid1->LoadTabel(TablePtr); 
            } 
            else 
                ShowMessage ("error"); 
        } 
    } 

//--------------------------------------------------------------------------- 

    Thats all there is to it.  Im sure that things will be different in a year, 
but for now I am happy. 

    The code below is for utilizing both components.  We do not have to do 
much other than drag and drop here. The include files  must be made available 
also. 

void __fastcall TForm1::EngineComponent1Click(TObject *Sender) 

    if (OpenDialog1->Execute ()) 
    { 
        if (MHDBEngine1->Table) 
        { 
            MHDBEngine1->Table->TableName (OpenDialog1->FileName.c_str ()); 

            if (!MHDBEngine1->Table->Open ()) 
            { 
                MHDBStringGrid1->LoadTabel(MHDBEngine1->Table); 
            } 
            else 
                ShowMessage ("error"); 
        } 
    } 

//--------------------------------------------------------------------------- 

The code that is displayed here will show the direction that I am going in.  It has bugs and is very 
immature.  Please allow it  the luxury of experiencing its own adolescence.  If you wish to comment 
feel free to email me at (madhatter@tomcruz.net) .  I don't respond well to reports about my stupidity 
or comments such as "why reinvent the wheel".  If you aint figured it out,  you never will. 

The code below was written in C++ with the borland builder 5.0 . 

CODE  -  update Nov / 15 / 2003 

Source Code 

The datalink is very functional but I am sure it still has a crash or two left in it. 
The problematic code is in the GUI code. I have not found it necessary to edit the 
engine in quite a while. though I have not edited much of the code at all in a while either. 
(Still in developement)   Ver. 0.1.6 build 13   updated 2/20/05; 

DownLoad the Datalink 

The  DLL is being rewritten. New stuff soon 
 

******************************************************************** 
Progress not perfection   ;-) 

note - January/02/2006/11.03pm , I havent been doing to much thes few months.
but I do have some sql functionality. The parsing engine is a bitch. I can do
the select stuff as well as some search functions from sql. I have also done
the code to go to and from csv file format. This will open up the file format
for wider usage, as I am no longer restricted to the mtb format. I dont know know
if I will do any other file formats as yet. For what I am intending, I would think that
the cvs funtion is adequate for importing and exporting.

note - july/12/2005/9.48pm , I have started a rewrite of the dll. the 
direction I was going in was not very comfortable and I guess I understand 
the process a little more now. 

note - july/3/2005/10.04pm , I now have a working SQL engine.  It is 
not very complete but it is working and is creating a result set for 
one field. 

note - feb/20/2005/9.49pm , Search functions are working and I am doing 
some work on the restructure methods. 

note - Jan/01/2005/9.30pm , New version posted that addresses some major bugs 
that were present in the new table function and processing. 

note - august/31/2004/11:41pm , I have returned to the code after some five or six months 
attending to my wifes illness.  I remedied many of the bugs that were frustrating me then. 
It would seem I only needed a break.  I have some work to do on the create table function, 
in the GUI.  But the project as a whole is working.  By the way, the Table generator is 
renamed to Datalink. 

note - Jan/18/2.23am , The documentaion is coming along slowly. The Dll has made a progression 
to another version. As well as the table generator. Bugs, Bugs, Bugs. 

note - dec/5/11.28pm , I think that I am ready for some documentation to accompany the project. 
I am presently working on an html howto manual. 

note - dec/3/10.00pm , Please update your copy of the Table Generator if you have version 0.0.3 
or earlier.   The restructure function is now working adequately. 

note - nov/23/11.00pm , I am concentrating on the restructure function of the Table Generator. 
This will allow the user to change or edit the table as they please.  The methods developed for 
the Table Generator will find their way into the database engine as coded methods to restructure 
the the table directly from the MHDBE. 

note - nov/23/7.23pm , Please update your copy of the Table Generator if you have version 0.0.1 . 
the version 0.0.2 that is posted now has fixed a bug on the post function. 

note - nov/21/4.38pm , The table Generator  is being developed primarily to test the table access and 
manipulation of the table properties.  During the developement of this progrm I realized that it would 
be useful as a utility to accompany the database engine.  Also the MHDBE DLL is very stable and is 
posted as well.  I do need to write a howto text or html file to accompany the downloads.  this will 
be posted as soon as possible. 

note - nov/15/2:15am ,  When I translated the TString objects to a vector I missed some items in 
the create table function.  I have been working on this for half a day and I feel like a dunce.  The new 
code is posted. 

note - nov/15/12:24am , An error has crept into the create table function.  I havent used it in a week 
or so.  I have been utilizing table files created previously and I havent kept up with this function.  I have 
to back track a bit to find the error. 

note - nov/12/10:00pm , The files are separating into the subsets.  I have a working version of a DLL. 
The records vector is not exported due to some process I dont fully understand as yet.  I have a work 
around in place until I can solve the problem. 

note - nov/08/8:45pm ,  I just got rid of the TSringlist objects and utilized a vector for the list objects. 
I seem to have shaved 20 milliseconds off the load time for the above file.  I'll post the new code in a day 
or so.  The code is now independant of the VCL library. 
 
note - nov/02/10:30pm ,   Just some performance parameters for opening the table. 
   3546 records Size (741,376 bytes) 
   load table avg 116 MSec (nonvisual) 
   load table avg 1010 MSec (visual - string grid) 
   platform win98, 128mb ram, 450mz amd processor 

note - oct/26/6:30pm , The flogging has gone well and the code below has survived after an allnight run. 
During this process the test platform generated a file of 3249 records.  The test platform is a while loop 
that randomly selects the next, prior, post and delete methods of the table class. 

note - oct/22/6:30pm , The flogging has uncovered an error in the code..  It seems to add a lot of blank 
records to the file.  I am presently working on this, so dont look for an update on the code for a couple of 
weeks. 

note - oct/19 1am , going on to 300,000 iterations with no exceptions.  When I get to a million I'll clean up 
the code and post it.  1 million without the gui and am flogging the gui now.  The present code will load 
1700 records (418kb) in under 2 seconds on an AMD 450 with 128 mb ram. 

note - oct/18/03 , I have begun to flog the core using a 10000 iteration while loop.  At present the 
exception count is about 20 or so.  The exceptions are occuring with the delete and the post function. 
My goal is for an all nighter with no exceptions.  The public functions of the table class are selected at 
random as well as the fiields  being randomly loaded.  The core is quite useable at this time but needs 
a lot of testing. 

note - oct/12/03 
The division of labor has begun.  Below is the core of the engine as I see it.  I have begun to separate 
the engine from the visual operations such as displaying the edits, listboxes, stringgrids and such. 
I will post the visual header later as it develops.