Board index » delphi » Creating and Access DB on-the-fly

Michael R. Simpson

Delphi Developer
Mon, 24 Jul 2000 03:00:00 GMT

Creating and Access DB on-the-fly

I'm trying to re-program a Visual Basic application to Dephi 3.  In my VB
application, I create an Access DB with three tables using the DAO (jet)
object.  I did it this way so that I could update the program without
having to provide blank database and tables created externally.

Is there anyway I can do this using Delphi 3 and the BDE.  Visual basic is
such a Walrus for my application.  The mscomm component can't even keep up
with a 4800 baud NMEA 0183 serial data stream, and that's before my program
processes the data.

I know how to manipulate an existing Access database, but not how to create
one in code.  Any help greatly appreaciated.

        Mike Simpson

 
Jody Snowdo

Delphi Developer
Tue, 25 Jul 2000 03:00:00 GMT

Re:Creating and Access DB on-the-fly


Quote
Michael R. Simpson wrote:

> I'm trying to re-program a Visual Basic application to Dephi 3.  In my VB
> application, I create an Access DB with three tables using the DAO (jet)
> object.  I did it this way so that I could update the program without
> having to provide blank database and tables created externally.

> Is there anyway I can do this using Delphi 3 and the BDE.  Visual basic is
> such a Walrus for my application.  The mscomm component can't even keep up
> with a 4800 baud NMEA 0183 serial data stream, and that's before my program
> processes the data.

> I know how to manipulate an existing Access database, but not how to create
> one in code.  Any help greatly appreaciated.

>         Mike Simpson

Have a look at the Delphi Local SQL help namely CREATE TABLE, ALTER
TABLE, data manipulation stuff.  Also have a look at the same statements
in the Access help as the SQL statements have to be syntactically
correct for Access.  Something like the following will make you a table
in access
CREATE TABLE NewTable
                (FieldOne TEXT, FieldTwo TEXT,
                 ,...., FieldN DATATYPE);

Also need to add index and key information into the definition but this
is all pretty well documented.  Hope this helps.

Jody.

Bill Todd (Tea

Delphi Developer
Tue, 25 Jul 2000 03:00:00 GMT

Re:Creating and Access DB on-the-fly


I got this code from another user but I have not tested it.

...............cut here ......................
const
  dbLangGeneral = $0409; {default language, English and related}

  {version and encryption options}
  dbVersion10 = 1;
  dbEncrypt = 2;
  dbDecrypt = 4; {only used when packing}
  dbVersion11 = 8;
  dbVersion20 = 16;
  dbVersion30 = 32; {choose this for Access 95 database}

procedure CreateJetDatabase(const FileName: string;
  Locale: integer; options: integer);
var
  DBEngine: Variant;
  Workspace: Variant;
begin
  DBEngine := CreateOleObject('DAO.DBEngine');
  Workspace := DBEngine.Workspaces[0];
  Workspace.CreateDatabase(Filename, $409, Options);
end;

Bill

(Sorry but TeamB cannot answer support questions received via email.)
(To send me email for any other reason remove .nospam from my address.)

Brian Bushay Tea

Delphi Developer
Tue, 25 Jul 2000 03:00:00 GMT

Re:Creating and Access DB on-the-fly


Quote
>I'm trying to re-program a Visual Basic application to Dephi 3.  In my VB
>application, I create an Access DB with three tables using the DAO (jet)
>object.  I did it this way so that I could update the program without
>having to provide blank database and tables created externally.

>Is there anyway I can do this using Delphi 3 and the BDE.

If you are looking  to create a .mdb file you can do it.  Sample code
follows.  Tables can be created in Delphi with CreateTable and with
SQL

.................
const
  dbLangGeneral = ';LANGID=0x0409;CP=1252;COUNTRY=0';

  {version and encryption options}
  dbVersion10 = 1;
  dbEncrypt = 2;
  dbDecrypt = 4; {only used when packing}
  dbVersion11 = 8;
  dbVersion20 = 16;
  dbVersion30 = 32; {choose this for Access 95 database}

procedure CreateJetDatabase(const FileName: string;
  Locale: String; options: integer);
var
  DBEngine: Variant;
  Workspace: Variant;
begin
  DBEngine := CreateOleObject('DAO.DBEngine');
  Workspace := DBEngine.Workspaces[0];
  Workspace.CreateDatabase(Filename, locale, Options);
end;

procedure TForm1.Button1Click(Sender: TObject);
begin
CreateJetDatabase('blip3.mdb',dblangGeneral,dbEncrypt )
end;

--
Brian Bushay (TeamB)
Bbus...@DataGuidance.com

Michael Simpso

Delphi Developer
Wed, 26 Jul 2000 03:00:00 GMT

Re:Creating and Access DB on-the-fly


Brian Bushay TeamB <BBus...@DataGuidance.com> wrote in article
<34e78d72.38835...@forums.borland.com>...

Quote

> procedure CreateJetDatabase(const FileName: string;
>   Locale: String; options: integer);
> var
>   DBEngine: Variant;
>   Workspace: Variant;
> begin
>   DBEngine := CreateOleObject('DAO.DBEngine');
>   Workspace := DBEngine.Workspaces[0];
>   Workspace.CreateDatabase(Filename, locale, Options);
> end;

Brian:  
Thanks for the reply (as well as the other responders to my plea for help).
 I tried the above code ( with JET DAO 3.5) and got an Ole error when
creating the OLE object.  Upon examining the registry I found a
'DAO.DBEngine.35' label and when I substituted it for the DAO.DBEngine
param, my program made more progress.  It then crashed at the
CreateDatabase line with an error: "Unable to find installable ISAM".
Since the Access .MDB database file is not part of the ISAM file list, I
have to assume that the JET object is mixed up about the creation of the
desired database type.  The workspase and createdatabase calls are similar
to those I used in VB, so the culprit is probably the CreateOleObject code
but I'm not sure why.  I have both VB 5.0 and Access 97 on my computer and
they are properly registered.  Any further help appreciated..

                Michael Simpson

Michael Simpso

Delphi Developer
Wed, 26 Jul 2000 03:00:00 GMT

Re:Creating and Access DB on-the-fly


Bill Todd (TeamB) <Bill_T...@compuserve.com.nospam> wrote in article
<34da7ed6.16237...@forums.borland.com>...

Quote
> procedure CreateJetDatabase(const FileName: string;
>   Locale: integer; options: integer);
> var
>   DBEngine: Variant;
>   Workspace: Variant;
> begin
>   DBEngine := CreateOleObject('DAO.DBEngine');
>   Workspace := DBEngine.Workspaces[0];
>   Workspace.CreateDatabase(Filename, $409, Options);
> end;

Bill:
Thanks for the reply (as well as the other responders to my plea for help).
 I tried the above code ( with JET DAO 3.5) and got an Ole error when
creating the OLE object.  Upon examining the registry I found a CLSID
'DAO.DBEngine.35' label and when I substituted it for the DAO.DBEngine
param, my program made more progress.  It then crashed at the
CreateDatabase line with an error: "Unable to find installable ISAM".
Since the Access .MDB database an installable ISAM, I
have to assume that the JET object is mixed up about the creation of the
desired database type.  The workspase and createdatabase calls are similar
to those I used in VB, so the culprit is probably the CreateOleObject code
but I'm not sure why.  I have both VB 5.0 and Access 97 on my computer and
they are properly registered.  Any further help appreciated..

                Michael Simpson

Brian Bushay Tea

Delphi Developer
Thu, 27 Jul 2000 03:00:00 GMT

Re:Creating and Access DB on-the-fly


Quote
>he workspase and createdatabase calls are similar
>to those I used in VB, so the culprit is probably the CreateOleObject code
>but I'm not sure why.  I have both VB 5.0 and Access 97 on my computer and
>they are properly registered.  Any further help appreciated..

The CreateOleObject needs ComObj in the USES of the unit where you use
it.  Beyond that all I can tell you is I have personaly tested the
code and it works for me.  I have Access97 installed on my machine.

--
Brian Bushay (TeamB)
Bbus...@DataGuidance.com

Michael Simpso

Delphi Developer
Thu, 27 Jul 2000 03:00:00 GMT

Re:Creating and Access DB on-the-fly


Brian Bushay TeamB <BBus...@DataGuidance.com> wrote in article
<34dd1070.37425...@forums.borland.com>...

Quote

> The CreateOleObject needs ComObj in the USES of the unit where you use
> it.  Beyond that all I can tell you is I have personaly tested the
> code and it works for me.  I have Access97 installed on my machine.

Thanks for the Reply Brian.  I'm stumped! Yes I had the USES ComObj ,  I've
tried the program on both my work and home computers (200 MMX win95
machines) and on both machines I get a raised exception 'Ole error
80040112' when I hit the CreateOleObject line of code.  I Don't know what
that error number references?

                Michael Simpson

Michael Simpso

Delphi Developer
Thu, 27 Jul 2000 03:00:00 GMT

Re:Creating and Access DB on-the-fly


Brian Bushay TeamB <BBus...@DataGuidance.com> wrote in article
<34dd1070.37425...@forums.borland.com>..

.

Quote
> The CreateOleObject needs ComObj in the USES of the unit where you use
> it.  Beyond that all I can tell you is I have personaly tested the
> code and it works for me.  I have Access97 installed on my machine.

Whoa!  I Tried your code (with the full Lang specifier: dbLangGeneral =
';LANGID=0x0409;CP=1252;COUNTRY=0';) using DBEngine := CreateOleObject
('DAO.DBEngine.35'); and it WORKED:  I thought I had tried that combo but
apparantly not.  Thanks a lot.  (for some reason it still does not work
using the 'DAO.DBEngine' CLSID.

                        Thanks much
                                Michael Simpson

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