Tue, 25 Aug 1998 03:00:00 GMT

Autoinc paradox fields - programmatic creation - HELP

sim...@magicnet.net (Frank Postava) wrote thusly:

Quote
>Hey Delphites....
>Using the example for the CreateTable method of the TTable component, I
>can't figure out how to create an autoincrement paradox field.  When a
>table is opened, the FieldDef.Datatype for an autoinc field is ftInteger.
> Using ftInteger to create simply makes an Integer field!
>Nay Ideas????
>Thanks In Advance
>Frank...

I had the same question last month and the answer I got from Michael
Salem (a nice fellow across the pond in merry old England) quoted me
section 6 of the Delphi FAQ that answers this specific question.  The
following expands on that and shows how to also create a memo field
and detect an existing data base.

{}PROCEDURE   TCreate.Build_DB_AddrBook;
{+O
---------------------------------------------------------------------------
  Purpose     - Create programmatically the AddrBook database and
indexes.
  Revised     - 1996.0306 (KSB) Wrote initial version.
---------------------------------------------------------------------------}
  VAR
    lw        : WORD;
  BEGIN
    WITH query1 DO BEGIN
      DatabaseName := 'ADDRESSES';      {alias}
      WITH SQL DO BEGIN
        Clear;                          {create a paradox table (thus
the .DB extension)}
        Add('CREATE TABLE "ADDRBOOL.DB" (');
        Add('UniqueKey AUTOINC,');      {use an autoincrement key}
        Add('LastName CHAR(80),');
        Add('FirstName CHAR(30),');
        Add('MiddleName CHAR(30),');
        Add('Title CHAR(80),');
        Add('ThePosition CHAR(80),');   {"Position" is a SQL keyword,
thus "ThePosition" - Delphi's SQL burps otherwise}
<snip - other fields - snip>    
        Add('EntryDate DATE,');
        Add('Notes BLOB(240),');
          {a blob is recognized as a Paradox memo.
           the BLOB(240) specifies that 240 characters
           of the memo are to be stored in the DB file,
           the remainder if any to be stored in the MB file.}
        Add('PRIMARY KEY(UniqueKey))');
        TRY
          ExecSQL;                        {Execute the SQL statement}
        EXCEPT
{
  If the database already exists the errorCount is 2 with the
following values:
    category      51
    errorcode  13057
    subcode        1
    nativecode     0
    message  [0]   "File already exists."
             [1]   name_and_path_of_file

Quote
}

          ON E:EDBEngineError DO BEGIN
            lw := E.errorCount;
            FOR lw := 0 TO E.errorCount-1 DO BEGIN
              WITH E.errors[lw] DO BEGIN
                MessageDlg('AddrBook Creation error:'#$0D
                 +' category:'+IntToStr(category)+#$0D
                 +' code:'+IntToStr(errorCode)+#$0D
                 +' subCode:'+IntToStr(subCode)+#$0D
                 +' nativeCode: '+IntToStr(nativeError)+#$0D
                 +message,
                mtWarning,[mbOk,mbCancel],0);
              END {WITH};
            END {FOR};
          END {ON};
        END {TRY};

        Clear;
        Add('CREATE INDEX NameAsKey ON "ADDRBOOL.DB" (LastName,
FirstName, MiddleName, Organization)');
        ExecSQL;
        Clear;
<snip - removed code for other secondary indexes -snip>
      END {WITH};
    END {WITH};
{}END {Build_DB_AddrBook};

Good Luck.
Keith S. Brown
Information Technology Office
NASA/JSC - Houston