asked on

Open database at runtime

My database is in my app.exe folder (and I want my app. to allways look for it there and display error otherwise).
Also I need to tell my app that the table to open is in that database.How?
What is the code supposed to look like?

Russell Libby

What kind of database are you using (pdox, access, dbase, etc)?

Russell

Vrtnar

ASKER

I am using absolute database (*.abs)

TheRealLoki

well.. assuming you are using a TDataset descendent such as TTable then you would do

table1.databasename := ExtractFilePath(Paramstr(0)); // same dir as .exe

if you want to do a search in the current dir and find the files yourself, you can do this :-

procedure TForm1.Button1Click(Sender: TObject);
var
searchrec: tsearchrec;
databasefiles: tstringlist;
searchresult: integer;
begin
databasefiles := TStringList.Create;
try
searchresult := findfirst(extractfilepath(paramstr(0)) + '*.abs', faAnyFile, SearchRec);
while searchresult = 0 do
begin
if pos('.', SearchRec.Name) <> 1 then
databasefiles.Add(SearchRec.Name);
searchresult := FindNext(SearchRec);
end;
memo1.lines.assign(databasefiles); // show the list of databse files in a memo
finally
databasefiles.Clear;
databasefiles.Free;
end;
end;

TheRealLoki

if you have 1 database file (file.abs) you can do a simple check like

if FileExists(ExtractFilePath(Paramstr(0)) + 'file.abs') then
showmessage('file is here, i can continue')
else
raise exception.create('file.abs does not exist');

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Russell Libby

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Vrtnar

ASKER

procedure TForm1.FormCreate(Sender: TObject);
var
DataBaseName,DatabaseFileName: string;
begin
Path := ExtractFilePath(Application.ExeName);
DatabaseName:= ExtractFilePath(ParamStr(0)) + 'Mydatabase.abs';

should go something like that...?

Vrtnar

ASKER

ExcludeTrailingbackslash is specific to a platform ?!

Russell Libby

Nope, included in sysutils and my personal coding preference;

szDbFile:=ExcludeTrailingbackslash(ExtractFilePath(Application.ExeName))+'\'+DbFile;

(notice i include the '\' between the path and file name). You can change it to the following if it suits you:

szDbFile:=ExtractFilePath(Application.ExeName)+DbFile;

---
Russell

Vrtnar

ASKER

well libby,i did your suggestion and it worked.what i do not understand is the
szDbFile thing.

SOLUTION

TheRealLoki

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Russell Libby

The szDbFile "thing" is the Application's path PLUS the database file name which are used to build an absolute file name. The only change required in the example I gave was the 2 constansts: database name and table name.

Russell

Vrtnar

ASKER

Loki :

procedure TForm1.FormCreate(Sender: TObject);
var
DataBaseName, DatabaseFileName: string;
begin
DatabaseName := 'Mydatabase';
DatabaseFileName:= ExtractFilePath(ParamStr(0)) + Mydatabase.abs';
if not FileExists() then Raise Exception.Create('File does not exist' + #13#10 + DatabaseFileName);
end else
ABSDatabase1.DatabaseName:= DatabaseName; ABSDatabase1.DatabaseFileName:=DatabaseFileName;
ABSDatabase1.Open;
ABSTable1.DatabaseName:= DatabaseName;
ABSTable1.TableName:= 'Mytable';
ABSTable1.Open;
end;
I get stopped here : if not FileExists() then
[Error] Unit1.pas(234): Not enough actual parameters

Russell Libby

if not FileExists(DatabaseFileName) then Raise Exception.Create('File does not exist' + #13#10 + DatabaseFileName);
end else