Mamouri
asked on
Connecting new component to multiple Databases!
Hi
I'm working on a helper component for database programs. This component
derived from TComponent and connect to a TTreeView and load a tree structure
into TTreeView. I want my component could work with multiple Databases like
ADO, BDE, Interbase, DBISAM, etc.
What's the best solution for that? If I set my connection property to
TADOConnection then my component could not work with Paradox. If I set my
connection property as TCustomConnection, in the component I want to create
a DataSet and connect to database. then I don't know to create with kind of
DataSet? TADOTable, TTable, TIBTable, TDBISAMTable?
Does somebody know a good soltution?
Regards
I'm working on a helper component for database programs. This component
derived from TComponent and connect to a TTreeView and load a tree structure
into TTreeView. I want my component could work with multiple Databases like
ADO, BDE, Interbase, DBISAM, etc.
What's the best solution for that? If I set my connection property to
TADOConnection then my component could not work with Paradox. If I set my
connection property as TCustomConnection, in the component I want to create
a DataSet and connect to database. then I don't know to create with kind of
DataSet? TADOTable, TTable, TIBTable, TDBISAMTable?
Does somebody know a good soltution?
Regards
SOLUTION
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atul_parmar
Sorry for my BAD english.
ASKER
I could not get your idea completely. do you know a component that used such idea for connectivity?
I agree with atul_parmer, try to keep it abstract at the TTreeview level, and use "TDataset".
and when you need to talk to the treeview do something like this
procedure DoTreeViewThing(dataset: TDataset);
...
if "using paradox table" then
DoTreeViewThing( TDataset(Table1) ) // might be (Table1 AS TDataset) ... I forget which :-)
else if "using ado table" then
DoTreeViewThing( TDataset(ADOTable1) )
... etc
procedure MyComponent.DoTreeViewThin
begin
for i := 0 to pred(dataset.fields.count)
...
newtreenode.caption := dataset.Fields[0].AsString
end;
and when you need to talk to the treeview do something like this
procedure DoTreeViewThing(dataset: TDataset);
...
if "using paradox table" then
DoTreeViewThing( TDataset(Table1) ) // might be (Table1 AS TDataset) ... I forget which :-)
else if "using ado table" then
DoTreeViewThing( TDataset(ADOTable1) )
... etc
procedure MyComponent.DoTreeViewThin
begin
for i := 0 to pred(dataset.fields.count)
...
newtreenode.caption := dataset.Fields[0].AsString
end;
ASKER
Thank you parmar and TheRealLoki!
Any other idea?
Any other idea?
ASKER CERTIFIED SOLUTION
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ASKER
In fact user must only specify the connection. the component itself must create required TTable or TADOTable or TDBISAMTable and work with these components.
Regads
Regads
ASKER
I must mention the component I'm workin on is not a general component for every projects. This component will use only on one project.
It seems that you didn't get it clearly. Your component will have a property say Dataset and the user will assign the TDataset compitible component to your propert what may be TTable or TADOTable or TDBISAMTable.
so user will create a connection and a table and assign it to your dataset property.
e.g. YourComponent.Dataset := Table1;
so user will create a connection and a table and assign it to your dataset property.
e.g. YourComponent.Dataset := Table1;
Even if it is not generic component, the above said practice is highly flexible and preferable.