Implement a function to connect to a DB

Major paradigm shift in ADO .NET is to disconnected dadtasets -- you connect, grab the data and disconnect. Gone are the days of persistent connections.

I'm using  VB 2005

ok, the days of persistent connections are over.
how can I implement a public function that I could can on any form I have in my project.
Actually I'm trying to implement a function that would execute all my SQL queries, such as insert, delete and update.


public function ADO_Execute (byval strQuery as string) as Boolean
on error goto err_handler
Execute strQuery
ADO_Execute=true
exit function
Err_handler:
ADO_Execute=false
end function
 thanks for the help

The equivalent code with VB.NET would be something like (coded onto the screen, so not tested)

public function ADO_Execute (byval strQuery as string) as Boolean
Dim result As Boolean = True
Try
   myCommand.CommandText = strQuery
   myConnection.Open
   myCommand.ExecuteNonQuery
Catch
   result = False
   'some error reporting here if you want it
Finally
   If myConnection.State = ConnectionState.Open Then
       myConnection.Close
End Try
Return result
end function

That assumes that there is some declaration and initiation, with scope accessible to this function, of (a) an OleDbConnection and (b) and OleDbCommand - with the OleDbConnection as its .Connection property.

But - while there is no rule against executing your insert, delete and update piecemeal, with a function such as this -the disconnected approach of the ADO.NET model offers other possibilities.  Such as saving them all up (automatically) in the datatable and using a dataadapter to do them all at once.

Roger

Sancler,

This is what happens while I'm driving home LOL

The one scenario you didn't cover (which my original code does, so maybe we can forgive you) is the SELECT statement :)

Chaosian

ok, actually I'm kind of new with VB.Net. Can you tell me to implement this function do I have to create a new class just for the functions cause I have to implement more public functions, and be specific on the select statement implementation.
thanks

It depends how "pure" you want to be.  The main alternatives are a Class or a Module.  The former is more consistent with the object-oriented approach, the latter is (in my view) slightly easier to code.

Whichever you choose, it sounds as though you want to put all your data objects (dataset/datatable/s, connection, command, dataadapter) and methods (such as the function you proposed) in it.  Then, if you use a Class, you can expose public properties and methods to return such objects/information as you wish to other parts of your app or, if you use a Module, you can just call (and refer to) its public methods and objects from any other part of your app.

For specifics on the select statement implementation, this is a good site for connection strings

   http://www.connectionstrings.com/

You would want the appropriate one from under the heading "OLE DB, OleDbConnection (.NET)".

The query string would be in standard sql format - like

   "SELECT * FROM MyTable"

or

   "SELECT ThisField, ThatField FROM MyTable WHERE ThisField < 100"

Roger