Re: adodb

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Most of the answers provided are available in your VB Help.

> and what is ADODB?
Microsoft ADO (ActiveX Data Objects) is a Component object model object for
accessing data sources. It provides a layer between programming languages
and databases, which allows a developer to write programs which access data,
without knowing how the database is implemented. No knowledge of SQL is
required to access a database when using ADO, although one can use ADO to
execute arbitrary SQL commands. The disadvantage of this is that this
introduces a dependency upon the database.
en.wikipedia.org/wiki/ADO


>also, why does this peice of code insist on me
> providing a startup object?
Not sure... You should have a startup object. You can use either a Form or a
"Sub Main()" procedure. You would use a Form if you want the user of the
program to enter directly into a Menu, for example. You would use a Sub
Main() to set values of certain variables, controls, etc... prior to opening
a Form. If you use the Sub Main() you will need to open a Form through code
inside the Sub in order for the user to ever see anything.

> Dim adoConnection As ADODB.Connection
A Connection object represents a unique session with a data source. In the
case of a client/server database system, it may be equivalent to an actual
network Connection to the server. Depending on the functionality supported
by the provider, some collections, methods, or properties of a Connection
object may not be available.

You establish the Connection object to "Connect" to the database (i.e. Your
Modem would be your connection object to dial-up to your ISP).

> Dim adoRecordset As ADODB.Recordset
A Recordset object represents the entire set of records from a base table
or the results of an executed command. At any time, the Recordset object
refers to only a single record within the set as the current record.

> Dim connectString As String
This is a variable declaration. The variable name is "connectString". A
String variable is used to hold a group of alphanumeric characters.
Generally names, codes, etc...

> Set adoConnection = New ADODB.Connection
Here you are allocating the "adoConnection" object for a New connection to
the database.
Example: Here you are telling your Modem to connect to the Verizon Server

> Set adoRecordset = New ADODB.Recordset
Same thing here except this is a Recordset.

> connectString = "Provider=Microsoft.Jet.OLEDB.4.0;" _
> & "Data Source=C:\Documents and Settings\Iqbal\My
> Documents\IQBAL\test.mdb"
The connection string is telling the program what you are connecting to,
where the database is, and what options you want to use for the connection.
In the above line you are connecting to Microsoft Access and your database
is located in the IQBAL folder in your My Documents.

> adoConnection.Open connectString
This is telling the program to connect now, using the connection string
provided. (i.e. Clicking the "Dial" button on your connection to your ISP.

> adoRecordset.Open "Table1", adoConnection
This is setting your Recordset to all the data in your "Table1" table using
the open connection to the database "adoConnection".

> Do Until adoRecordset.EOF
>
> List1.AddItem adoRecordset!UserName
> adoRecordset.MoveNext
> Loop

The above code snippet is a Do Until...Loop (similar to a For...Next Loop).
This will iterate through all the records in your recordset. Each one that
it finds it is adding the UserName fields data to a ListBox, "List1". The
EOF is End of File. This tells the the Loop that you are at the end of the
Recordset's data collection. The MoveNext method tells the loop to move to
the next record in the Recordset at each iteration of the loop.

> adoRecordset.Close
> adoConnection.Close
The above lines are closing the Recordset and Connection to the Database.
(i.e. Disconnecting from your ISP to go offline.) NOTE: The data that you
retrieved from the Database will still be loaded into your ListBox.

> Set adoRecordset = Nothing
> Set adoConnection = Nothing
Here you are deallocating the Recordset and Connection objects. (i.e.
Freeing up your RAM)

Here is a Tutorial download for ADO:
http://www.planet-source-code.com/vb/scripts/ShowCode.asp?txtCodeId=12050&ln
gWId=1

Hope this helps...

Branden Johnson


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