Example of accessing ADO.Net

Code: 
Dim oConnection As New SqlConnection
Dim oCommand As New SqlCommand
Dim oDataReader As SqlDataReader

oConnection.ConnectionString = "user id=;password=;database=;server=;Connect Timeout=15"
oConnection.Open()

oCommand.Connection = oConnection
oCommand.CommandText = "SELECT * FROM myTable"

oDataReader = oCommand.ExecuteReader()

While oDataReader.Read()
    Loop though data
End While

oDataReader.Close()
oConnection.Close()
 
EOF: SqlDataReader.Read = False
BOF: No equivalent and no need for one. Its the beginning if you havent called .Read yet.
Field collection: Item Collection
 
Is ther any property that allows me to know if a connection object is closed (i.e. VB6 = if recordset.state = adstateopen then
 
the SQLConnection object has a state property.


Code: 
dim conn as System.Data.SqlClient.SQLConnection

if conn.State = ConnectionState.Closed Connection closed

end if
 
Can we open new reader while i doing loop of 1 reader?
example :

oDataReader = oCommand.ExecuteReader()

While oDataReader.Read()
Loop though data
At there contain read to other sql statement to retrieve info
End While
 
hi possiblydamp,

just a little bit confused as to checking the connection state using
the code
dim conn as System.Data.SqlClient.SQLConnection

if conn.State = ConnectionState.Closed Connection closed

end if


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as you stated above. i think this will check the connection state.
how exactly can i do it for a datset? like we do for recordset. is there any method.

also while searching in recordset using find command we can know the cursor position in the recordset.

in dataset.table.Select we can search the fields but can we get the location where the search stopped ?

help.
 
Hi Guys, Im just doing a bit of research towards moving across to VB.Net and was wondering why you would use this method as opposed to using a SqlDataAdapter, which would utilize a disconnected SqlConnection. What are the advantages / disadvantages of each method.

Thanks
 
A datareader is a forward only read of data...very fast but only reads doesnt allow for dataset manipulation.
"Adapters are used to exchange data between a data source and a dataset.
In many applications, this means reading data from a database into a dataset,
and then writing changed data from the dataset back to the database. However,
a data adapter can move data between any source and a dataset. For example,
there could be an adapter that moves data between a Microsoft Exchange server and a dataset." (From the search of "Visual Basic and Visual C# Concepts")
 
Thanks for your help on tha above questions it was really informative. Just one more question. In n-tier applications that I previously developed, I often used recordsets to pass data back and forth across different tiers. How does this work in regards to DataAdapters and DataReaders.
 
Depends on how your going to implement the app. If youre serving up data across a large network,
the best way is asp.net. Uses the same disconnected dataset and all the work is done on the server.
No worries about cursors, the adapter takes care of that for you.
That what youre concerned about?
 
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