Once you've got a
connection to the database, you can then send commands to it. The OleDbCommand
object allows you to send commands to the database. You enter a SQL statement
and depending on how you execute it (it has several execute commands) it can
do almost anything with the data.
objCmd as New OleDbCommand("SELECT * From users", objConn)
As you can see, its
simple, it takes in a SQL String and the name of a connection object to use.
You can also do it this way -
objCmd as New OleDbCommand()
objCmd.Connection = objConn
objCmd.CommandText = "SELECT * FROM users"
could even do it like this -
Dim objCmd as New OleDbCommand(SQL String, connection string)
We won't worry about
these, they do exactly the same thing with the last one you provide a
connection string instead of a connection object.
At this stage, we haven't executed the statement yet and there are numerous
ways to do this.
This is the way you execute when the string
isn't going to return any data, like an INSERT or UPDATE SQL string.
It does its job and that's it.
If you've got a data reader (explained later,
then you can use this to put the data into a data reader -
objRd as OleDbDataReader
objRd = objCmd.ExeuteReader
Use the ExecuteScalar method to retrieve a
single value (for example, an aggregate value) from a database.
I've been using the OleDbCommand to insert things into a database, it's quite