Oracle Database Interaction Using ODP.NET and ASP.NET: All Ways to Retrieve Data Continued - Making an offline cache using “OracleDataAdapter”
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Even though, the above method works well, it has its own drawbacks. If we have 10,000 rows, for example, it takes a long time to fill with all the rows (even though it is sometimes unnecessary). With the “OracleDataAdapter” object, it just fetches based on the “fetchsize” property dynamically, only when necessary. The following example illustrates this:
Dim cn As New OracleConnection("User
ID=scott;password=tiger;Data Source=ORCL")
Try
Dim da As New OracleDataAdapter("select * from
scott.emp", cn)
Dim dt As New DataTable
da.Fill(dt)
da.Dispose()
Me.DataGrid1.DataSource = dt
Me.DataGrid1.DataBind()
dt.Dispose()
Catch ex As Exception
Me.lblError.Text = ex.Message
Finally
If cn.State = ConnectionState.Open Then
cn.Close()
End If
End Try
The main statements from the above code fragment are only the following:
Dim da As New OracleDataAdapter("select * from scott.emp", cn)
Dim dt As New DataTable
da.Fill(dt)
da.Dispose()
The above makes all the rows (based on the built-in “fetchsize” property) offline with only four lines. This method is quite simple and quite efficient when compared with the previous method, and is very suitable to work in production scenarios.
Next: Parameterized queries using “OracleDataAdapter” >>
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