An OracleCommandBuilder object provides automatic SQL generation for the OracleDataAdapter when updates are made to the database.

Class Inheritance

System.Object

  System.MarshalByRefObject

    System.ComponentModel.Component

      System.Data.Common.DbCommandBuilder

        OracleDataAccess.Client.OracleCommandBuilder

Declaration

// C#
public sealed class OracleCommandBuilder : DbCommandBuilder

Requirements

Thread Safety

All public static methods are thread-safe, although instance methods do not guarantee thread safety.

Remarks

OracleCommandBuilder automatically generates SQL statements for single-table updates when the SelectCommand property of the OracleDataAdapter is set. An exception is thrown if the DataSet contains multiple tables. The OracleCommandBuilder registers itself as a listener for RowUpdating events whenever its DataAdapter property is set. Only one OracleDataAdapter object and one OracleCommandBuilder object can be associated with each other at one time.

To generate INSERT, UPDATE, or DELETE statements, the OracleCommandBuilder uses ExtendedProperties within the DataSet to retrieve a required set of metadata. If the SelectCommand is changed after the metadata is retrieved (for example, after the first update), the RefreshSchema method should be called to update the metadata.

OracleCommandBuilder first looks for the metadata from the ExtendedProperties of the DataSet; if the metadata is not available, OracleCommandBuilder uses the SelectCommand property of the OracleDataAdapter to retrieve the metadata.

Example

The following example performs an update on the EMP table. It uses the OracleCommandBuilder object to create the UpdateCommand for the OracleDataAdapter object when OracleDataAdapter.Update() is called.

// C#
 
using System;
using System.Data;
using Oracle.DataAccess.Client;
 
class OracleCommandBuilderSample
{
  static void Main()
  {
    string constr = "User Id=scott;Password=tiger;Data Source=oracle";
    string cmdstr = "SELECT empno, sal from emp";
 
    // Create the adapter with the selectCommand txt and the
    // connection string
    OracleDataAdapter adapter = new OracleDataAdapter(cmdstr, constr);
 
    // Create the builder for the adapter to automatically generate
    // the Command when needed
    OracleCommandBuilder builder = new OracleCommandBuilder(adapter);
 
    // Create and fill the DataSet using the EMP
    DataSet dataset = new DataSet();
    adapter.Fill(dataset, "EMP");
 
    // Get the EMP table from the dataset
    DataTable table = dataset.Tables["EMP"];
 
    // Indicate DataColumn EMPNO is unique
    // This is required by the OracleCommandBuilder to update the EMP table
    table.Columns["EMPNO"].Unique = true;
 
    // Get the first row from the EMP table
    DataRow row = table.Rows[0];
 
    // Update the salary
    double sal = double.Parse(row["SAL"].ToString());
    row["SAL"] = sal + .01;
 
    // Now update the EMP using the adapter
    // The OracleCommandBuilder will create the UpdateCommand for the
    // adapter to update the EMP table
    adapter.Update(dataset, "EMP");
 
    Console.WriteLine("Row updated successfully");
  }
}