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SqlCeCommand.SetRange Method

Restricts the set of rows that will be read by the SqlCeDataReader.

Namespace:  System.Data.SqlServerCe
Assembly:  System.Data.SqlServerCe (in System.Data.SqlServerCe.dll)

public void SetRange(
	DbRangeOptions dbRangeOptions,
	Object[] startData,
	Object[] endData
)

Parameters

dbRangeOptions
Type: System.Data.SqlServerCe.DbRangeOptions
The options used when specifying the range.
startData
Type: System.Object[]
The starting key values for the range.
endData
Type: System.Object[]
The ending key values for the range.

ExceptionCondition
InvalidOperationException

IndexName property has not been set.

This method is intended to be a faster alternative to a SELECT statement for retrieving a set of rows from a base table. Instead of a WHERE clause in a SELECT statement, SetRange can be used to quickly retrieve a set of rows based on their index values. For example, to retrieve a set of employees with an employee ID between 1 and 5, you could execute a SELECT statement, but setting a range of 1 to 5 on the employee ID index will greatly improve performance.

This method can only be used when CommandType is set to TableDirect, CommandText is set to a valid base table name, and IndexName is set to a valid index name on the specified base table. When SetRange is used, the SqlCeDataReader returned from ExecuteReader will only return rows whose key values in the specified index match the range.

When Seek is used on a SqlCeDataReader that has a range, Seek will only position on rows in the specified range. For detailed information about SetRange, see the "IRowsetIndex::SetRange" topic in the OLE DB documentation.

This example retrieves data from the Orders table using an index into a SqlCeDataReader. The range on the index on which to Seek is specified by the SetRange method.

        try
        {
            SqlCeConnection conn = new SqlCeConnection("Data Source = MyDatabase.sdf");
            conn.Open();

            SqlCeCommand cmd = conn.CreateCommand();
            cmd.CommandType = CommandType.TableDirect;
            cmd.IndexName = "Orders_PK";
            cmd.CommandText = "Orders";

            // We are interested in orders that match Order ID = 10020
            //
            cmd.SetRange(DbRangeOptions.Match, new object[] { 10020 }, null);

            SqlCeDataReader reader = cmd.ExecuteReader(CommandBehavior.Default);

            for (int i = 1; reader.Read(); i++)
            {
                MessageBox.Show(String.Format("{0} ; {1}", reader["Order ID"], reader["Order Date"]));
            }

            // Now we are interested in orders with Order ID between (10020, 10050)
            //
            cmd.SetRange(DbRangeOptions.InclusiveStart | DbRangeOptions.InclusiveEnd,
                new object[] { 10020 }, new object[] { 10050 });

            reader = cmd.ExecuteReader(CommandBehavior.Default);

            // Now seek to Order ID = 10045
            //
            bool onRow = reader.Seek(DbSeekOptions.FirstEqual, new object[] { 10045 });

            // Now ,the reader will return rows with Order ID >= 10045 <= 10050
            // because the range was set to (10020, 10050)
            //
            if (onRow)
            {
				for (int i = 1; reader.Read(); i++)
				{
					MessageBox.Show(String.Format("{0} ; {1}", reader["Order ID"], reader["Order Date"]));
				}
            }
        }
        catch (Exception e)
        {
            MessageBox.Show(e.Message);
        }


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