Bug 199021 Error message pops up several times when click an invalid dataset
Description: There is a sqlserver datasource and dataset, remove the jtds driver to let the dataset invalid. Double click on the dataset, the error message will pop up serveral times. Build version:2.2.0.v20070807-0630 Steps to reproduce: 1. Create a sqlserver datasource and dataset. 2. Remove the jtds driver, and the dataset will be invalid. 3. Double click on the dataset. Expect result: Error message pops up once to indicate the problem. Actual result: Error message pops up serveral times.
data/org.eclipse.birt.report.data.oda.jdbc.ui/src/org/eclipse/birt/report/data/oda/jdbc/ui/editors/SQLDataSetEditorPage.java
{
					try
					{
						meta = this.metaDataProvider.getConnection( )
								.prepareStatement( this.getDataSetDesign( )
										.getQueryText( ) )
								.executeQuery( )
								.getMetaData( );
					}
					catch ( Exception ex )
					{
						meta = null;
					}
				}
				if ( meta == null )
					return;
				
				if ( this.getDataSetDesign( ).getPrimaryResultSet( ) == null )
				{
					this.shouldUpdateDataSetDesign = true;
					return;
				}
				
				ResultSetColumns rsc = this.getDataSetDesign( ).getPrimaryResultSet( ).getResultSetColumns( );
				if( meta.getColumnCount( )!= rsc.getResultColumnDefinitions( ).size( ))
				{
					this.shouldUpdateDataSetDesign = true;
					return;
				}