Bug 153853 [Regression]The bound column names must be unique within the entire table.
Regression case Regression_136421(under org.eclipse.birt.report.tests.model) failed. Expected result: Model will avoid adding a duplicate bound column name within a table.
model/org.eclipse.birt.report.model/src/org/eclipse/birt/report/model/api/ModuleHandle.java
}
	/**
	 * Returns the system id of the module. It is the URL path of the module.
	 * 
	 * @return the system id of the module
	 */
	public URL getSystemId( )
	{
		return module.getSystemId( );
	}
	/**
	 * Removes special script lib.
	 * 
	 * @param scriptLib
	 *            script lib
	 * @throws SemanticException
	 */
	public void dropScriptLib( ScriptLib scriptLib ) throws SemanticException
	{
		ElementPropertyDefn propDefn = module.getPropertyDefn( SCRIPTLIBS_PROP );
		if ( scriptLib == null )
			return;
		PropertyCommand cmd = new PropertyCommand( getModule( ), getElement( ) );
		cmd.removeItem( new CachedMemberRef( propDefn ), scriptLib );
	}
	/**
	 * Removes all script libs.
	 * 
	 * @throws SemanticException
	 */