Assigned to me filtration of workflow on Purchase Oder Form

public void executeQuery()
{


 QueryBuildRange         rangeCompanyId;
    QueryBuildRange         rangeUserId;
    QueryBuildRange         rangeId;
    QueryBuildRange         rangeStatus;
 Query query;
 QueryBuildDatasource    datasource;
 WorkflowWorkItemTable   workflowWorkItemTable;
 QueryBuildDataSource    qbdsWorkFlowItemTable;
;


 if(Filter.valueStr() == "Assigned To Me" )
                    {

query = new Query();
                 
                    datasource = query.addDataSource(tableNum(PurchTable));

                    // Add child datasource "WorkflowWorkItemTable" to previously created DS
                    qbdsWorkFlowItemTable = datasource.addDataSource(tableNum(WorkflowWorkItemTable));

                    // Set the join mode
                    qbdsWorkFlowItemTable.joinMode(JoinMode::ExistsJoin);

                 
                    qbdsWorkFlowItemTable.relations(true);

                 
                    qbdsWorkFlowItemTable.addLink(fieldNum(PurchTable, RecId),
                    fieldNum(WorkflowWorkItemTable, RefRecId));

                    qbdsWorkFlowItemTable.addLink(fieldNum(PurchTable, TableId),
                    fieldNum(WorkflowWorkItemTable, RefTableId));
                    rangeStatus = qbdsWorkFlowItemTable.addRange(fieldnum(WorkflowWorkItemTable, Status));
                    rangeStatus.value(queryValue(WorkflowWorkItemStatus::Pending));
                    rangeStatus.status(RangeStatus::Locked);
                    rangeCompanyId = qbdsWorkFlowItemTable.addRange(fieldnum(WorkflowWorkItemTable, CompanyId));
                    rangeCompanyId.value(queryValue(curext()));
                    rangeCompanyId.status(RangeStatus::Locked);

                    rangeUserId = qbdsWorkFlowItemTable.addRange(fieldnum(WorkflowWorkItemTable, UserId));
                    rangeUserId.value(queryValue(curuserid()));
                    rangeUserId.status(RangeStatus::Locked);

                    //The Id-range is only used to lock the query from the Ui
                    rangeId = datasource.addRange(fieldnum(WorkflowWorkItemTable, Id));
                    rangeId.status(RangeStatus::Locked);
                    rangeId.enabled(false);
                    // info(query.dataSourceNo(1).toString());
                    this.query(query);
}
}