refresh, reread, research and executeQuery
RefreshThis method basically refreshes the data displayed in the form controls with whatever is stored in the form cache for that particular datasource record. Calling refresh() method will NOT reread the record from the database. So if changes happened to the record in another process, these will not be shown after executing refresh().
refreshExThis method should be used sparingly, in cases where multiple rows from the grid are updated, resulting in changes in their display Options, as an example. So you should avoid using it as a replacement for refresh(), since they actually have completely different implementations in the kernel.
RereadCalling reread() will query the database and re-read the current record contents into the datasource form cache. This will not display the changes on the form until a redraw of the grid contents happens
ResearchCalling research() will rerun the existing form query against the database, therefore updating the list with new/removed records as well as updating all existing rows. This will honor any existing filters and sorting on the form, that were set by the user.
ExecuteQueryCalling executeQuery() will also rerun the query and update/add/delete the rows in the grid. The difference in behavior from research is described below.
ExecuteQuery should be used if you have modified the query in your code and need to refresh the form to display the data based on the updated query.