Differences among reread(), refresh(),research() datasource methods in dynamics ax 2009.

Commonly after opened the form we need to do some operations with existing data. In few cases we need to interact with data base again and again in order to do. For that we will use these methods. But so many developers are confusing to use these methods.

refresh() : this method will refresh the data in the data source cache. But it will not interact with the data base to fetch the new/updated record values. Whatever values have fetched in the previous query will store in data source cache, this method will just refresh the data source cache only.

reread(): this method will interact with the data base and runs the query against the data base in order to fetch the new/updated record values. But this will not show the updated values in the form until calling the refresh method. That means it will update the data source form cache only but not existing form control values.
So it is better to call the methods as shown here, like reread and after refresh methods in order to fetch the new / updated values from the data base.

formDataSource.reread()
formDataSource.refresh()

research():Calling 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.