Usually, after a record is being deleted, it will be stored in the recycle bin for 15 days. These records are being recognised by a checkbox field called IsDeleted. When a record is being deleted, this checkbox will automatically be checked.
Question: Can we update the IsDeleted checkbox to True?
Apparently, this checkbox is made READ ONLY. So how can we restore records from the recycle bin?
WARNING: You will not be able to restore any records if they are being HARD DELETED.
Method #1: Manual restore
If you only have a few data, suggest that you restore them manually. Simple go to Home -> Recycle Bin, select the records that you would like to restore and click on ‘Undlete’ button.
* Once records are restored, any child tied to these records will also be restored.
Method #2: Developer Console
You can try running a few lines of codes in the developer console. Depending on the scenario, you can program the code to restore based on different condition.
For example: Restore all Account where Isdeleted = TRUE and Created Date = TODAY().
Method #3: Re-importing deleted records
You can use Apex Data Loader to export all deleted data and re-import them. Apex Data Loader ‘Export All’ allows you to export ALL data including any soft deleted data (in recycle bin).
*This will not restore any child records as this method is as if you are re-importing all the data from scratch.*
Method #4: Workbench
You can also try Salesforce Workbench where it can query all deleted records and undelete them straight from Workbench.