How many types of delete actions are there? Explain each of them with example

4 types:
None- If any record is deleted from the main table and there is a record the child table, than it will not be deleted.
Cascade- Deletes the corresponding record in the linked table based on the relational key columns
Restricted- Doesn't allow us to delete the record in the main table and says "The record may not be deleted. Transactions exist in table 'Child'".
Cascade + Restricted-If we do deletions from X++ it is treated as restricted, where as if we do deletion from Form it is treated as the cascade.