Android Room @Delete with parameters

Question

I know I can\'t use DELETE in a query (that is a shame by the way), I will get the following error:

Error:error: Observable query retur         


        

Answer 1

You can use below method to delete by ID

@Query("DELETE FROM yourDB WHERE id = :id")
void deleteById(int id);

for delete all rows

@Query("DELETE FROM yourDB")
void delete();

Answer 2

The beauty of room is, we play with the objects. As per requirement you can use for kotlin:

@Delete
fun delete(model: LanguageModel)

for Java:

@Delete
void delete(LanguageModel model)

it will delete the exact object which is stored in the db with the same values. LanguageModel is my model class and it works perfectly.

Answer 3

Actually, you can use @Query to perform a delete.

@Query("DELETE FROM users WHERE user_id = :userId")
abstract void deleteByUserId(long userId);

Extracted from Query javadoc:

UPDATE or DELETE queries can return void or int. If it is an int, the value is the number of rows affected by this query.