DELETE Operation

DbQuery is using SQLiteDatabase.delete() in the back. However, the API wraps and add more stuffs to the interface.

The following code does the same thing - removing computer from Products table.

numDeleted = db.get("Products")
                    .delete(productId)
                    .query();
...
numDeleted = db.get("Products")
                    .delete("Name = ?", "Computer")
                    .query();
...

Note that query() is called to get the numDeleted. If you don't care about the returned value, you may not call query() at all.

#Bulk-deletion Using Id. The following code does the same thing - deleting multiple products using their Id

long[] idsToRemove = ...
numDeleted = db.get("Products")
                    .delete(idsToRemove)
                    .query();
...
List<Long> idListToRemove = ...
numDeleted = db.get("Products")
                    .delete(idListToRemove)
                    .query();
...
// using varargs...
numDeleted = db.get("Products")
                    .delete(1,2,3,5,6,7,...)
                    .query();

Note that query() is called to get the numDeleted. If you don't care about the returned value, you may not call query() at all.

#Bulk-Deletion using a condition The following code shows bulk-deletion using some condition - we're deleting any product whose name starts with "Key" (will include: "Keychain", "Keyboard", "Key"....)

...
numDeleted = db.get("Products")
                    .delete("Name LIKE ?", "Key%")
                    .query();
...

Note that query() is called to get the numDeleted. If you don't care about the returned value, you may not call query() at all.

#Using IEntity Calling delete(IEntity) is equivalent to calling delete(IEntity.getId())

// assuming you have Product class which implements IEntity
public class Product implements IEntity {
   ...
}
...

// somewhere else in the code
Product product = new Product();
product.setId(someId);
...
numDeleted = db.get("Product")
                  .delete(product)
                  .query();
assertTrue(numDeleted == 1); // one product gets deleted

Note that query() is called to get the numDeleted. If you don't care about the returned value, you may not call query() at all.

#Using IEntityList Calling delete(IEntityList<IEntity>) is equivalent to calling delete(int...) which is bulk-deletion

// assuming you have `ProductList` which implements `IEntityList<Product>`
public class ProductList extends ArrayList<Product> implements IEntityList<Product>{
   ...
}
...

// somewhere in the code
ProductList productList = new ProductList();
productList.add(productA);
productList.add(productB);
...
numDeleted = db.get("Products")
                 .delete(productList)
                 .query();
assertTrue(numDeleted == productList.size());

Note that query() is called to get the numDeleted. If you don't care about the returned value, you may not call query() at all.