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Finishing the Daos4:17 with Ben Deitch
In this video we'll create Daos for our Pizza and PizzaTopping tables!
Did you figure it out? 0:00 No worries if you didn't, 0:02 we'll work through it anyway starting with the PizzaDao. 0:03 First, we create a new interface and the data package. 0:06 Named PizzaDao. 0:12 Then we make it official by adding the @Dao annotation 0:16 Inside the Dao, we'll create a query to select all the pizzas, @Query. 0:24 Select * from pizza. 0:32 Then we'll declare a function called getAll to go with our query. 0:36 And, it'll return all list of pizzas. 0:43 Moving on to selecting a specific pizza, we'll create the query. 0:47 Which is select * from 0:54 pizza where id = :id. 0:58 Then we're at the function, which is fun getPizzaById with 1:03 an id parameter that returns a pizza object. 1:11 Next we've got the Insert statement. 1:15 So let's add the Insert annotation. 1:18 Along with the insert function, fun insert and it should take in a pizza. 1:21 Finally, we need a query to delete a pizza based on an ID. 1:27 There is actually an @Delete annotation, but it only works with pizza objects. 1:32 So if we want to delete something by an ID, we'll have to use a query. 1:38 Let's add a query annotation. 1:43 And then for the query itself, 1:46 let's go with delete from pizza where id = :id. 1:51 Then let's add the function, which should take a none Id and 1:58 return nothing, fun delete pizza 2:03 by Id which takes a none Id and returns nothing, awesome! 2:08 Now, let's move on to the pizza toppingDao. 2:14 Let's create another new interface. 2:17 Called PizzaToppingDao. 2:21 Then let's add the @Dao annotation. 2:27 And let's add a query to give us which topping IDs go with a certain pizza ID. 2:31 @Query, and then select toppingId from 2:35 pizzatopping where pizzaId = :id. 2:43 And let's also create the function for that. 2:50 Fun ToppingIdsForPizzaId, and 2:55 we'll pass in an ID which is an integer. 3:00 And we'll be returning a list of topping IDs, which is a list of integers. 3:09 Moving on to the insert statement, let's add the @Insert annotation followed 3:16 by the insert function, fun insert and it takes in the pizzaTopping object. 3:22 And last but not least, 3:29 what's @Query to remove rose associated with a specific pizza ID. 3:31 Let's start with a query notation and then the query, 3:37 delete from pizzatopping where pizzaId = :id. 3:42 Then adding the function, fun deletePizzaById 3:48 which takes an (id:int) and returns nothing. 3:53 Alright, that wraps up creating our Daos. 3:59 Let's think back to our data model and see what we need to make next. 4:02 We've got the entities and we've got the data access objects. 4:06 So it must be time to create the room database to tie it all together. 4:10 We'll do that in the next video. 4:14
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