76.4 Creating the Data Access Object

With the product entity defined, the next step is to create the DAO interface. Referring once again to the Project tool window, right-click on the app -> java -> com.ebookfrenzy.roomdemo entry and select the New -> Kotlin File/Class menu option. In the new class dialog, enter ProductDao into the Name field and select Interface from the list as highlighted in Figure 76-1:

Figure 76-1

Click on OK to generate the new interface and, with the ProductDao.kt file loaded into the code editor, make the following changes:

package com.ebookfrenzy.roomdemo

 

import androidx.lifecycle.LiveData

import androidx.room.Dao

import androidx.room.Insert

import androidx.room.Query

 

@Dao

interface ProductDao {

 

    @Insert

    fun insertProduct(product: Product)

 

    @Query("SELECT * FROM products WHERE productName = :name...