one to many

Author: Nikita Konev

readme.md

@@ -1 +1,3 @@
-Adapted example from [here](https://javabydeveloper.com/spring-data-jdbc-many-to-many-example/)
+Intro https://spring.io/blog/2018/09/17/introducing-spring-data-jdbc
+Adapted example from [here](https://javabydeveloper.com/spring-data-jdbc-many-to-many-example/)
+Many-To-many https://spring.io/blog/2018/09/24/spring-data-jdbc-references-and-aggregates

src/main/kotlin/com/example/web/jdbc/web/jdbc/Application.kt

@@ -20,7 +20,8 @@ fun main(args: Array<String>) {
 class AppRunner(
         private val subjectRepository: SubjectRepository,
         private val branchRepository: BranchRepository,
-        private val personRepository: PersonRepository
+        private val personRepository: PersonRepository,
+        private val orderRepository: OrderRepository,
 ) : ApplicationRunner {
 
     private val logger = LoggerFactory.getLogger(this::class.java)
@@ -65,8 +66,13 @@ class AppRunner(
         val allSubjects = subjectRepository.findAll()
         allSubjects.forEach { logger.info("Found subject {}", it) }
 
+
         // https://docs.spring.io/spring-data/jdbc/docs/current/reference/html/#jdbc.query-methods
         val foundPersons = personRepository.findByLastName("Doe", PageRequest.of(1, 10))
         foundPersons.forEach { logger.info("Found Person {}", it) }
+
+        // https://spring.io/blog/2018/09/24/spring-data-jdbc-references-and-aggregates
+        val orders = orderRepository.findAll();
+        orders.forEach { logger.info("Found order {}", it) }
     }
 }

src/main/kotlin/com/example/web/jdbc/web/jdbc/Entities.kt

@@ -28,4 +28,21 @@ data class Branch(
 
 data class BranchData(val buildingType: String?, var rating: Int, var comment: String?)
 
-data class Person (val id: Long, var firstName: String, var lastName: String)
+data class Person (val id: Long, var firstName: String, var lastName: String)
+
+data class OrderItem (
+    var quantity: Int = 0,
+    var product: String
+)
+
+data class PurchaseOrder (
+    @Id
+    val id: Long,
+    var shippingAddress: String,
+    @MappedCollection(idColumn = "purchase_order_id")
+    val items: MutableSet<OrderItem> = HashSet()
+) {
+    fun addItem(quantity: Int, product: String) {
+        items.add(OrderItem(quantity, product))
+    }
+}

src/main/kotlin/com/example/web/jdbc/web/jdbc/Repositories.kt

@@ -2,6 +2,7 @@ package com.example.web.jdbc.web.jdbc
 
 import org.springframework.data.domain.Page
 import org.springframework.data.domain.Pageable
+import org.springframework.data.jdbc.repository.query.Query
 import org.springframework.data.repository.CrudRepository
 import org.springframework.stereotype.Repository
 
@@ -15,4 +16,9 @@ interface BranchRepository : CrudRepository<Branch, Int>
 @Repository
 interface PersonRepository : CrudRepository<Person, Long> {
     fun findByLastName(lastname: String, pageable: Pageable) : Page<Person>
+}
+
+interface OrderRepository : CrudRepository<PurchaseOrder, Long> {
+    @Query("select count(*) from order_item")
+    fun countItems(): Int
 }

src/main/resources/db/changelog.yml

@@ -22,4 +22,10 @@ databaseChangeLog:
       author: nkonev
       changes:
         - sqlFile:
-            path: /db/changelog/1648633720__person_doe.sql
+            path: /db/changelog/1648633720__person_doe.sql
+  - changeSet:
+      id: 5
+      author: nkonev
+      changes:
+        - sqlFile:
+            path: /db/changelog/1648636121__order.sql

src/main/resources/db/changelog/1648636121__order.sql

@@ -0,0 +1,19 @@
+CREATE TABLE purchase_order(
+    id BIGSERIAL PRIMARY KEY,
+    shipping_address TEXT NOT NULL
+);
+CREATE TABLE order_item(
+    order_item_id BIGSERIAL PRIMARY KEY,
+    purchase_order_id BIGINT REFERENCES purchase_order(id),
+    quantity INT NOT NULL,
+    product TEXT NOT NULL
+);
+
+INSERT INTO purchase_order (shipping_address) values
+('Tbilisi'), -- 1
+('Moscow'); -- 2
+
+INSERT INTO order_item(purchase_order_id, quantity, product) VALUES
+(1, 100, 'Tea'), -- 1
+(1, 200, 'Coffee'), -- 2
+(1, 2, 'Bread'); -- 3