We model these cars as, as shown here in Showroom’s implementation (along with the Car definition): // Showroom class public class Showroom. Some cars may be brand new, while others are secondhand. We can represent this with a simple model.Įvery showroom will have a variety of cars to sell. A showroom consists of dozens of cars for customers to view and possibly purchase. How can we persist our cars list using Hibernate? To get a better understanding, let’s see an example.Ĭonsider a simple case of a car showroom.

It will then associate and map these items together to find out the order, and accordingly feed the client with the ordered responses.īut enough theory. So, when it fetches the cars from the main table, it also fetches the indexed order of these items from the additional table (called, say, CAR_LIST). To satisfy this requirement, Hibernate maintains another table with the cars’ indexes.

So, if we run a query list.get(n), we should get back the nth element without fail. We should expect to retrieve the car data from the table in the same order in which it was inserted. We can insert an element anywhere in the list, and retrieve the element using its index.įor example, let’s say we have persisted a list of manufacturers (Toyota, BMW, Mercedes, etc.) via our Java program. They can also keep track of an element’s position, using indexes. Lists are simple and easy data structures to hold items in an orderly manner. In fact, it goes one step further and creates a couple of other collections, such as bag and idbag. The familiar Java collections-such as List, Set, Array, and Map-are all supported by Hibernate.

We need to follow certain mapping procedures and processes to let Hibernate know our intentions.

Persisting simple values from Hibernate’s view is different from persisting collection elements such as or structures. We will, at some point, encounter persistent objects with collections as their values. Java collections are the most common data structures in Java, with various algorithm features. We will look in detail at how we can persist the standard Java collections using the Hibernate framework.Īs a Java developer, at some point in your programming life, you have probably worked with Java collections. In this chapter, we will learn about Hibernate’s support for persisting and retrieving collections. Working with data structures, formally known as Java collections, is inevitable for any Java developer.

Hibernate persistence example