JPA-从数据库查找表加载静态数据的最佳实践是什么？

Question

I have a lookup table in my relational database schema called UserRole where it has the following table columns:

Role_Id | Role_Name | Role_Desc | (some other foreign key ids linking to other tables) |
-------------------------------------------------------------------------------
1       | Admin     | Admin user| ......                                               | 

All rows in above table are static data (they never ever change in my application)

At the moment i have an Entity persistent object:

@Entity
@Table(name = "UserRole")
public class RoleEntity {

@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
@Column(name = "Role_Id")
private int id;

@Column(name = "Role_Name")
private String role_name;

@Column(name = "Role_Desc")
private String role_desc;
....

// other code omitted for brevity
}

I have an equivalent Repository class which just fetches the data: for eg

entityManager.find(...).getResultsList() etc...

................................................................

Every time when i need to use these roles i am making a call to the database directly. I feel there is no need for this because the data never change in my case. I thought of storing the data in an Enum instead and not have that data in the database but the data is already part of a legacy system and i can't change the database design plus that table already has many links to other tables.

I want to load them only once maybe at startup.

What is the best way to do this?

Is it simply just have like a singleton class to maintain a (static?) list of all the roles, and after initialising, use the Repository class to make a call to Database to fetch the data into the list in memory.?

Answer 1

What worked for this particular problem is what OndrejM suggested. It as simply as creating a singleton bean and store results of my query upon startup. And of course, there is no pattern or official way to do it. That is the answer.