I have two entities
#Entity
public class Module {
#Id
#GeneratedValue(strategy = GenerationType.AUTO)
private Integer id;
private String name;
private String descr;
#OneToMany(cascade = {CascadeType.ALL})
#JoinColumn(name="ID", referencedColumnName="ID")
private List<Permissions> perms;
}
#Entity
public class Permissions {
#Id
#GeneratedValue(strategy = GenerationType.AUTO)
private Integer id;
private Integer clientId;
private String role;
private Character endorseCreate;
private Character endorseUpdate;
private Character endorseDelete;
private Character endorseView;
I am trying to fetch data by first Module.name and Permissions.clientId and Permissions.role
Something like in sql
select * from Module m, Permissions p where m.id=p.id and p.clientId=1 and p.role='ADMIN'
How can I achieve using JPA, I am using spring data aswell.
Can a method be declared in CRUD Repo provided by spring data?
I think the issue is I am unable to find way to pass values to fetch data.
Any help is greatly appreciated
Related
I'm coding a CRUD JPA web application. My goal is that a given parent Vehicle can only have a single child Driver, but during runtime this same Driver can instead be assigned to another Vehicle and vice versa. To my understanding, this could be accomplished via an OneToOne relationship.
I've tried some different approaches, but to no success. I can assign a Vehicle to a Driver just fine, but when I try to update/create a new Vehicle and give him a Driver, via controllers, nothing happens. I can only do it the other way around. I'm assuming this is because Vehicle is the parent and I can only create a new relation by updating a parent.
My question is, is it possible to make these updates bidirectional and how can I achieve that?
I've tried using a shared primary key, using a foreign key, using a join table. The result is always the same and I can't quite grasp why. I have an OneToMany relationship working on this application and it works as I expect it to work. I can update on one side or the other, delete on one side or the other. Both entities have been updated. OneToOne? Parent seems to have all the power.
This is what I'm working with right now:
Driver
#Entity
#Table(name= "drivers")
public class Driver {
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
private int id;
#Column(nullable = false)
private String name;
#Column(nullable = false)
private int age;
#OneToOne(mappedBy = "driver")
private Vehicle vehicle;
Vehicle
#Entity
#Table(name= "vehicles")
public class Vehicle {
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
private int id;
#Column(nullable = false)
private String make;
#Column(nullable = false)
private String model;
#Column(nullable = false)
private int mileage;
#Column(nullable = false)
private int year;
#Column(nullable = false)
private int fuel;
#OneToOne
#JoinColumn(name = "driver_id")
private Driver driver;
And just for reference, this is the OneToMany relationship I have and that I'm happy with. I'd like my OneToOne to have the same behavior, except I don't need to save a list of entities, only one.
#Entity
#Table(name="stops")
public class Stop {
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
private int id;
#Column(nullable = false)
private String name;
#ManyToOne
#JoinColumn(name="route_id")
private Route route;
#Entity
#Table(name="routes")
public class Route {
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
private int id;
#Column(nullable = false)
private String name;
#OneToMany
#JoinColumn(name = "route_id")
private List<Stop> stops = new ArrayList<>();
Any tips would be appreciated, thank you for your time.
I want to join column without object reference. is that possible?
I want to do foreign key without object reference like that
#Data
#Entity
#Table(name = "HRM_EMPLOYEE_SALARY_INCREMENT")
public class EmployeeSalaryIncrement implements Serializable {
private static final long serialVersionUID = 9132875688068247271L;
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
#Column(name="ID")
private Integer id;
#Column(name = "REFERENCE_NO")
private String referenceNo;
#ManyToOne
#JoinColumn(name = "AUTHORITY", referencedColumnName = "id")
private Integer authority;
#ManyToOne
#JoinColumn(name = "PART_TWO_REGISTER_ID")
private Integer partTwoRegisterId;
#Column(name = "PART_TWO_ORDER_NO")
private String partTwoOrderNo;
#Column(name = "REMARKS")
private String remarks;
#Column(name = "HRM_TYPE")
private Integer hrmType;
}
If I found solve this problem, it will helpful for me.
Joining is not needed in this case. If you only need the foreign key value, then simply add the column as a #Column like any other:
#Data
#Entity
#Table(name = "HRM_EMPLOYEE_SALARY_INCREMENT")
public class EmployeeSalaryIncrement implements Serializable {
private static final long serialVersionUID = 9132875688068247271L;
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
#Column(name="ID")
private Integer id;
#Column(name = "AUTHORITY")
private Integer authority;
// other fields
// ...
}
No, I don't think that you can join columns between two entities without adding the reference of one to the related entity. You will have to create one entity class corresponding to each of your relational database table and add the reference of one to the other to establish relation.
However, I understand that you may not need all the attributes from your related table based upon your use case, and only wish to select one column from it. You can do that either by only adding required attributes in your joined table entity class (if you are sure you won't need other attributes for that table anywhere else).
Or you can use custom queries using JPQL in your repository class which selects only the required attributes from the tables that you have joined.
I will show you an example of the second way:
//Say, this is your entity class where you wish to join other table to fetch only one attribute from the joined table-
#Entity
#Table(name = "TABLE1", schema = "SCHEMA1")
public class Table1 {
#Id
#Column(name = "ID")
private String id;
#Column(name = "TABLE2_COLUMN")
private String table2Column;
#ManyToOne(fetch = FetchType.EAGER)
#JoinColumn(name = "TABLE2_COLUMN1")
private Table2 table2; //refrence of the joined table entity object
}
// And this is the joined table entity class
#Entity
#Table(name = "TABLE2", schema = "SCHEMA1")
public class Table2 {
#Id
#Column(name = "ID")
private String id;
#Column(name = "TABLE2_COLUMN1")
private String table2Column1;
#Column(name = "TABLE2_COLUMN2")
private String table2Column2; // The column which we want to select from the joined table
}
In your repository class -
#Repository
public interface Table1Repository extends JpaRepository<Table1, String> {
#Query("SELECT t1 FROM Table1 t1 WHERE t1.id = :id")
public List<Table1> getTable1Rows(#Param("id") String id);
#Query("SELECT t1.table2.table2Column2 FROM Table1 t1 WHERE t1.id = :id")
public String getTable2Column2(#Param("id") String id);
}
Based upon the response from Markus Pscheidt below, I agree when he said there's no need to join the entities if you only need the attribute which is a foreign key. As foreign key is already present as an attribute in your entity (or table) you are working with.
If you need to fetch any other column apart from foreign key, then you may use JPQL to fetch the exact column that you wish to select.
I wonder what database structure would be the best option in my case:
I have entity Questionnaire:
#Table(name = "questionnaire")
public class Questionnaire extends BaseEntity {
private static final long serialVersionUID = 1L;
#Id
#GeneratedValue(strategy = GenerationType.AUTO)
private Long id;
#OneToMany(mappedBy = "fieldStatus")
private List<QuestionnaireField > fieldStatusList;
}
#Table(name = "questionnaire_field")
public class QuestionnaireField extends BaseEntity {
private static final long serialVersionUID = 1L;
#Id
#GeneratedValue(strategy = GenerationType.AUTO)
private Long id;
#Column(name = "questionnaire_id")
private Long questionnaireId;
#Column(name = "field_id")
private Long fieldId; //this is id related to the other table Field
#Column(name = "completed")
private boolean completed; //because I need some additional informations like completed I think I can't use ManyToMany between Questionnaire and Field
#ManyToOne(cascade = {CascadeType.PERSIST, CascadeType.REMOVE})
#JoinColumn(name = "questionnaire_id")
private Questionnaire questionnaire;
As you see each Questionnaire can have multiple QuestionnaireFields, BUT each QuestionnaireField is of type Field (hence I added private Long fieldId). Table Field can have 10.000 different fields.
Summary:
one questionnaire can have e.g. 10 Fields, the second one 20 another Fields etc. To store fields related to some particular Questionnaire I created QuestionnaireField table with 2 columns: private Long questionnaireId; and private Long fieldId; . The question is if it is a good approach? That are plain columns not related to any Foreign Key... I try to find the best solution to save Questionnaire with related QuestionnaireFields that are a subset of a big Field table...
I have several similar tables in DB.
Now I use for each table own Model and Repository
But I think, this is not right decision.
Can I make a one Model and Repository for all similar tables?
#Entity
#Table(name = "BEDROOM", schema = "public")
public class BedroomModel extends AllFinishProductModel{
#Column(name = "PHOTO")
private String photo;
#Id
#Column(name = "ID")
#GeneratedValue(strategy=GenerationType.IDENTITY)
private Long id;
#Column
private String name;
#Column(name = "DESCRIPTION")
private String description;
#Column(name = "STRUCTURE") //organza, curtain ....
private String structure;
#Column(name = "PAINT") //abstraction, geometric ....
private String paint;
#Column(name = "HEIGHT")
private String height;
#Column(name = "COLOR")
private String color;
#Column(name = "QUANTITY")
private Double quantity;
#Column(name = "PRICE")
private BigDecimal price;
#Column(name = "SEWED")
private String itIsSewed;
... getters and setters
}
I have a similar tables: CABINET, GUESTROOM, CHILDREN_ROOM, KITCHEN, CURTAIN and TULLE.
Which code should be used for repository?
I tried to find answers to the questions inhttps://docs.spring.io/spring-data/data-commons/docs/1.6.1.RELEASE/reference/html/repositories.html
But I don't find answers here.
Can you give advice, how to make it or link?
You can use entity inheritance with #MappedSuperclass annotation on parent class to get common properties in child classes/tables.
So, for example you have a parent Room entity with common properties, which you annotate with #MappedSuperclass.
#MappedSuperclass
public class Room {
#Column
private String name;
#Column(name = "DESCRIPTION")
private String description;
// some more common properties
}
And concrete rooms, e.g.:
#Entity
public class Bedroom extends Room
{
// common properties will be inherited
private Bed bed;
private NightLamp nightLamp;
}
Now, the important part is that Room is not mapped as any table. The room is a "virtual" table, which doesn't exist in the db. Only concrete entities exist as tables, like Bedroom.
Here you have the link to the official javadoc:
http://docs.oracle.com/javaee/5/api/javax/persistence/MappedSuperclass.html
I am developing web application using spring and hibernate. I am using one to one mapping between two tables employee and PersonelDetails.
below are my bean classes
=======================Employee=====================================
#Entity
#Table(name="employee")
public class Employee {
#Id
#Column
#GeneratedValue
private int empid;
#Column
private String firstName;
#Column
private String lastName;
#Column
private String email;
#Column
private String password;
#Column
private boolean isAdmin;
#Column
private boolean isActive;
#Column
private boolean isLocked;
//getter setters
====================PersonalDetails class====================
#Entity
#Table(name="PersonalDetails")
public class PersonalDetails {
#Column
#Id
private int empid;
#Column
private String personalEmail;
#Column
private String mob;
#Column
private String permenantAdress;
#Column
private String currentAddress;
#Column
private String gender;
#Column
private String maritialStatus;
#MapsId
#OneToOne(cascade = CascadeType.ALL)
#JoinColumn(name = "empid", referencedColumnName = "empid")
#ForeignKey(name="empid")
private Employee employee;
//getter setters
In my application table employee is filled by Admin user while creating new employee after that employyee himself fill personalDetails table by login to his accountCreated by Admin)
Now when I try to send personal details bean to hibernate layer first I have to get the employee bean from employee table then call setEmployee method over personalDetails class and save employee bean in personalDetails and send to hibernate layer for saving in database.
So while getting employee bean from database and again send back through personalDetails bean leads to a performance issue.
Can anyone help here to clarify while saving data in child table(PersonalDetails) is it really mandatory to pass parent object(Employee) ?
=======================code to store personalDetails===============
#RequestMapping(value="addpersonal")
public ModelAndView addPersonalDetails(#ModelAttribute("personalDetails") PersonalDetails personalDetails) {
//personalDetails.setEmpid(1);
personalDetails.setCurrentAddress("niljyoti");
personalDetails.setMob("9405715872");
personalDetails.setPermenantAdress("address");
Employee e = empService.getEmployeebyUserName(uname);
personalDetails.setEmployee(e);
personalDetailsService.addPersonalDetails(personalDetails);
return new ModelAndView("home");
}
On read:
You can change fetch strategy if you are worried.
Based od JPA spec, default fetch type for #OneToOne is EAGER.
By setting fetch = FetchType.LAZY, instead of real PersonalDetails object, an object of a subclass behaving as a proxy is returned. Hence, selecting from employee table starts only after getEmployee is called.
On write:
You need to specify connection between entities, in your model, the only way is the employee field. However, you can specify mappedBy, see answer to this question:
Java: Hibernate #OneToOne mapping