I have been trying to fetch data from 2 different tables to a single entity in JPA but with no result.
The entity that keeps data from two different tables is as below :
#Data #Entity #JsonSnakeCase
public class WareHouse {
#Id
#GeneratedValue
private long id;
#Column(unique = true)
private String fcId;
#Enumerated(EnumType.STRING)
private FCStatus status;
#OneToMany(cascade = CascadeType.PERSIST, fetch = FetchType.EAGER, mappedBy = "fcId")
private List<WorkingHours> workingHours;
#Enumerated(EnumType.STRING)
private IntegrationType integrationType;
}
The other entity WorkingHours is :
#Data
#Entity
#JsonSnakeCase
public class WorkingHours {
#Id
#GeneratedValue
private long id;
private String fcId;
private LocalDate date;
private DateTime start;
private DateTime end;
}
The tables WareHouse and WorkingHours have one-to-many relationship and fcId is the column that joins them.
In my use case, I have to fetch WareHouse details and its WorkingHours in a single entity WareHouse as defined above. How do I achieve this ?
The named query (below) only fetches the WareHouse data and WorkingHours is coming empty. Is the data model wrong ? Or is the query wrong ? (I thought JPA would take care of automatically fetching from the related table when given the annotations OneToMany and FetchType etc.)
<named-query name="searchByFcId">
<query>
<![CDATA[
select f from WareHouse f where f.fcId = :fc_id
]]>
</query>
</named-query>
You can try the following mappings. The JPA 2.0 spec note (11.1.21) notes:
If the referencedColumnName element is missing, the foreign key is assumed to
refer to the primary key of the referenced table.
However it also goes on to note that:
Support for referenced columns that are not primary key columns of the
referenced table is optional. Applications that use such mappings
will not be portable.
So whether or not this works will depend on your provider.
Warehouse:
#Data
#Entity
#JsonSnakeCase
public class WareHouse {
#Id
#GeneratedValue
private long id;
#Column(unique = true)
private String fcId;
#Enumerated(EnumType.STRING)
private FCStatus status;
#OneToMany(mappedBy = "warehouse", cascade = CascadeType.PERSIST, fetch = FetchType.EAGER)
private List<WorkingHours> workingHours;
#Enumerated(EnumType.STRING)
private IntegrationType integrationType;
}
WorkingHours:
#Data
#Entity
#JsonSnakeCase
public class WorkingHours {
#Id
#GeneratedValue
private long id;
#ManyToOne
#JoinColumn(name = "fcId", referencedColumnName="fcid")
private Warehouse warehouse;
private LocalDate date;
private DateTime start;
private DateTime end;
}
Related
I have three Entities i'm modeling and am having issues with the associated annotations. I basically have a class that I intend on returning to the caller, a nested listed of Project's and the Project can contain a nested list of Endpoint's. It's a top-level has-a one-to-many, then the nested one-to-many has two one-to-many's.
I've played with #JoinColumn annotations, i've attempted to put a #ManyToOne on the other side of the OneToMany's (but it doesn't like that it's a Long..). I'm just fairly new and unsure on how to do this. I think the mappedById is the solution, but i'm uncertain.
Main Issue: This code allows me to "save" to the database, but upon retrieval, the list of Project's inside the DownDetectorPackage is empty.
A CascadeType.ALL throws referential integrity errors that I don't completely understand.
#Data
#NoArgsConstructor
#AllArgsConstructor
#Entity
#Builder
public class DownDetectorPackage {
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
private long id;
#OneToMany(mappedBy="id",fetch = FetchType.EAGER)
private List<Project> projects;
#Temporal(TemporalType.DATE)
private Date dateJobsLastRan;
#Entity
#Data
#NoArgsConstructor
#AllArgsConstructor
#Builder
public class Project{
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
private long id;
private String projectName;
#OneToMany(mappedBy="id")
private List<Service> externalDependencies;
#OneToMany(mappedBy="id")
private List<Service> endpoints;
}
#Entity
#Data
#NoArgsConstructor
#AllArgsConstructor
#Builder
public class Service {
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
private Long id;
private String url;
private Boolean endpointIsUp;
private String serviceName;
}
You should be using #JoinColumn instead of mappedBy. MappedBy can be used when you have used #ManyToOne in the other class too, which you haven't.
So your final class should look something like this (this is applicable for the other classes too which you have mentioned) :
public class DownDetectorPackage {
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
private long id;
#JoinColumn(name = "downDetectorPackageId")
#OneToMany(fetch = FetchType.EAGER)
private List<Project> projects;
#Temporal(TemporalType.DATE)
private Date dateJobsLastRan;
Also, remember to state the parent object name in #JoinColumn annotation, since it would create a column for that foreign key.
You should mark every join column as JoinColumn denotating the referenced column from the other entity. Then, you are supposed to say which relation type are using this column.
public class Project {
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
private long id;
private String projectName;
#JoinColumn(referencedColumnName = "id")
#OneToMany(fetch = FetchType.LAZY)
private ExternalDependencyEntity externalDependencies;
#JoinColumn(referencedColumnName = "id")
#OneToMany(fetch = FetchType.LAZY)
private EndpointEntity endpoints;
}
Finally, note that in a relational database, every fk column can takes only 1 value (pk of referenced entity id), so, on your entity, you should mark the data type as the entity you are refering to and no as a collection.
I think this sould solve your problem.
I have a
company table
department table
employee table.
I am using hibernate to persist data in the database.
1. One to Many Relationship between Company and Department .
A company can have multiple departments and a department can have multiple employees.
I have done corresponding one to many mapping of entities as mentioned in below code. Request to update these entities comes from UI in the JSON format.
I have provided company Id, department Id, and employee Id in the request.
Now Suppose If for a particular company , there is one department in the database with dept_id 3 . . In the Json request, I get a request to update that particular company with one more department. So after updation, previous entry should remain as it is, i.e department with ID 3 ,should remain untouched and new entry should be added with some department Id, say 4,.
Now that company would have two departments one with Id 3 and other with id 4.
How could this be achieved??..Also department entries , which are not there in the request, should be deleted from the database... Same goes for the relation between employee and department,.request may ask to add new employee for a particular department,keeping the existing one.
Please help me with this, what configuration/approach has to be done in my code, to achieve this.
Here is the code for these three tables:
#Entity
#Table(name = "COMPANY")
#Getter
#Setter
public class Company implements Serializable {
private static final long serialVersionUID = 1L;
#Id
#GeneratedValue(strategy = GenerationType.AUTO)
#Column(name = "company_id")
private long companyId;
#Column(name = "company_region")
private String companayRegion;
#Column(name = "company_code")
private String companyCode;
#OneToMany(mappedBy = "company", cascade = CascadeType.ALL)
private List<department> departments;
public Company() {
}
}
#Entity
#Table(name = "Department")
#Getter
#Setter
public class Department implements Serializable {
private static final long serialVersionUID = 1L;
#Id
#GeneratedValue(strategy = GenerationType.AUTO)
#Column(name = "dept_id")
private long departmentID;
#Column(name = "dep_code")
private String departmentCode;
#ManyToOne(fetch = FetchType.LAZY)
#JoinColumn(name = "company_id")
private Company company;
#OneToMany(mappedBy = "department", cascade = CascadeType.ALL)
private List<Employee> employees;
}
#Entity
#Table(name = "Employee")
#Getter
#Setter
public class Employee implements Serializable {
private static final long serialVersionUID = 1L;
#Id
#GeneratedValue(strategy = GenerationType.AUTO)
#Column(name = "employee_id")
private long employeeId;
#Column(name = "emp_code")
private String empCode;
#Column(name = "emp_name")
private String empname;
#Column(name = "employee_city")
private String employeeCity;
#ManyToOne(fetch = FetchType.LAZY)
#JoinColumn(name = "dept_id")
private Department department;
}
the mappings seem correct, what you need is to use merge to obtain an Hibernate-managed entity and copy the fields from the detached instance (coming from the REST api):
Company c = (Company) session.merge(companyFromDto);
Merge should take care to create a new Company, or update an existing one (depending if it is already in the DB) as well as cascade the associations.
Make sure your JSON contains companyId / departmentID / employeeId
Load the company by companyId
INSERT all department entries where departmentID == 0, and fetch the generated ID (Hibernate will update the POJO, or return a new one with the ID set)
UPDATE all department entries where departmentID > 0, and remember the used departmentID
Iterate over company.getDepartments() and iterator.remove() entries with departmentID not contained in the collection built from (3) and (4)
By persisting the company Hibernate will detect which departments were removed, and delete those
Do basically the same for the department -> employee relationship
I have a table PATIENT which has some fields. There's also a CONTACT table that has a field called 'patientId' that needs to store PATIENT's ID (which is autogenerated), and a PATIENT_CONTACT table that only relates the two tables.
Now, here comes the tricky part. There are three other tables: CONTACT_ADDRESS, CONTACT_PHONE, CONTACT_EMAIL. A row in CONTACT will have the same ID as one (and only one) of CONTACT_ADDRESS, CONTACT_PHONE and CONTACT EMAIL. How do I get this all to work?
I have tried so many approaches, this is what I have right now:
#Entity
#Table(name = "patient", schema = "patient")
public class PatientEntity {
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
#Column(name = "id")
private Long id;
//... more fields
#OneToOne
private ContactEmailEntity contactEmailEntity;
#OneToOne
private ContactAddressEntity contactAddressEntity;
#OneToOne
private ContactPhoneEntity contactPhoneEntity;
}
The three CONTACT_* classes are similar and they look like this:
#Table(name = "contact_address", schema = "patient")
public class ContactAddressEntity {
#Id
#Column(name = "id")
private Long id;
// ... more fields
#OneToOne(cascade = {CascadeType.ALL})
#MapsId
private ContactEntity contact;
}
And my CONTACT class looks like this:
#Table(name = "contacto", schema = "paciente")
public class ContactEntity {
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
#Column(name = "id")
private Long id;
//... more fields
Can you see things that don't look right or could be done better? I get all sorts of errors with every approach. My latest one is:
ERROR: column patientent0_.contact_address_entity_contact_id does not exist
when trying to do a simple patient find. Please, any help is appreciated!
I have 2 tables, the first one is quite variable, the second one contains only constants:
USER.ID USER.NAME USER.USER_TYPE (FK on USER_TYPE.ID)
INT VARCHAR(64) INT(1)
----------------------------------
1 Alex 3
2 Jane 1
3 Carl 3
USER_TYPE.ID USER_TYPE.VALUE
INT(1) VARCHAR(64)
------------------------------
1 PENDING
2 REGISTERED
3 BANNED
4 ACTIVE
The foreign key USER.USER_TYPE is required and refering to a primary key USER_TYPE.ID in table USER_TYPE (one-to-one relation). Here is my mapping in Hibernate.
User.java
#Entity
#Table(name = "USER")
public class User {
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
#Column(name = "ID")
private int id;
#Column(name = "NAME")
private String name;
#OneToOne(cascade = CascadeType.ALL, fetch = FetchType.EAGER)
#JoinColumn(name = "USER_TYPE")
private UserType userType;
}
UserType.java
#Entity
#Table(name = "USER_TYPE")
public class UserType {
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
#Column(name = "ID")
private int id;
#Column(name = "VALUE")
private String value;
}
My goal is to keep the enumerated values in the database. How to map UserType's value instead of id to User and validate it? I want to pass the constant VALUE to the String instead of its ID.
private String userType;
The expected result of the first user would be:
User[id=1, name=Alex, userType=Banned]
User[id=2, name=Jane, userType=Pending]
User[id=3, name=Carl, userType=Banned]
My attempt was to use this annotation on definition of table twice with both colums switched
#SecondaryTable(name="USER_TYPE",
pkJoinColumns={#PrimaryKeyJoinColumn(name="ID", referencedColumnName="USER_TYPE")}
)
and get the VALUE with
#Column(table="USER_TYPE", name="VALUE")
private String UserType;
however it leads to the error
Unable to find column with logical name: USER_TYPE in org.hibernate.mapping.Table(USER) and its related supertables and secondary tables
First you need to change the relation from #OneToOne to #ManyToOne as UserType can be used by one or many User and User can have one and one UserType.
Secondly use referencedColumnName which references :
The name of the column referenced by this foreign key column.
So User entity will be:
#Entity
#Table(name = "USER")
public class User {
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
#Column(name = "ID")
private int id;
#Column(name = "NAME")
private String name;
#ManyToOne(cascade = CascadeType.ALL, fetch = FetchType.EAGER)
#JoinColumn(name = "USER_TYPE", referencedColumnName = "VALUE")
private UserType userType;
}
In UserType you should apply a unique constraint using #NaturalId to value field + do not provide its setter, to prevent duplicate values as It may lead to inconsistency:
#Entity
#Table(name = "USER_TYPE")
public class UserType {
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
#Column(name = "ID")
private int id;
#NaturalId
#Column(name = "VALUE")
private String value;
}
Hope it solves the issue!
Enumerations could be simpler:
enum UserType {
PENDING,
REGISTERED,
BANNED,
ACTIVE
}
#Entity
#Table(name = "USER")
public class User {
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
#Column(name = "ID")
private int id;
#Column(name = "NAME")
private String name;
#javax.persistence.Enumerated
private UserType userType;
}
If you really need separated table and #OneToOne relation, you can use #Formula from Hibernate:
#Formula("(select ut.value from user_type ut where ut.ID = USER_TYPE)")
private String userType;
For this really special requirement you could use SecondaryTable annotation.
That is, you don't need UserType entity, but declare attribute userType as String in User entity with column mapping to the secondary table "USER_TYPE".
First of all, I suggest you use ManyToOne relation. and Not CascadeType.ALL if you are not planning update or delete on USER_TYPE table.
If you do not need adding new UserTypes frequently use enum for it. It will just work as you want.
Second solution: As long as fetch = FetchType.EAGER you can add A transient field and return value of UserType in getter.
I'm new to JPA and I have a case where in my opinion JoinColumn behaves different and I want to know why.
UserEntites should join authorites.
Organziations should join OrganizationSettings.
I have two different approaches and both work.
Case 1
UserEntity :
#Entity
#Table(name = "users")
#Inheritance(strategy = InheritanceType.JOINED)
public class UserEntity {
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
private Long id;
#OneToMany(cascade = CascadeType.ALL, fetch = FetchType.EAGER)
#JoinColumn(name = "userId")
private List<UserAuthority> authorities;
}
UserAuthoritiesEntity
#Entity(name = "authorities")
#Table(name = "authorities")
public class UserAuthority {
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
private Long id;
private Long userId;
private String authority;
}
Here in my opinion the JoinColumn name references to UserAuthority.userId - and it works as expected.
Case 2
See my two other classes:
OrganizationEntity:
#Entity
#Table(name="organization")
public class OrganizationEntity {
#Id
#GeneratedValue(strategy= GenerationType.IDENTITY)
private Long id;
#NotNull
private String url;
#NotNull
private String name;
#OneToOne (cascade = CascadeType.ALL,fetch = FetchType.EAGER)
#JoinColumn(name="id",updatable = false)
private OrganizationSettingsEntity settings;
}
OrganizationSettings:
#Entity
#Table(name = "organization_settings")
public class OrganizationSettingsEntity {
#Id
private Long organizationId;
}
As you can see here -> Organization is Joining OrganizationSettings with the name id - which works. But in OrganizationSettings there is no id - just organizationId. This works - but makes me wonder.
Why does the second one also work? Shouldn't it be #JoinColumn(name="organizationId") ?
Spring is nothing to do with it. JPA is a standard API.
1-N case : you will create a FK column in the authorities table with name userId (linking back to the users table). You seem to also want to REUSE that same column for this userId field in the element ... this will cause you problems sooner or later since reusing columns without marking the userId field as insertable=false, updatable=false will mean that both may try to update it. Either get rid of the userId field in the element, or convert the field to be of type UserEntity (and have it as a bidirectional relation, using mappedBy on the 1-N owner field), or mark the userId field with those attributes mentioned earlier.
1-1 case : you will create a FK column in the organization table with name id (linking across to the organization_settings table). Sadly this is the same column as the PK of that table is going to use, so again you are reusing the column for 2 distinct purposes, and hell will result. Change the column of the relation FK to something distinct - the FK is in the organization table, not the other side.