I recently asked this question : Spring Mongodb - Insert Nested document?
And found out that Spring-Data-MongoDB does not support such behavior - so now I need a working alternative.
Now - to avoid having you look at the code on another page, I am going to paste it here from the other question... Here are my two POJOs :
#Document
public class PersonWrapper {
#Id
private ObjectId _Id;
#DBRef
private Person leader;
#DBRef
List<Person> delegates;
// Getters and setters removed for brevity.
}
public class Person
{
#Id
private ObjectId _Id;
private String name;
// Getters and setters removed for brevity.
}
Now, what I want to be able to do here - is send up a JSON object in my POST request as follows :
{
"personWrapper":
{
"_Id":"<ID HERE (MIGHT WANT SQL TO GENERATE THIS DURING CREATE>",
"leader":{
"_Id":"<ID HERE (MIGHT WANT SQL TO GENERATE THIS DURING CREATE>",
"name":"Leader McLeaderFace"
},
delegates:[{...},{...},{...}]
}
}
At this point - I would like the SQL side of this to create the individual records needed - and then insert the PersonWrapper record, with all of the right foreign keys to the desired records, in the most efficient way possible.
To be honest, if one of you thinks I am wrong about the Spring-Data-MongoDB approach to this, I would still be interested in the answer - because it would save me the hassle of migrating my database setup. So I will still tag the spring-data-mongodb community here, too.
If I understand well you want to cascade the save of your objects ?
ex : you save a PersonWrapper with some Person in the delegates property and spring data will save PersonneWrapper in a collection and save also the list of Person in another Collection.
It is possible to do that with Spring DATA JPA if you annotate your POJO with the JPA annotation #OneToMany and setup cascade property of this annotation. See this post
However the cascade feature is not available for Spring DATA mongoDB. See documentation .First you have to save the list of Person and then you save PersonWrapper.
Related
I have a model class that I store in Redis and I use Jpa Repository with Spring java. Normally(not with redis) jpa repository is saving the new data or updates(conditionally) if the given model is already exist in Db. Here, I want to add new item to redis but if it is not already exists on db otherwise update it just like usual Jpa implementation.
Here is my model:
#Getter
#Setter
#RedisHash("MyRecord")
public class MyRecordRedisModel {
private String id;
#Id
#Indexed
private String recordName;
private Date startDate;
private Date endDate;
}
And my repository class is just a normal spring jpa repo as follows:
#Repository
public interface IFRecordRedisRepository extends JpaRepository<IFRecordRedisModel, String> {
Page<IFRecordRedisModel> findAll(Pageable pageable);
}
Unique key must be the name (I totally do not care about uniquiness of the id). Thus, if the name is already exist in Db than do not add it again. I marked it as Indexed but still it is adding same data (with same recordName).
How can I make it unique?
This would require an additional query, but I think this solution would work for you. You can use query by Example to check if there exists a record with that name, and save conditionally, or do something else if it already exists.
IFRecordRedisModel exampleRecord = new IFRecordRedisModel();
exampleRecord.setRecordName(inputRecord.getRecordName());
if (!repository.exists(Example.of(exampleModel)))
repository.save(inputRecord);
else ..... // do something else
required format image
I want to object data into MongoDB using spring and I have hardcoded it.
please how to write a schema for that and I have taken it as an example only.
I have a different type of categories in it I have taken only clothes.
please tell me how to write one schema for a different type of categories and query too.
please find the attachment for your reference
I would recommend going though Spring Data MongoDB documentation for specifics on mapping java objects to MongoDB documents. Your case would look similar to:
#Document
public class Clothes {
#Id
private ObjectId id;
private Men men;
private Women women;
// getters & setters
}
You would need to define each sub class but this should be the gist of it.
What you can do is create a simple POJO (Plain Old Java Object) and with that you can insert that object into the data base. The the following example:
#Document
public class OAuthModel implements Serializable {
#Id
String username;
#Indexed
String oAuthID;
#Indexed
String type;
// Getter and Setters and Construct.
}
When I insert this object in the DB by calling:
OAuthModel authModel = new OAuthModel(username,firebaseToken.getUid(), OAuthHosts.GOOGLE.getType());
oAuthRepo.insert(authModel);
It will then be seen as this in the Database:
Keep in mind this will work no matter what your object looks like, you can have hashmaps etc. The should be a built in serialization.
I have an Account entity and I'm trying to persist it using save function. My code:
#Override
public Account createAccount(String pin) {
Account account = new Account();
account.setBalance(0L);
account.setPin(pin);
return accountRepository.save(account);
}
Now my entity class has an autogenerated field called accountNumber. My entity class:
#Entity
#Table(name = "accounts")
#Data
public class Account {
#Column(name = "account_number", length = 32, insertable = false)
private String accountNumber;
private Long balance;
}
Now after calling save, the entity returned has accountNumber as null but i can see in the intellij database view that it is actually not null. All the other auto-generated fields like id etc are there in the returned entity just the accountNumber is null. Default value for accountNumber is set in the sql file :
ALTER TABLE accounts
ALTER COLUMN account_number SET DEFAULT DefaultValueSerializer(TRUE, TRUE, 12);
Here, DefaultValueSerializer is the function which is generating the account number.
I've tried other solutions available here like using saveAndFlush() etc, nothing worked in my case. What can be an issue?
As mentioned in comment Hibernate is not aware about what happens in database engine level so it does not see the value generated.
It would be wise to move generation of account number to JPA level instead of using db defaults.
I suggest you to study annotations #GeneratedValue and related stuff like #SequenceGenerator. That way the control of generating account number is in JPA level and there is no need for stuff like refreshing entity after save.
One starting point: Java - JPA - Generators - #SequenceGenerator
For non-id fields it is possible to generate value in method annotated with #PrePersist as other answer suggests but you could do the initialization already in the Accounts constructor .
Also see this answer for options.
You can create an annotated #PrePersist method inside the entity in which you set its fields to their default value.
That way jpa is going to be aware of the default.
There are other such annotation avaiable for different entity lifecycle event https://docs.jboss.org/hibernate/entitymanager/3.6/reference/en/html/listeners.html
P.s. if you decide to go this way remember to remove the insertable = false
Use
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
for your IDs. And also leave your saving to saveAndFlush so you can immediately see the changes, If any. I'd also recommend separating IDs and account numbers. They should not be the same. Try debugging your program and see where the value stops passing around.
I got a problem with simple Spring Data issue. Let's assume we got two entities.
public class Request {
// all normal stuff
#ManyToOne
private Document doc;
}
public class Document {
private Long id;
private String name;
}
Simple relation. My question is - is it possible to retrieve Request entities using Spring Data Method-DSL and sorting by Document? So what I want to achieve is to create repository method like:
public List<Request> findAllOrderByDoc()
or similar:
public List<Request> findAllOrderByDocId()
Unfortunately when I try that I am given error message saying that there is no Doc field or it cannot be mapped to long. I assume it is possible to be done using QueryDSL and predicates but I am wondering if this pretty obvious and simple thing can be done by plain Spring Data?
Yes, sure.
you need to provide the direction:
public List<Request> findAllOrderByDocAsc()
public List<Request> findAllOrderByDocDesc()
Okay. I am getting a little confused here...
Lets say I have a class called User.
class User {
// all variables
// all getters and setters
}
Now, I use JSR 303 validation and put #NotNull, #Range, etc here for the variables.
I use this as Form / Command object. Meaning, when a form a submitted, the values are validated and BindingResult gives me errors.
Should this be used as in Entity Object for Hibernate as well? (If so, I need to add other Hibernate annotations like #Entity, #Id, #Column, etc on top of Validation annotations)
When we load the data from Database, do these validations kick in as well? (If yes, what if the data is already existing, and do not confirm to the validations?)
Where do we normally write business validations, like for example, country exists or not in the database, xyz value exists in a different table, etc?
Questions arise here as well:
- User form may not have all the fields that exist in the User class
- Database table User may have more fields or less fields than User class
- Form may have fields from different objects as well, say User and and Order.
How do we handle these?
Trying to wrap my mind around it
No you shouldn't mix entities objects and values objects. Entities objects are for DB mapping and values objects are used in the presentation layer.
To validate an object annoted, you need to use a Validator (commonly used with a DataBinder. Spring validation)
Is it DB constraints or backend validation?
For your last question, that's one of the reason to have 2 differentes objects for your presentation layer and your persistence layer. This way values objects can match what is displayed or input by the user (Form).
Entity object is an object of our plain old java class(POJO) Model/Business class, which needs to be persisted in a database using Hibernate, while Value Type object is an object of another class but it is stored as a part of Entity object within a database table.
#Embeddable
#Data
#AllArgsConstructor
public class Address{
private String country;
private String city;
private String street1;
private String street2;
private postalCode;
}
#Entity
#Data
#AllArgsConstructor
public class Person{
#Id
private Long id;
private String firstName;
private String lastName;
private ing age;
private Address address;
}
}
So after running this code in spring and hibernate project you will see Person table in database is created with it's attributes and Address class attributes.
For more information, I suggest reading this:
[https://www.decodejava.com/hibernate-value-type-object.htm][1]