Get Data from 2 tables in spring boot jpa - java

I have one table which has all the api audit information - Table name : api_audit
I have one table which has extra information about every api call - Table name : api_audit_info
Inside api_audit I have primary key as "transaction_id".
I want all the data from api_audit table and some data from api_audit_info table.
I have written a custom query like -
#Query(select c from ApiAudit c INNER JOIN ApiAudiInfo t ON c.transactionId = t.msgId)
But the issue is that the result type that I am getting this way contains only ApiAudit type data.
What shall I do to get data from both the tables. Please help.
Note: I am using JpaRepository as I need paginated data.
I am fairly new to Spring boot and JPA so not sure exactly which direction to look to.

Whenever I need to join data from more than 1 table, I am using Jdbi.
Here you have the official documentation:
Remember to include the required dependencies and configure a bean for Jdbi in your project.
Then I create a repository class, POJO and query with all of the information which I need. For example:
select c.transaction_id as transactionId, t.name as name from ApiAudit c INNER JOIN ApiAudiInfo t ON c.transactionId = t.msgId
Here you have some code samples from official documentation
After you map your data to POJO, you can use
public PageImpl(List<T> content, Pageable pageable, long total)
to return paginated data.
There is a big chance that there is a better solution, but this works for me every time.

Related

Store java object which contains another object on a single table with JPA

I'm doing an exercise with Springboot that basically consists of a simple application with a Rest Controller who has to store an object received from POST request to a mysql db using JPA/Hibernate.
My problem is the following one:
the table has this structure:
And I have this pojo which has to map the table as an object:
If you pay attention, the table has a column named "CARD_HOLDER_FULL_NAME", but in the app, the card holder must be a separate object:
so, how do I specify that the fullName attribuite in the CaldHolderInfo class represents that column in the table?
I'm very rusty with Springboot/JPA/hibernate so I don't know how to proceed
You need to make CaldHolderInfo an Embeddable.
See JPA #Embedded And #Embeddable
And please, no images of code on this site.

Spring Boot: keywords supported for JPA

I wanted to perform the Spring JPA repository where wanted to apply the and operation among 2 columns where one column cloud have multiple values in it.
SQL query for the same:
select * from table_name where col1='col1_val' and col2 IN
('col2_val_a','col2_val_b','col2_val_c');
I know that for and operation I can extend the JpaRepository and create the method with like this for:
List<MyPoJoObject> findByCol1AndCol2(String col1_val,String col2_val);
and for IN operation we can use : findByCol2In(Collection<String> col2_val)
But i did not know how i can club both the mentioned JPA default method into one, as per my sql statement mentioned before.
You can use the following method named:
List<MyPoJoObject> findByCol1AndCol2In(String col1_val, Collection<String> col2_val);
On this link repository-query-keywords you can find repository query keywords that you can use and combine them as well.
You can certainly combined both into one method.
List<MyPoJoObject> findByCol1AndCol2In(String col1_val,String[] col2_val);
Try this. I am not sure if it will accept Collection<String>. I will try that and update the answer.
HTH.
If you want to perform this logic for more than two columns then your method name becomes verbose.
Instead of stuck with Spring naming why can't you write your own JPA query.
Example:
#Query("select pojo from MyPoJoObject as pojo where pojo.col1 = :col1_val and pojo.col2 in :col2_val")
List<MyPoJoObject> findByColumns(String col1_val, List<String> col2_val);

How to obtain list of count() results using JpaRepository #Query?

I'm building REST API connected to ORACLE 11G DB. API sends data to Android client using JSON. To get data I'm using JpaRepository, and #Query annotations.
I want to provide data for charts: number of contracts in years.
I have native SQL query:
select aa.ROK, count(aa.NUMER_UMOWY)
from (select distinct NUMER_UMOWY, ROK from AGR_EFEKTY) aa
group by aa.ROK order by aa.ROK
Result of query using SQL Developer look like this:
I tried to get result using native query:
But result is always like this:
or error depending what I try.
Is it possible to obtain list of count() results using #Query?
If not, what should I use?
Thanks in advance :-)
I think What you are trying to use here is spring data projection.
As mentioned in the reference doc:
Spring Data query methods usually return one or multiple instances of
the aggregate root managed by the repository. However, it might
sometimes be desirable to create projections based on certain
attributes of those types. Spring Data allows modeling dedicated
return types, to more selectively retrieve partial views of the
managed aggregates.
and particularly closed projection where all accessor methods match the target attributes. In your case the count is not an attribute of your aggregate.
To perform what you want you can use constructor as follow :
class ContractsDto{
private String rok;
private int count;
public ContractsDto(String rok, int count) {
this.rok=rok;
this.count =count;
}
// getters
}
The query will be:
#Query(value = "select new ContractsDto(aa.rok , /*count */) from fromClause")
List<ContractsDto> getContractsPerYear();

OpenJPA inserting into one table data from another table

I am new to OpenJPA
I am trying to insert data into a table some of which comes from another table. Below is the scenario.
Table1: id, app_name, app_version, app_active
Table2: id, app_name, app_version, dev_name, dev_Lastname, dev_shortname,
Pojo1 maps fields to column of table1
Pojo2 maps fields to column of table2
Query:
insert into table2 ("dev_name","dev_lastname","dev_shortname") select t1.app_name, t1.app_version from Table1 t1 where t1.app_name = ?
i dont know how to run this query using Openjpa and how to map these fields to each other in two pojos.
if I use the Query object then what about the pojos?? will they come in use?? I mean will i need to do transaction.save??
Any help with a sample code appreciated.
Your query manipulates data directly in the database while JPA handles the object relationships.
Im not sure what problem you are trying to solve but can you read the Pojo1 convert it to a Pojo2 object that you just save?
Edit:
In you java application first retrieve your Pojo1 from the entity manager with some query.
Then Construct corresponding Pojo2 objects with the fields you want from Pojo1. Then just to entityManager.persist with your new Pojo2 objects.
This is quite complex to perform what you showed could be made in a one line sql statement.

JPA - Setting entity class property from calculated column?

I'm just getting to grips with JPA in a simple Java web app running on Glassfish 3 (Persistence provider is EclipseLink). So far, I'm really liking it (bugs in netbeans/glassfish interaction aside) but there's a thing that I want to be able to do that I'm not sure how to do.
I've got an entity class (Article) that's mapped to a database table (article). I'm trying to do a query on the database that returns a calculated column, but I can't figure out how to set up a property of the Article class so that the property gets filled by the column value when I call the query.
If I do a regular "select id,title,body from article" query, I get a list of Article objects fine, with the id, title and body properties filled. This works fine.
However, if I do the below:
Query q = em.createNativeQuery("select id,title,shorttitle,datestamp,body,true as published, ts_headline(body,q,'ShortWord=0') as headline, type from articles,to_tsquery('english',?) as q where idxfti ## q order by ts_rank(idxfti,q) desc",Article.class);
(this is a fulltext search using tsearch2 on Postgres - it's a db-specific function, so I'm using a NativeQuery)
You can see I'm fetching a calculated column, called headline. How do I add a headline property to my Article class so that it gets populated by this query?
So far, I've tried setting it to be #Transient, but that just ends up with it being null all the time.
There are probably no good ways to do it, only manually:
Object[] r = (Object[]) em.createNativeQuery(
"select id,title,shorttitle,datestamp,body,true as published, ts_headline(body,q,'ShortWord=0') as headline, type from articles,to_tsquery('english',?) as q where idxfti ## q order by ts_rank(idxfti,q) desc","ArticleWithHeadline")
.setParameter(...).getSingleResult();
Article a = (Article) r[0];
a.setHeadline((String) r[1]);
-
#Entity
#SqlResultSetMapping(
name = "ArticleWithHeadline",
entities = #EntityResult(entityClass = Article.class),
columns = #ColumnResult(name = "HEADLINE"))
public class Article {
#Transient
private String headline;
...
}
AFAIK, JPA doesn't offer standardized support for calculated attributes. With Hibernate, one would use a Formula but EclipseLink doesn't have a direct equivalent. James Sutherland made some suggestions in Re: Virtual columns (#Formula of Hibernate) though:
There is no direct equivalent (please
log an enhancement), but depending on
what you want to do, there are ways to
accomplish the same thing.
EclipseLink defines a
TransformationMapping which can map a
computed value from multiple field
values, or access the database.
You can override the SQL for any CRUD
operation for a class using its
descriptor's DescriptorQueryManager.
You could define a VIEW on your
database that performs the function
and map your Entity to the view
instead of the table.
You can also perform minor
translations using Converters or
property get/set methods.
Also have a look at the enhancement request that has a solution using a DescriptorEventListener in the comments.
All this is non standard JPA of course.

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