JPA: querying FK - java

I'm using EclipseLink(JPA 2.0) under Netbeans 7.0 with JDK 7. Adding more, this is a JavaSE.
I have this tables, Employee and Record where in the relation is Employee(1) --- (*)Records.
Adding more about the structure of the Record: RecordID (PK), EmployeeID(FK), Status, etc.
I wanted to query out from the Record Table (not using the Employee->Rental Collection) what records has a relation with the employee..
I tried using the query, it always returns an exception
Exception Description: Error compiling the query [SELECT r FROM Record r WHERE
r.employeeid = :employeeid], unknown state or association field
[employeeid] of class [Record].

From the information given it's not completely clear, but I believe you need to reference the id inside the Employee object.
eg. the correct query is probably:
SELECT r FROM Record r WHERE r.employee.id = :employeeid
(notice the extra dot in employee.id)
If this doesn't work, please provide us with some actual code of your Java classes.

Related

jOOQ JSON query results in ORA-00979

I'm trying to execute this query to an Oracle 19c database:
Field<JSON> employee = DSL.field("employee", JSON.class);
Table<Record1<JSON>> employees = dsl
.select(jsonObject(jsonEntry("id", EMPLOYEE.ID), jsonEntry("name", EMPLOYEE.NAME), jsonEntry("phones",
jsonArrayAgg(
jsonObject(jsonEntry("number", PHONE.PHONENUMBER), jsonEntry("type", PHONE.TYPE)))
)).as(employee))
.from(EMPLOYEE)
.join(PHONE).on(PHONE.EMPLOYEE_ID.eq(EMPLOYEE.ID))
.groupBy(EMPLOYEE.ID)
.asTable();
String json = dsl
.select(jsonArrayAgg(employees.field(employee)))
.from(employees)
.fetchOneInto(String.class);
But I get
org.springframework.jdbc.BadSqlGrammarException: jOOQ; bad SQL grammar
[select json_arrayagg("alias_113372058".employee) from
(select json_object(key ? value "EMPLOYEE"."ID", key ? value "EMPLOYEE"."NAME", key ? value json_arrayagg(json_object(key ? value "PHONE"."PHONENUMBER", key ? value "PHONE"."TYPE"))) employee from "EMPLOYEE" join "PHONE" on "PHONE"."EMPLOYEE_ID" = "EMPLOYEE"."ID" group by "EMPLOYEE"."ID") "alias_113372058"];
nested exception is java.sql.SQLSyntaxErrorException: ORA-00979: Kein GROUP BY-Ausdruck
Does jOOQs JSON feature not work with Oracle?
This isn't related to your JSON usage. The same thing would have happened if you removed all of it and wrote this query instead:
dsl.select(EMPLOYEE.ID, EMPLOYEE.NAME)
.from(EMPLOYEE)
.join(PHONE).on(PHONE.EMPLOYEE_ID.eq(EMPLOYEE.ID))
.groupBy(EMPLOYEE.ID);
Your query would work in MySQL, PostgreSQL or standard SQL, where you can still project all functionally dependent columns after grouping by a primary key column. But in Oracle, this doesn't work. So, you have to add EMPLOYEE.NAME to your GROUP BY clause.
There's a feature request to transform your SQL accordingly, but jOOQ 3.14 does not support this yet: https://github.com/jOOQ/jOOQ/issues/4725
Note that JSON_ARRAYAGG() aggregates empty sets into NULL, not into an empty []. If that's a problem, use COALESCE()

Spring Data JPA Specifications - Distinct + order by column in join

I have some specifications that I am combining with "and":
Specification.where(predicate1).and(predicate2).and(predicate3);
One of them has distinct set :
query.distinct(true);
Another one makes an order by on a column that is in a join.
query.orderBy(builder.desc(bJoin.get("orderbyColumn")));
This fails with a SQLGrammarException stating that order by column should be in distinct.
So basically we have entity A, the main entity, and some nested entity B, we select from A but want to order by B, and in generated sql it only selects columns from A. The only way I found to make it work (= making it select from B as well) is to replace the join by a fetch :
Fetch < A, B > bFetch = root.fetch("joinCol", JoinType.INNER);
Join < A, B > bJoin = (Join < A, B > ) bFetch;
that worked for some time, was testing locally in H2, but then after some time started getting another error :
org.hibernate.QueryException: query specified join fetching, but the
owner of the fetched association was not present in the select list
I solved it somehow in my local pointing to H2 by requiring some columns to not be null, but in real server using PostgreSQL, it's not working at all, getting that error for all cases when a fetch is present.
My question is : what is the right way to use distinct along with orderby on a nested entity that is not fetched? Is my solution with fetch ok and it just needs to be fixed (and if so how?) or I should go for another option entirely?
For the actual query I am using this method :
findAll(Specification<>, Pageable)
Isn't there a way to have distinct wrapping the whole query with order by (some sort of subquery?) and bypassing all this nightmare? Have it generate a query like this:
select distinct colA1, colA2, coAl3 from (select colA1, colA2, coAl3
from A inner join B b on ........ order by b.colB1)
Do I need to convert my specification to predicate manually and do something else with it to try to solve my issues (some kind of hybrid approach)?
Any pieces of advice will be greatly appreciated.
I encountered same error but actually it was not error :)
findAll(Specification<>, Pageable) this method throws 2 different queries.
First one is count query where you have to be careful.
Second is the rows query where you actually did it.
You can check the query type with code below
if (query.getResultType() != Long.class && query.getResultType() != long.class){
root.fetch("entity1");
}

Spring Batch Paging with sortKeys and parameter values

I have a Spring Batch project running in Spring Boot that is working perfectly fine. For my reader I'm using JdbcPagingItemReader with a MySqlPagingQueryProvider.
#Bean
public ItemReader<Person> reader(DataSource dataSource) {
MySqlPagingQueryProvider provider = new MySqlPagingQueryProvider()
provider.setSelectClause(ScoringConstants.SCORING_SELECT_STATEMENT)
provider.setFromClause(ScoringConstants.SCORING_FROM_CLAUSE)
provider.setSortKeys("p.id": Order.ASCENDING)
JdbcPagingItemReader<Person> reader = new JdbcPagingItemReader<Person>()
reader.setRowMapper(new PersonRowMapper())
reader.setDataSource(dataSource)
reader.setQueryProvider(provider)
//Setting these caused the exception
reader.setParameterValues(
startDate: new Date() - 31,
endDate: new Date()
)
reader.afterPropertiesSet()
return reader
}
However, when I modified my query with some named parameters to replace previously hard coded date values and set these parameter values on the reader as shown above, I get the following exception on the second page read (the first page works fine because the _id parameter hasn't been made use of by the paging query provider):
org.springframework.dao.InvalidDataAccessApiUsageException: No value supplied for the SQL parameter '_id': No value registered for key '_id'
at org.springframework.jdbc.core.namedparam.NamedParameterUtils.buildValueArray(NamedParameterUtils.java:336)
at org.springframework.jdbc.core.namedparam.NamedParameterJdbcTemplate.getPreparedStatementCreator(NamedParameterJdbcTemplate.java:374)
at org.springframework.jdbc.core.namedparam.NamedParameterJdbcTemplate.query(NamedParameterJdbcTemplate.java:192)
at org.springframework.jdbc.core.namedparam.NamedParameterJdbcTemplate.query(NamedParameterJdbcTemplate.java:199)
at org.springframework.batch.item.database.JdbcPagingItemReader.doReadPage(JdbcPagingItemReader.java:218)
at org.springframework.batch.item.database.AbstractPagingItemReader.doRead(AbstractPagingItemReader.java:108)
Here is an example of the SQL, which has no WHERE clause by default. One does get created automatically when the second page is read:
select *, (select id from family f where date_created between :startDate and :endDate and f.creator_id = p.id) from person p
On the second page, the sql is modified to the following, however it seems that the named parameter for _id didn't get supplied:
select *, (select id from family f where date_created between :startDate and :endDate and f.creator_id = p.id) from person p WHERE id > :_id
I'm wondering if I simply can't use the MySqlPagingQueryProvider sort keys together with additional named parameters set in JdbcPagingItemReader. If not, what is the best alternative to solving this problem? I need to be able to supply parameters to the query and also page it (vs. using the cursor). Thank you!
I solved this problem with some intense debugging. It turns out that MySqlPagingQueryProvider utilizes a method getSortKeysWithoutAliases() when it builds up the SQL query to run for the first page and for subsequent pages. It therefore appends and (p.id > :_id) instead of and (p.id > :_p.id). Later on, when the second page sort values are created and stored in JdbcPagingItemReader's startAfterValues field it will use the original "p.id" String specified and eventually put into the named parameter map the pair ("_p.id",10). However, when the reader tries to fill in _id in the query, it doesn't exist because the reader used the non-alias removed key.
Long story short, I had to remove the alias reference when defining my sort keys.
provider.setSortKeys("p.id": Order.ASCENDING)
had to change to in order for everything to work nicely together
provider.setSortKeys("id": Order.ASCENDING)
I had the same issue and got another possible solution.
My table T has a primary key field INTERNAL_ID.
The query in JdbcPagingItemReader was like this:
SELECT INTERNAL_ID, ... FROM T WHERE ... ORDER BY INTERNAL_ID ASC
So, the key is: in some conditions, the query didn't return results, and then, raised the error above No value supplied for...
The solution is:
Check in a Spring Batch decider element if there are rows.
If it is, continue with chunk: reader-processor-writer.
It it's not, go to another step.
Please, note that they are two different scenarios:
At the beginning, there are rows. You get them by paging and finally, there are no more rows. This has no problem and decider trick is not required.
At the beginning, there are no rows. Then, this error raised, and the decider solved it.
Hope this helps.

Hibernate returns list of nulls although executed SQL returns values

I'm using hibernate as an ORMapper. I want to execute an actually rather simple hql query:
SELECT a
FROM Foo a
WHERE a.status = :A0status
ORDER BY a.bookingTypeCode ASC,
a.priority ASC
This hql query is then converted into a sql query which looks something like this:
select a.*
from Foo a
where a.status='A'
order by a.bookingtypecode ASC,
a.priority ASC
When I execute the sql on the oracle database using the Oracle SQL Developer I get 17 rows returned. However, when I execute the hql query (using the list method of a Query I get a list of 17 elements that are all null. Although the number of elements is correct, not a single one of the elements is actually loaded.
This is the way I create and execute my query:
// the hql query is stored in the hqlQuery variable;
// the parameter are stored in a Map<String, Object> called params
Query hQuery = hibSession.createQuery(hqlQuery);
for (Entry<String, Object> param : params.entrySet()) {
String key = param.getKey();
Object value = param.getValue();
hQuery.setParameter(key, value);
}
List<?> result = hQuery.list();
Does anyone know what might be the problem here?
Update 1
I've recently upgrade from hibernate 3.2 to 4.3.5. Before the upgrade everything worked fine. After the upgrade I get this error.
I've set the Log level of hibernate to TRACE and found the problem. It was actually a mapping/logic/database error. The primary key consisted of two columns (according to the entity class) and one of these columns was nullable. However a primary key can never be nullable. Therefore hibernate always returned null.
If you have not set a custom (and buggy) ResultTransformer, my second best guess is that your debugger is lying to you. Does you code actually receives a list of null?
Also make sure to test with the code you are showing is. Too many times, people simplify things and the devil is in the details.
This error is happening to me. MySQL query browser works, but in hibernate of 7 columns and only one column always came with all null fields. I checked all the ids and they were not null. The error was in the construction of SQL Native. I had to change the way of writing it. Ai worked.
SELECT c.idContratoEmprestimo as idContratoEmprestimo,
c.dtOperacao as dataOperacao,
p.cpf as cpf,
p.nome as nome,
(Select count(p2.idParcelaEmprestimo) from EMP_PARCELA p2 where p2.valorPago > 0 and p2.dtPagamento is not null
and p2.idContratoEmprestimo = c.idContratoEmprestimo and p2.mesCompetencia <= '2014-08-01') as parcelasPagas, c.numeroParcelas as numeroParcelas,
pe.valorPago as valorParcela
FROM EMP_CONTRATO c inner join TB_PARTICIPANTE_DADOS_PLANO AS pp on pp.idParticipantePlano = c.idParticipantePlano
inner join TB_PARTICIPANTE as p on p.id = pp.idParticipante
inner join TB_PARTICIPANTE_INSTITUIDOR as pi on pi.PARTICIPANTE_ID = p.id
inner join EMP_PARCELA as pe on pe.idContratoEmprestimo = c.idContratoEmprestimo
where c.dtInicioContrato <= '2014-08-01' and pi.INSTITUIDOR_ID = 1
and c.avaliado is true
and pe.mesCompetencia = '2014-08-01'
and c.deferido is true
and c.dtQuitacao is null
and c.dtExclusao is null
and pe.valorPago is not null
group by c.idContratoEmprestimo
order by p.nome

"No row with the given identifier exists" although it DOES exist

I am using Hibernate and getting
Exception in thread "main" org.hibernate.ObjectNotFoundException: No row with the given identifier exists: [#271]
What is pretty weird about this error is, that the object with the given id exists in the database. I inserted the problematic record in another run of the application. If I access it in the same run (i.e. same hibernate session) there seem to be no problems retrieving the data.
Just because it could be a fault of the mapping:
public class ProblemClass implements Persistent {
#ManyToOne(optional = false)
private MyDbObject myDbObject;
}
public class MyDbObject implements Persistent {
#OneToMany(mappedBy = "myDbObject")
private List<ProblemClass> problemClasses;
#ManyToOne(optional = false)
private ThirdClass thirdClass;
}
I have absolutely no clue even where to look at. Any hints highly appreciated!
Just to clarify:
The data was inserted in another RUN of the application. It is definitely in the database, as I can see it via an SQL-Query after the application terminated. And after THAT, i.e. when starting the application again, I get the error in the FIRST query of the database -- no deletion, no rollback involved.
Addition:
Because it was asked, here is the code to fetch the data:
public List<ProblemClass> getProblemClasses() {
Query query = session.createQuery("from ProblemClass");
return query.list();
}
And just to make it complete, here is the generic code to insert it (before fetching in another RUN of the application):
public void save(Persistent persistent) {
session.saveOrUpdate(persistent);
}
Eureka, I found it!
The problem was the following:
The data in the table ThirdClass was not persisted correctly. Since this data was referenced from MyDbObject via
optional = false
Hibernate made an inner join, thus returning an empty result for the join. Because the data was there if executed in one session (in the cache I guess), that made no problems.
MySQL does not enforce foreign key integrity, thus not complaining upon insertion of corrupt data.
Solution: optional = true or correct insertion of the data.
Possible reasons:
The row was inserted by the first session, but transaction was not committed when second session tried to access it.
First session is roll-backed due to some reason.
Sounds like your transaction inserting is rollbacked
Main reason behind this issue is data mismatch, for example i have entity mapping class called "X" and it has column "column1" and it has reference to the table "Y" column "column1" as below
#OneToOne(cascade = CascadeType.ALL)
#JoinColumn(name = "column1", referencedColumnName = "column1")
public Y getColumn1() {
return Y;
}
In this if X table column1 has value but Y table column1 is not having the value. Here link will be failed.
This is the reason we will get Hibernate objectNotFound exception
This issue can also be resolved by creating proper data model like creating proper indexing and constraints (primary key/foreign key) ..
This might be your case, kindly check my answer on another post.
https://stackoverflow.com/a/40513787/6234057
I had the same Hibernate exception.
After debugging for sometime, i realized that the issue is caused by the Orphan child records.
As many are complaining, when they search the record it exists.
What i realized is that the issue is not because of the existence of the record but hibernate not finding it in the table, rather it is due to the Orphan child records.
The records which have reference to the non-existing parents!
What i did is, find the Foreign Key references corresponding to the Table linked to the Bean.
To find foreign key references in SQL developer
1.Save the below XML code into a file (fk_reference.xml)
<items>
<item type="editor" node="TableNode" vertical="true">
<title><![CDATA[FK References]]></title>
<query>
<sql>
<![CDATA[select a.owner,
a.table_name,
a.constraint_name,
a.status
from all_constraints a
where a.constraint_type = 'R'
and exists(
select 1
from all_constraints
where constraint_name=a.r_constraint_name
and constraint_type in ('P', 'U')
and table_name = :OBJECT_NAME
and owner = :OBJECT_OWNER)
order by table_name, constraint_name]]>
</sql>
</query>
</item>
2.Add the USER DEFINED extension to SQL Developer
Tools > Preferences
Database > User Defined Extensions
Click "Add Row" button
In Type choose "EDITOR", Location - where you saved the xml file above
Click "Ok" then restart SQL Developer
3.Navigate to any table and you will be able to see an additional tab next to SQL, labelled FK References, displaying FK information.
4.Reference
http://www.oracle.com/technetwork/issue-archive/2007/07-jul/o47sql-086233.html
How can I find which tables reference a given table in Oracle SQL Developer?
To find the Orphan records in all referred tables
select * from CHILD_TABLE
where FOREIGNKEY not in (select PRIMARYKEY from PARENT_TABLE);
Delete these Orphan records, Commit the changes and restart the server if required.
This solved my exception. You may try the same.
Please update your hibernate configuration file as given below:
property start tag name="hbm2ddl.auto" create/update property close tag
I have found that in Oracle this problem can also be caused by a permissions issue. The ProblemClass instance referred to by the MyDbObject instance may exist but have permissions that do not allow the current user to see it, even though the user can see the current MyDbObject.

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