Develop Reference

Using Spring JPA to setup a Aggregate Function for STRING_AGG with Postgresql for a Group_By

I am trying to setup a repository call to retrieve the ID's of a list of test results ids used in the GROUP_BY. I can get this to work using createNativeQuery but I am unable to get this to work using Spring's JPA with the FUNCTION call.
FUNCTION('string_agg', FUNCTION('to_char',r.id, '999999999999'), ',')) as ids
I am using Spring Boot 1.4, hibernate and PostgreSQL.
Question
If someone can please help me out to setup the proper function call
shown below in the JPA example it would be much appreciated.
Update 1
After implementing the custom dialect it looks like its trying to cast the function to a long. Is the Function code correct?
FUNCTION('string_agg', FUNCTION('to_char',r.id, '999999999999'), ','))
Update 2
After looking into the dialect further it looks like you need to register the return type for your function otherwise it will default to a long. See below for a solution.
Here is my code:
DTO
#Data
#NoArgsConstructor
#AllArgsConstructor
public class TestScriptErrorAnalysisDto {
private String testScriptName;
private String testScriptVersion;
private String checkpointName;
private String actionName;
private String errorMessage;
private Long count;
private String testResultIds;
}
Controller
#RequestMapping(method = RequestMethod.GET)
#ResponseBody
public ResponseEntity<Set<TestScriptErrorAnalysisDto>> getTestScriptErrorsByExecutionId(#RequestParam("executionId") Long executionId) throws Exception {
return new ResponseEntity<Set<TestScriptErrorAnalysisDto>>(testScriptErrorAnalysisRepository.findTestScriptErrorsByExecutionId(executionId), HttpStatus.OK);
}
Repository trying to use Function Not working
#Query(value = "SELECT new com.dto.TestScriptErrorAnalysisDto(r.testScriptName, r.testScriptVersion, c.name, ac.name, ac.errorMessage, count(*) as ec, FUNCTION('string_agg', FUNCTION('to_char',r.id, '999999999999'), ',')) "
+ "FROM Action ac, Checkpoint c, TestResult r " + "WHERE ac.status = 'Failed' " + "AND ac.checkpoint = c.id " + "AND r.id = c.testResult " + "AND r.testRunExecutionLogId = :executionId "
+ "GROUP by r.testScriptName, r.testScriptVersion, c.name, ac.name, ac.errorMessage " + "ORDER by ec desc")
Set<TestScriptErrorAnalysisDto> findTestScriptErrorsByExecutionId(#Param("executionId") Long executionId);
Repository using createNativeQuery working
List<Object[]> errorObjects = entityManager.createNativeQuery(
"SELECT r.test_script_name, r.test_script_version, c.name as checkpoint_name, ac.name as action_name, ac.error_message, count(*) as ec, string_agg(to_char(r.id, '999999999999'), ',') as test_result_ids "
+ "FROM action ac, checkpoint c, test_result r " + "WHERE ac.status = 'Failed' " + "AND ac.checkpoint_id = c.id "
+ "AND r.id = c.test_result_id " + "AND r.test_run_execution_log_id = ? "
+ "GROUP by r.test_script_name, r.test_script_version, c.name, ac.name, ac.error_message " + "ORDER by ec desc")
.setParameter(1, test_run_execution_log_id).getResultList();
for (Object[] obj : errorObjects) {
for (Object ind : obj) {
log.debug("Value: " + ind.toString());
log.debug("Value: " + ind.getClass());
}
}
Here was the documents I found on FUNCTION
4.6.17.3 Invocation of Predefined and User-defined Database Functions
The invocation of functions other than the built-in functions of the Java Persistence query language is supported by means of the function_invocation syntax. This includes the invocation of predefined database functions and user-defined database functions.
function_invocation::= FUNCTION(function_name {, function_arg}*)
function_arg ::=
literal |
state_valued_path_expression |
input_parameter |
scalar_expression
The function_name argument is a string that denotes the database function that is to be invoked. The arguments must be suitable for the database function that is to be invoked. The result of the function must be suitable for the invocation context.
The function may be a database-defined function or a user-defined function. The function may be a scalar function or an aggregate function.
Applications that use the function_invocation syntax will not be portable across databases.
Example:
SELECT c
FROM Customer c
WHERE FUNCTION(‘hasGoodCredit’, c.balance, c.creditLimit)

In the end the main piece which was missing was defining the functions by creating a new class to extend the PostgreSQL94Dialect. Since these functions were not defined for the dialect they were not processed in the call.
public class MCBPostgreSQL9Dialect extends PostgreSQL94Dialect {
public MCBPostgreSQL9Dialect() {
super();
registerFunction("string_agg", new StandardSQLFunction("string_agg", new org.hibernate.type.StringType()));
registerFunction("to_char", new StandardSQLFunction("to_char"));
registerFunction("trim", new StandardSQLFunction("trim"));
}
}
The other issue was that a type needed to be set for the return type of the function on registration. I was getting a long back because by default registerFunction returns a long even though string_agg would return a string in a sql query in postgres.
After updating that with new org.hibernate.type.StringType() it worked.
registerFunction("string_agg", new StandardSQLFunction("string_agg", new org.hibernate.type.StringType()));

JAVA EclipseLink optional query parameters

I have query which filters items by certain conditions:
#NamedQueries({
#NamedQuery(
name = ITEM.FIND_ALL_PARAMS_BY_COMPANY_COUNTRY_GROUP,
query = "SELECT i FROM Item i where "
+ "((i.idCompany=:companyId AND i.idEMGroup=:groupId) "
+ "OR (i.idCompany=:companyId AND i.idEMCountry =:countryId AND i.idEMGroup is null) "
+ "OR (i.idCompany is null AND i.idEMCountry = :countryId AND i.idEMGroup is null)) "
+ "order by i.idEMCountry desc, i.idCompany desc, i.idEMGroup desc")
})
In some cases parameters idEMGroup o companyId can be null which generates sql looking like this IdEmCompany = 200630758) AND (IdEMGroup = NULL) and it is incorrect sql syntax is it possible to dynamically if value is null for it as 'Column IS NULL' instead of 'Column = NULL' without adding a lot of if's, or it's just better to rewrite this query using Criteria API and just check if value is present and add predicates on certain conditions ?

Correct answer would be to use CriteriaQuery.
Though it is also possible to construct the query dynamically but manipulating #NamedQuery is not possible or might require stuff that makes it not worth to do.
Instead you could construct the query first as a String and create TypedQuery by manipulating the query string
String strQuery = "SELECT i FROM Item i"; // .. + the rest of stuff
if(null==companyId) {
// add something like "companyId IS :companyId"
// ":companyId" coulöd also be NULL"
// but to enable using tq.setParameter("companyId", companyId)
// without checking if there is param "companyId" so there always will
} else {
// add something like "companyId=:companyId"
}
TypedQuery<Item> tq = entityManager.createQuery(strQuery, Item.class);
tq.setParameter("companyId", companyId);
There will be some IFs but so will be in CriteriaQuery construction also.

sql to hql throwing exception

I'm using hibernate in my project and I'm trying to convert an existing sql query from DaoImplementation class to hql,
The sql query I have is
JdbcTemplate select = new JdbcTemplate(dataSource);
String sql = "SELECT * FROM (SELECT site_id,rtc,sigplan,cycle_time,health,phase_no,phase_time,active_groups,groupscolour,ip "+
"FROM status_data where rtc>='" + fromDate + "' and rtc<'" + toDate + "' and "+
"site_id=" + SiteId + " order by rtc desc limit "+recordLimit+" )as temp ORDER BY RTC ASC";
I wrote the hql version to get data from HealthLog table as
String hql = " select f from (select h from HealthLog h where rtc>='"+fromDate+"' and rtc <'"+toDate+"' "
+ "and siteId = "+siteId+" order by rtc desc limit "+limit+" ) as f order by rtc asc ";
return super.readListByHql(hql);
But the above hql throws the following exception
org.hibernate.hql.internal.ast.QuerySyntaxException: unexpected token: ( near line 1, column 16 [ select f from (select h from com.traff.hibernate.model.HealthLog as h where rtc>='1974-08-01 14:10:00.0' and rtc <'1974-09-01 23:46:20.6' and siteId = 20 order by rtc desc limit 50000 ) as f order by rtc asc ]
at org.hibernate.hql.internal.ast.QuerySyntaxException.convert(QuerySyntaxException.java:54)
at org.hibernate.hql.internal.ast.QuerySyntaxException.convert(QuerySyntaxException.java:47)
at org.hibernate.hql.internal.ast.ErrorCounter.throwQueryException(ErrorCounter.java:79)
at org.hibernate.hql.internal.ast.QueryTranslatorImpl.parse(QueryTranslatorImpl.java:276)
at org.hibernate.hql.internal.ast.QueryTranslatorImpl.doCompile(QueryTranslatorImpl.java:180)
at org.hibernate.hql.intern
I also tried the below code snippet but that giving me wrong results
Criteria criteria = createEntityCriteria();
criteria.add(Restrictions.ge("rtc", fromDate));
criteria.add(Restrictions.lt("rtc", toDate));
criteria.add(Restrictions.eq("siteId", siteId));
criteria.setMaxResults(limit);
criteria.addOrder(Order.asc("rtc"));
criteria2 = criteria;
criteria2.addOrder(Order.desc("rtc"));
return criteria2.list();
Which is the correct way to achieve the result?

First of all, as already mentioned in the comments, you cannot do a subquery within the FROM clause in HQL.
See: Hibernate Documentation
Secondly, the limit keyword is not supported by HQL.
Usually you would use query.setFirstResult(0) and query.setMaxResults(recordLimit) methods where query has the type of the Query Interface. But since you are using the limit in a subquery, there is no way.
See: How to set a limit to inner query in Hibernate?
Some options:
Use a native SQLQuery
Since you are only sorting in the outer Query. You could only execute the inner query and sort in Java.
Example for Option 2:
Session session = factory.openSession();
Query query = session
.createQuery("FROM HealthLog "
+ "WHERE rtc >= :rtcL and rtc < :rtcG and siteId = :siteId "
+ "ORDER BY rtc DESC");
query.setParameter("rtcL", fromDate);
query.setParameter("rtcG", toDate);
query.setParameter("siteId", siteId);
query.setFirstResult(0);
query.setMaxResults(recordLimit);
List<HealthLog> res = query.list();
session.close();
Collections.sort(res, new Comparator<HealthLog>() {
public int compare(HealthLog o1, HealthLog o2) {
return o1.getRtc().compareTo(o2.getRtc());
}
});
The query above returns HealthLogs with all attributes. If you want to only retrieve specific attributes, you can add a SELECT new HealthLog(siteId,rtc,sigplan,cycle_time,...) to your Query with a fitting constructor in HealthLog.
Please note that the code snippet might not be ready to use, since i do not know your model and attribute names.

Hibernate updation not working

I am using following method to update data in database.
String hql = "UPDATE EmployeeSalary set salary = :sl,"
+ "monthYr=:dt "
+ "WHERE id =:id and client.id=:cid";
for (EmployeeSalary e : eList) {
Query query = session.createQuery(hql);
query.setParameter("sl", e.getSalary());
query.setParameter("dt", e.getMonthYr());
query.setParameter("id", e.getId());
query.setParameter("cid", e.getClient().getId());
int result = query.executeUpdate();
System.out.println("result is " + result);
if (eAttList.size() % 20 == 0) {
session.flush();
session.clear();
}
}
Is there any problem with code.
On execution it is showing
result is 0
How to resolve above problem.

The documentation about update queries says:
No "Forms of join syntax", either implicit or explicit, can be specified in a bulk HQL query. Sub-queries can be used in the where-clause, where the subqueries themselves may contain joins.
Your query seems to violate this rule: client.id=:cid is an implicit join to the client entity.
Note that you're making your life difficult. You could simply get the entity by ID from the session (using Session.get()), and update it. Update queries are useful to update many rows at once.

Setting ORDER BY and LIMIT clause on JPA Query

I'm very, very new to Hibernate and JPA. I want to be able to apply ORDER BY and LIMIT clauses to a Hibernate(?) query, but am coming up empty. NOTE: I inherited this code.
Here is the current code:
public SomeCoolResponse getSomeCoolResponse(String myId) {
String queryString = "select aThing from AWholeBunchOfThings aThing " +
"join aThing.thisOtherThing oThing join oThing.StillAnotherThing saThing " +
"where saThing.subthing.id = :id";
Query q = getEntityManager().createQuery(queryString);
q.setParameter("id", myId);
List<MyThings> list = q.getResultList();
if(list.size() > 0) {
return list.get(0);
}
return null;
}
Instead of getting an entire list and then just returning the first result (which is the only one we need), I'd like to be able to apply a LIMIT 0,1 clause so that the query will be faster. Also, the query needs to be sorted descending on aThing.created which is a UNIX timestamp integer.
I've tried altering queryString like this:
String queryString = "select aThing from AWholeBunchOfThings aThing " +
"join aThing.thisOtherThing oThing join oThing.StillAnotherThing saThing " +
"where saThing.subthing.id = :id ORDER BY aThing.created LIMIT 0,1";
But Hibernate still returns the entire set.
I've looked at using the JPA CriteriaBuilder API, but it hurt my brain.
I'm a total n00b when it comes to this, and any help is greatly appreciated!

I think you need
q.setMaxResults(1);
See also the accepted answer here.
How do you do a limit query in HQL?
As to the "order by" clause you may include it in the queryString.

The JPQL equivalent to LIMIT start,max is:
setFirstResult and setMaxResults:
q.setFirstResult(start);
q.setMaxResults(limit);