Using HibernateTemplate.find(...) with a String[] - java

I'm having troubles with HQL again :(
My desired SQL is this:
select employee.idemployee as id, employee.age as age,
employee.birthday as birthday, employee.firstName as firstName,
employee.gender as gender, employee.lastName as lastName from employee
employee
inner join employee_skillgroups skillgroup1 on
employee.idemployee=skillgroup1.idemployee
inner join employee_skillgroups skillgroup2 on
employee.idemployee=skillgroup.idemployee
where skillgroup1.idskillgroup = 'Sprachen'
and skillgroup.idskillgroup = 'SoftSkills'
But i just can't get HQL to generate me this ...
"Sprachen" and "SoftSkills" are two string coming out of a String[] I'm giving the method as a parameter. The method currently looks like this:
public List<Employee> findEmployeeWithTwoSkillGroups(final String[] skillGroups) {
return template.find("from Employee e join e.skillGroups as s where s in ?", Arrays.asList(skillGroups).toString
().substring(1, Arrays.asList(skillGroups).toString().length()-1));
}
I "cast" the array to a list, execute toString() on it (so i get "[Sprachen, SoftSkills]") and cut off the first and the last char (so i get "Sprachen, SoftSkills").
I guess the problem is that HQL generates "[...].idskillgroup in ('Sprachen, SoftSkills')", like it treats the two strings like ONE string ...
And i just can't get it to work like i want it to :/
Can someone please help me and give me a hint what to try/do next? :-)
Greetz
gilaras
Simmilar question:
HQL to get elements that possess all items in a set

The proper HQL statement should go more or less like this:
from Employee e join e.skillGroups as s where s in ( 'Foo', 'Bar', 'Baz' )
so you are missing the ' ' for each word.
EDIT: Now that I got what you want to achieve here :-)
I would recommend you doing this:
Query query = session.createQuery(
"from Employee e join e.skillGroups as s where s in (:skillGroups)");
// skillGroups must be a Collection type
query.setParameterList("skillGroups", skillGroups);
List list = query.list();
In case you need your result to be the AND of all elements of your String[] array, you can do the following:
Query query = session.createQuery(
"from Employee e join e.skillGroups as s where s in (:skillGroups) group by e having count(s) = :skillGroupsLength");
query.setParameterList("skillGroups", skillGroups);
query.setParameter("skillGroupsLength", skillGroups.length);
List list = query.list();

It's a prepared statement, not string concatenation. It handles ('Sprachen, SoftSkills') like a single string because it is a single string. You want to insert a collection in your query. I'm not sure how to do this in hibernateTemplate, but hibernate itself supports adding a collection. see the hibernate documentation.

Related

Returning List<Object> to variables;

I am doing a room database
#Query("SELECT distinct UserID FROM USER WHERE CovidStat=='T'")
public List<USER> checkCovid();
#Query("SELECT DISTINCT PID,VisitDate FROM USER_PLACE,USER WHERE User.UserID=USER_PLACE.UID AND UID=(:UID)")
int selectCovidPlace(int UID);
I wanted checkCovid() to return UserID where CovidStat='T' and I wanted to put the ID into selectCovidPlace to identify which place that ID been to. The problem is that checkCovid would return me a list instead of 1 variable since its not only 1 person who would have CovidStat='T', but im not sure that how can I put a list into selectCovidPlace().
I'm not familiar with SQLite. But the SQL syntax should be generic.
How about use IN statement?
like this ... WHERE User.UserID=USER_PLACE.UID AND UID IN (:UID)")
And then you can pass List as parameter.
Here you should use IN clause as below:
#Query("SELECT DISTINCT PID,VisitDate FROM USER_PLACE,USER WHERE User.UserID=USER_PLACE.UID AND UID IN (:UIDs)")
int selectCovidPlace(List<Integer> UIDs);

Mapping projection form hibernate HQL query into object

I am returning only a few columns from a table in DB:
List<MyClass> l = (List<MyClass>) session.createQuery("Select p.one, p.two FROM MyClass p WHERE p.id IN :id")
.setParameter("userId", id)
.list();
However, the query returns List of arrays, e.g
l.get(0) // [0] is object representing p.one in query, [1] p.two
Is there a hibernate some effective way how to map it to MyClass object? So the query would actually return list of MyClass objects where selected properties would have values, others would be set to null?
I have read about new MyClass(arg1,arg2) way in the query with construtor, however i have also read it is ineffective.
Thanks for help!
You can use try catch block and use query.getSingleResult() to return Object.
Query query = em.createNativeQuery("FROM TipoUsuario WHERE NAME = :name;", TipoUsuario.class)
.setParameter("name", name);
TipoUsuario tipoUsuario = null;
try
{
tipoUsuario = (TipoUsuario) query.getSingleResult();
}
catch ( Exception e )
{
return null;
}
createNativeQuery is just a sample. You can use createNamedQuery instead and put HQL in Entity with annotation #NamedQueries.
If you want to create MyClass you just need to use the fully-qualified name of the class in your query, e.g.
SELECT NEW my.pack.MyClass(p.one, p.two) FROM MyClass p WHERE p.id IN :id
I haven't heard of this being ineffective, and I can't image why it would be. It's just calling the constructor on the result instead of returning it as an array or object. Overall, it's probably a very good way of fetching, since you only select the fields that you need.
This and other options are also explained in more detail here.

createNativeQuery will not return rows in java but will in db2 sql [duplicate]

I know I can pass a list to named query in JPA, but how about NamedNativeQuery? I have tried many ways but still can't just pass the list to a NamedNativeQuery. Anyone know how to pass a list to the in clause in NamedNativeQuery? Thank you very much!
The NamedNativeQuery is as below:
#NamedNativeQuery(
name="User.findByUserIdList",
query="select u.user_id, u.dob, u.name, u.sex, u.address from user u "+
"where u.user_id in (?userIdList)"
)
and it is called like this:
List<Object[]> userList = em.createNamedQuery("User.findByUserIdList").setParameter("userIdList", list).getResultList();
However the result is not as I expected.
System.out.println(userList.size()); //output 1
Object[] user = userList.get(0);
System.out.println(user.length); //expected 5 but result is 3
System.out.println(user[0]); //output MDAVERSION which is not a user_id
System.out.println(user[1]); //output 5
System.out.println(user[2]); //output 7
The above accepted answer is not correct and led me off track for many days !!
JPA and Hibernate both accept collections in native query using Query.
You just need to do
String nativeQuery = "Select * from A where name in :names"; //use (:names) for older versions of hibernate
Query q = em.createNativeQuery(nativeQuery);
q.setParameter("names", l);
Also refer the answers here which suggest the same (I picked the above example from one of them)
Reference 1
Reference 2 which mentioned which cases paranthesis works which giving the list as a parameter
*note that these references are about jpql queries, nevertheless the usage of collections is working with native queries too.
A list is not a valid parameter for a native SQL query, as it cannot be bound in JDBC. You need to have a parameter for each argument in the list.
where u.user_id in (?id1, ?id2)
This is supported through JPQL, but not SQL, so you could use JPQL instead of a native query.
Some JPA providers may support this, so you may want to log a bug with your provider.
Depending on your database/provider/driver/etc., you can, in fact, pass a list in as a bound parameter to a JPA native query.
For example, with Postgres and EclipseLink, the following works (returning true), demonstrating multidimensional arrays and how to get an array of double precision. (Do SELECT pg_type.* FROM pg_catalog.pg_type for other types; probably the ones with _, but strip it off before using it.)
Array test = entityManager.unwrap(Connection.class).createArrayOf("float8", new Double[][] { { 1.0, 2.5 }, { 4.1, 5.0 } });
Object result = entityManager.createNativeQuery("SELECT ARRAY[[CAST(1.0 as double precision), 2.5],[4.1, 5.0]] = ?").setParameter(1, test).getSingleResult();
The cast is there so the literal array is of doubles rather than numeric.
More to the point of the question - I don't know how or if you can do named queries; I think it depends, maybe. But I think following would work for the Array stuff.
Array list = entityManager.unwrap(Connection.class).createArrayOf("int8", arrayOfUserIds);
List<Object[]> userList = entityManager.createNativeQuery("select u.* from user u "+
"where u.user_id = ANY(?)")
.setParameter(1, list)
.getResultList();
I don't have the same schema as OP, so I haven't checked this exactly, but I think it should work - again, at least on Postgres & EclipseLink.
Also, the key was found in: http://tonaconsulting.com/postgres-and-multi-dimensions-arrays-in-jdbc/
Using hibernate, JPA 2.1 and deltaspike data I could pass a list as parameter in query that contains IN clause. my query is below.
#Query(value = "SELECT DISTINCT r.* FROM EVENT AS r JOIN EVENT AS t on r.COR_UUID = t.COR_UUID where " +
"r.eventType='Creation' and t.eventType = 'Reception' and r.EVENT_UUID in ?1", isNative = true)
public List<EventT> findDeliveredCreatedEvents(List<String> eventIds);
can be as simple as:
#Query(nativeQuery =true,value = "SELECT * FROM Employee as e WHERE e.employeeName IN (:names)")
List<Employee> findByEmployeeName(#Param("names") List<String> names);
currently I use JPA 2.1 with Hibernate
I also use IN condition with native query. Example of my query
SELECT ... WHERE table_name.id IN (?1)
I noticed that it's impossible to pass String like "id_1, id_2, id_3" because of limitations described by James
But when you use jpa 2.1 + hibernate it's possible to pass List of string values. For my case next code is valid:
List<String> idList = new ArrayList<>();
idList.add("344710");
idList.add("574477");
idList.add("508290");
query.setParameter(1, idList);
In my case ( EclipseLink , PostGreSQL ) this works :
ServerSession serverSession = this.entityManager.unwrap(ServerSession.class);
Accessor accessor = serverSession.getAccessor();
accessor.reestablishConnection(serverSession);
BigDecimal result;
try {
Array jiraIssues = accessor.getConnection().createArrayOf("numeric", mandayWorkLogQueryModel.getJiraIssues().toArray());
Query nativeQuery = this.entityManager.createNativeQuery(projectMandayWorkLogQueryProvider.provide(mandayWorkLogQueryModel));
nativeQuery.setParameter(1,mandayWorkLogQueryModel.getPsymbol());
nativeQuery.setParameter(2,jiraIssues);
nativeQuery.setParameter(3,mandayWorkLogQueryModel.getFrom());
nativeQuery.setParameter(4,mandayWorkLogQueryModel.getTo());
result = (BigDecimal) nativeQuery.getSingleResult();
} catch (Exception e) {
throw new DataAccessException(e);
}
return result;
Also in query cannot use IN(?) because you will get error like :
Caused by: org.postgresql.util.PSQLException: ERROR: operator does not exist: numeric = numeric[]
'IN(?)' must be swapped to '= ANY(?)'
My solution was based on Erhannis concept.
In jpa, it worked for me
#Query(nativeQuery =true,value = "SELECT * FROM Employee as e WHERE e.employeeName IN (:names)")
List<Employee> findByEmployeeName(#Param("names") List<String> names);
Tried in JPA2 with Hibernate as provider and it seems hibernate does support taking in a list for "IN" and it works. (At least for named queries and I believe it will be similar with named NATIVE queries)
What hibernate does internally is generate dynamic parameters, inside the IN same as the number of elements in the passed in list.
So in you example above
List<Object[]> userList = em.createNamedQuery("User.findByUserIdList").setParameter("userIdList", list).getResultList();
If list has 2 elements the query will look like
select u.user_id, u.dob, u.name, u.sex, u.address from user u "+
"where u.user_id in (?, ?)
and if it has 3 elements it looks like
select u.user_id, u.dob, u.name, u.sex, u.address from user u "+
"where u.user_id in (?, ?, ?)
you should do this:
String userIds ="1,2,3,4,5";
List<String> userIdList= Stream.of(userIds.split(",")).collect(Collectors.toList());
Then, passes like parameter inside your query, like this:
#NamedNativeQuery(name="User.findByUserIdList", query="select u.user_id, u.dob, u.name, u.sex, u.address from user u where u.user_id in (?userIdList)")
It's not possible with standard JPA. Hibernate offers the proprietary method setParameterList(), but it only works with Hibernate sessions and is not available in JPA's EntityManager.
I came up with the following workaround for Hibernate, which is not ideal but almost standard JPA code and has some nice properties to it.
For starters you can keep the named native query nicely separated in a orm.xml file:
<named-native-query name="Item.FIND_BY_COLORS" result-class="com.example.Item">
<query>
SELECT i.*
FROM item i
WHERE i.color IN ('blue',':colors')
AND i.shape = :shape
</query>
</named-native-query>
The placeholder is wrapped in single quotes, so it's a valid native JPA query. It runs without setting a parameter list and would still return correct results when other matching color parameters are set around it.
Set the parameter list in your DAO or repository class:
#SuppressWarnings("unchecked")
public List<Item> findByColors(List<String> colors) {
String sql = getQueryString(Item.FIND_BY_COLORS, Item.class);
sql = setParameterList(sql, "colors", colors);
return entityManager
.createNativeQuery(sql, Item.class)
.setParameter("shape", 'BOX')
.getResultList();
}
No manual construction of query strings. You can set any other parameter as you normally would.
Helper methods:
String setParameterList(String sql, String name, Collection<String> values) {
return sql.replaceFirst(":" + name, String.join("','", values));
}
String getQueryString(String queryName, Class<?> resultClass) {
return entityManager
.createNamedQuery(queryName, resultClass)
.unwrap(org.hibernate.query.Query.class) // Provider specific
.getQueryString();
}
So basically we're reading a query string from orm.xml, manually set a parameter list and then create the native JPA query. Unfortunately, createNativeQuery().getResultList() returns an untyped query and untyped list even though we passed a result class to it. Hence the #SuppressWarnings("unchecked").
Downside: Unwrapping a query without executing it may be more complicated or impossible for JPA providers other than Hibernate. For example, the following might work for EclipseLink (untested, taken from Can I get the SQL string from a JPA query object?):
Session session = em.unwrap(JpaEntityManager.class).getActiveSession();
DatabaseQuery databaseQuery = query.unwrap(EJBQueryImpl.class).getDatabaseQuery();
databaseQuery.prepareCall(session, new DatabaseRecord());
Record r = databaseQuery.getTranslationRow();
String bound = databaseQuery.getTranslatedSQLString(session, r);
String sqlString = databaseQuery.getSQLString();
An alternative might be to store the query in a text file and add code to read it from there.
You can pass in a list as a parameter, but:
if you create a #NamedNativeQuery and use .createNamedQuery(), you don't use named param, you used ?1(positional parameter). It starts with 1, not 0.
if you use .createNativeQuery(String), you can use named param.
You can try this :userIdList instead of (?userIdList)
#NamedNativeQuery(
name="User.findByUserIdList",
query="select u.user_id, u.dob, u.name, u.sex, u.address from user u "+
"where u.user_id in :userIdList"
)

JPA lookups with arrays

I have an unidirectional relationship. Here i have Employee and Andress entities. In Employee entity i have the following code:
#OneToOne(cascade=CascadeType.ALL)
#JoinColumn(name = "HOME_ADDRESS")
private Address homeAddress;
I have an array of Adress objects and want to write a lookup that would return an array of Customer objects mapped to those adresses.
select e from Employee e where e.homeAddress.id IN '?'
I don't know what to do with the '?' part. Is the only option to loop over the address array, add id's to a string and pass it as a parameter to the query above, or is there a way to pass the array to the query and expect the same result?
No, you don't pass that as a String, but as a collection of IDs. And your query is invalid. It should be:
String jpql = "select e from Employee e where e.homeAddress.id IN :addresses";
Set<Long> addressIds = Arrays.stream(addresses)
.map(Address::getId)
.collect(Collectors.toSet());
return em.createQuery(jpql, Employee.class)
.setParameter("addresses", addressIds)
.getResultList();
This uses Java 8 to transform the array of addresses into a set of IDs, but you can of course use a goold old for loop.
2 Solutions:
HQL
String hql="select e from Employee e where e.homeAddress.id IN (:addresses)";
Query query = getSession().createQuery(hql);
query.setParameterList("addresses", your_list_address_collection);
Criteria
Criteria criteria = session.createCriteria(Employee.class);
criteria.add(Restrictions.in("addresses", your_list_address_collection));

Native Query Result Parameter is Not mapped to Class Modal

I have using the Native Query in JPA Repository and my query is as:
select u.*, max(a.version_no) as versionNo from users u left join andother_table a on u.id=a.user_id where u.title='abc' group by id;
from my Query i get the "versionNo" which is not mapped to mu user modal.I have put this also in our user modal like as
#Transient
private String versionNo;
with is getter/setter.but in view i will get versionNo is null.
Please help me.
It is null because you annotated it as #Transient, so it is not populated with DB values. You can execute the query without mapping the results directly to your class, and populate the class manually (the query will return a list of Object[]). Other than this, I'm not aware of any alternatives (because of #Transient).
List<Object[]> results = session.createNativeQuery("select max(a.version_no) as versionNo, u.* from users u left join andother_table a on u.id=a.user_id where u.title='abc' group by id").list();
List<MyClass> myClasses = new ArrayList<MyClass>();
for (Object[] result : results) {
MyClass mc = new MyClass();
...
mc.setVersionNo(result[0]);
mc.setSomethingElse(result[1])
...
myClasses.add(mc);
}
Each entry in results list is an object array representing a row returned by native query. Columns are ordered as you select them, so if you put versionNo in the first place in SELECT clause, it will be available with result[0].

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