I am working in Hibernate with Spring and used Spring Hibernate template (getHibernateTemplate().find(String query,Object values)) for replacing positioned parameter with values.
My query is:
from className classObject where classObject.variableOne = ? and classObject.variableTwo = ?
and my parameter is an ArrayList<String> with 2 values.
The getHibernateTemplate().find(String query,Object values) assigned the ArrayList values automatically in the where clause (As you can see, I didn't bind parameters manually) and returned me the result.
Now, I removed spring from my application and using only hibernate. So I would like to know,
Is there any equivalent method available in hibernate (Session or
Query) classes which gives same functionality as above where I will pass HQL and values?
Thanks in Advance.
You have to use something like below
private void setParamValues(final String[] paramValues, SQLQuery query) {
if (paramValues != null && paramValues.length > 0) {
for (int liCnt = 0; liCnt < paramValues.length; liCnt++) {
query.setString(liCnt, paramValues[liCnt]);
}
}
}
SQLQuery will replace the ? with passed parameter's value. Keep in mind sequence in the paramValues array should be the same as wrote in the query.
Above has been worked in my case, am sure this will work in your case as well.
This is not Hibernate method, your have to use this method before calling the database.
Related
I am trying to migrate to neo4j 6. Whats the equivalent of this method in neo4j6?
The Result here contains: {ref=Employee.... etc, so the actual Java objects.
//org.neo4j.ogm.session.Session is autowired
#GetMapping("/companies/{companyId}/refs")
public Result getCompanyRefs(#PathVariable final String companyId)
{
String query = "MATCH (company:Company)-[ref]-(refObj) where company.id=\"" + companyId + "\" RETURN company,ref,refObj";
return this.session.query(query, Collections.emptyMap());
}
I tried with the new neo4j driver like so:
//org.neo4j.driver.Driver is autowired
#GetMapping("/persons/{personId}/refs")
public Result getPersonRefs(#PathVariable final String personId)
{
String query = "MATCH (person:Person)-[ref]-(refObj) where person.id=\"" + personId + "\" RETURN person,ref,refObj";
return this.driver.session().run(query, Collections.emptyMap());
}
but this gives a Result which is not convertable to my #Node (entity) classes. The previous version gave a Result which contained the actual java objects(mapped to classes).
the result here is:Record<{person: node<7>, ref: relationship<8>, refObj: node<0>}>
Basically the main thing is: i need the nodes mapped to java objects. But i need them via a cypher query, because i need to do some things on the (Result) Nodes before deleting the relationships between them.
so it turns out it does give back the things i need.
Result result = this.getPersonRefs(id);
result.list().forEach((entry) -> {
The problem was that for example neither entry.get("refObj").asObject(), nor asNode() actually gave back what i thought it was supposed to give back.
The Solution:
entry.get("refObj").asMap()
this gives back the actual properties of the object. Then you just need to convert it to MyClass.class with an ObjectMapper.
I have a collection (A) which has two fields (String, integer) in mongoDB. I want to update the collection by adding some value to sting
Ex. Lets say i have a document A[field1 : ABC,field2 : 25]. I want to update it by adding ,say 5, to it so it will look like A[field1 :ABC,field2 : 30] after updation.
The code I have used for this is as follows:
Query query = new Query();
query.addCriteria(Criteria.where("field1").is("ABC));
BeanName beanName = template.findOne(query, BeanName.class,collectionName);
if(null != beanName){
Update update = new Update();
update.set("field1", "ABC");
update.set("field2", beanName.getField2() + 5)
template.updateFirst(query, update, BeanName.class,collectionName);
}
else{
template.save(beanName, collectionName); // the value of filed1 and field 2 is populated in a bean with instance 'beanName'
}
The code is woriking fine with expected results but the performance is very slow. Is there any other efficient way for it.
I am working on large amount of data to update.
I would suggest you to use findAndModify() method, in combination with the upsert = true feature. Please find the official documentation below :
https://docs.mongodb.org/manual/reference/method/db.collection.findAndModify/
Is it possible to fetch data in user defined ranges [int starting record -int last record]?
In my case user will define in query String in which range he wants to fetch data.
I have tried something like this
Pageable pageable = new PageRequest(0, 10);
Page<Project> list = projectRepository.findAll(spec, pageable);
Where spec is my defined specification but unfortunately this do not help.
May be I am doing something wrong here.
I have seen other spring jpa provided methods but nothing are of much help.
user can enter something like this localhost:8080/Section/employee? range{"columnName":name,"from":6,"to":20}
So this says to fetch employee data and it will fetch the first 15 records (sorted by columnName ) does not matter as of now.
If you can suggest me something better that would be great.if you think I have not provided enough information please let me know, I will provide required information.
Update :I do not want to use native or Create query statements (until I don't have any other option).
May be something like this:
Pageable pageable = new PageRequest(0, 10);
Page<Project> list = projectRepository.findAll(spec, new pageable(int startIndex,int endIndex){
// here my logic.
});
If you have better options, you can suggest me that as well.
Thanks.
Your approach didn't work, because new PageRequest(0, 10); doens't do what you think. As stated in docs, the input arguments are page and size, not limit and offset.
As far as I know (and somebody correct me if I'm wrong), there is no "out of the box" support for what you need in default SrpingData repositories. But you can create custom implementation of Pagable, that will take limit/offset parameters. Here is basic example - Spring data Pageable and LIMIT/OFFSET
We can do this with Pagination and by setting the database table column name, value & row counts as below:
#Transactional(readOnly=true)
public List<String> queryEmployeeDetails(String columnName,String columnData, int startRecord, int endRecord) {
Query query = sessionFactory.getCurrentSession().createQuery(" from Employee emp where emp.col= :"+columnName);
query.setParameter(columnName, columnData);
query.setFirstResult(startRecord);
query.setMaxResults(endRecord);
List<String> list = (List<String>)query.list();
return list;
}
If I am understanding your problem correctly, you want your repository to allow user to
Provide criteria for query (through Specification)
Provide column to sort
Provide the range of result to retrieve.
If my understanding is correctly, then:
In order to achieve 1., you can make use of JpaSpecificationExecutor from Spring Data JPA, which allow you to pass in Specificiation for query.
Both 2 and 3 is achievable in JpaSpecificationExecutor by use of Pagable. Pageable allow you to provide the starting index, number of record, and sorting columns for your query. You will need to implement your range-based Pageable. PageRequest is a good reference on what you can implement (or you can extend it I believe).
So i got this working as one of the answer suggested ,i implemented my own Pageable and overrided getPagesize(),getOffset(),getSort() thats it.(In my case i did not need more)
public Range(int startIndex, int endIndex, String sortBy) {
this.startIndex = startIndex;
this.endIndex = endIndex;
this.sortBy = sortBy;
}
#Override
public int getPageSize() {
if (endIndex == 0)
return 0;
return endIndex - startIndex;
}
#Override
public int getOffset() {
// TODO Auto-generated method stub
return startIndex;
}
#Override
public Sort getSort() {
// TODO Auto-generated method stub
if (sortBy != null && !sortBy.equalsIgnoreCase(""))
return new Sort(Direction.ASC, sortBy);
else
return new Sort(Direction.ASC, "id");
}
where startIndex ,endIndex are starting and last index of record.
to access it :
repository.findAll(spec,new Range(0,20,"id");
There is no offset parameter you can simply pass. However there is a very simple solution for this:
int pageNumber = Math.floor(offset / limit) + ( offset % limit );
PageRequest pReq = PageRequest.of(pageNumber, limit);
The client just have to keep track on the offset instead of page number. By this I mean your controller would receive the offset instead of the page number.
Hope this helps!
I want to set a parameter in a named query (JPA 2.0), so my dataTable would render the respective dataSet. The parameter is obtained remotely and injected in a AbstractFacade class.
I've tried to achieve this through the code above, but it's not working.
Can someone help me?
AbstractFacade (main code):
private String prefDep;
public List<T> findByPrefDep() {
prefDep= FacesContext.getCurrentInstance().getExternalContext().getSessionMap().get("xPrefDep");
javax.persistence.criteria.CriteriaQuery cq = getEntityManager().getCriteriaBuilder().createQuery();
cq.select(cq.from(entityClass));
return getEntityManager().createQuery(cq).setParameter("prefDep", prefDep).getResultList();
}
The Entity class (main code):
#NamedQuery(name = "Capacitacao.findByPrefDep", query = "SELECT c FROM Capacitacao c WHERE c.prefDep = :prefDep"),
The AbstractController:
public Collection<T> getItems() {
if (items == null) {
items = this.ejbFacade.findByPrefDep();
}
return items;
}
There is no exception launched, but the dataSet rendered corresponds to a findAll named query.
Thanks in advance.
Your code doesn't use your named query at all. A named query has a name, and your code doesn't use that name anywhere.
Use
getEntityManager().createNamedQuery("Capacitacao.findByPrefDep", Capacitacao.class)
.setParameter("prefDep", prefDep)
.getResultList();
You could have found that yourself by simply reading the EntityManager javadoc.
I have an entity that I'd like to compare with a subset and determine to select all except the subset.
So, my query looks like this:
Products.Except(ProductsToRemove(), new ProductComparer())
The ProductsToRemove() method returns a List<Product> after it performs a few tasks. So in it's simplest form it's the above.
The ProductComparer() class looks like this:
public class ProductComparer : IEqualityComparer<Product>
{
public bool Equals(Product a, Product b)
{
if (ReferenceEquals(a, b)) return true;
if (ReferenceEquals(a, null) || ReferenceEquals(b, null))
return false;
return a.Id == b.Id;
}
public int GetHashCode(Product product)
{
if (ReferenceEquals(product, null)) return 0;
var hashProductId = product.Id.GetHashCode();
return hashProductId;
}
}
However, I continually receive the following exception:
LINQ to Entities does not recognize
the method
'System.Linq.IQueryable1[UnitedOne.Data.Sql.Product]
Except[Product](System.Linq.IQueryable1[UnitedOne.Data.Sql.Product],
System.Collections.Generic.IEnumerable1[UnitedOne.Data.Sql.Product],
System.Collections.Generic.IEqualityComparer1[UnitedOne.Data.Sql.Product])'
method, and this method cannot be
translated into a store expression.
Linq to Entities isn't actually executing your query, it is interpreting your code, converting it to TSQL, then executing that on the server.
Under the covers, it is coded with the knowledge of how operators and common functions operate and how those relate to TSQL. The problem is that the developers of L2E have no idea how exactly you are implementing IEqualityComparer. Therefore they cannot figure out that when you say Class A == Class B you mean (for example) "Where Person.FirstName == FirstName AND Person.LastName == LastName".
So, when the L2E interpreter hits a method it doesn't recognize, it throws this exception.
There are two ways you can work around this. First, develop a Where() that satisfies your equality requirements but that doesn't rely on any custom method. In other words, test for equality of properties of the instance rather than an Equals method defined on the class.
Second, you can trigger the execution of the query and then do your comparisons in memory. For instance:
var notThisItem = new Item{Id = "HurrDurr"};
var items = Db.Items.ToArray(); // Sql query executed here
var except = items.Except(notThisItem); // performed in memory
Obviously this will bring much more data across the wire and be more memory intensive. The first option is usually the best.
You're trying to convert the Except call with your custom IEqualityComparer into Entity SQL.
Obviously, your class cannot be converted into SQL.
You need to write Products.AsEnumerable().Except(ProductsToRemove(), new ProductComparer()) to force it to execute on the client. Note that this will download all of the products from the server.
By the way, your ProductComparer class should be a singleton, like this:
public class ProductComparer : IEqualityComparer<Product> {
private ProductComparer() { }
public static ProductComparer Instance = new ProductComparer();
...
}
The IEqualityComparer<T> can only be executed locally, it can't be translated to a SQL command, hence the error