What's the correct way to persist an object with an embedded foreign collection? Currently I am using the following but I get an error Could not create data element in dao if I am adding a "zoneplay" object to the customer zonePlays collection when the zonePlay already exists. Is there some sort of upsert method I should use to add to the foreign collection or do I need to check for existance somehow before the insert?
#DatabaseTable
public class Customer {
#DatabaseField(id = true)
public int id;
#ForeignCollectionField(eager = true)
public ForeignCollection<ZonePlay> zonePlays;
#DatabaseField
public String email;
public Customer(String json) {
final JSONArray zonesJson = customerJson.getJSONArray("zoneplays");
this.zonePlays = DatabaseHelper.getInstance(ctx).getCustomerDao().getEmptyForeignCollection("zonePlays");
for (int i = 0; i < numZones; i++) {
final JSONObject rawZone = zonesJson.getJSONObject(i);
ZonePlay zp = new ZonePlay();
zp.id = rawZone.getInt("id");
zp.score = rawZone.getInt("score");
zp.Customer = this;
this.zonePlays.add(zp);
}
}
#DatabaseTable
public class ZonePlay {
#DatabaseField(id = true)
public int id;
#DatabaseField(foreign=true)
public Customer customer;
}
Then I run this
Customer cust = new Customer(client.response);
DatabaseHelper db = DatabaseHelper.getInstance(getApplicationContext());
db.getDao(Customer.class).createOrUpdate(cust);
What's the correct way to persist an object with an embedded foreign collection?
The "correct" way may be to add the element using it's own DAO -- not through the foreign collection. This way you can use the createOrUpdate(...) method:
Dao<ZonePlay, Integer> zoneDao = DatabaseHelper.getInstance(ctx).getZoneDao();
for (int i = 0; i < numZones; i++) {
final JSONObject rawZone = zonesJson.getJSONObject(i);
ZonePlay zp = new ZonePlay();
zp.id = rawZone.getInt("id");
zp.score = rawZone.getInt("score");
zp.Customer = this;
zoneDao.createOrUpdate(zp);
}
I get an error Could not create data element in dao if I am adding a "zoneplay" object to the customer zonePlays collection when the zonePlay already exists.
Right. If you are trying to add a ZonePlay to a Customer's foreign collection, this will try to add to the table. If a ZonePlay already exists in the table then this will throw an exception.
Related
I'm using the BulkExtensions library for EF Core. I have an object that contains a reference to another item example below
Child
public class Location
{
public string Id;
public string Description;
public string Item
}
Parent
public class Parent
{
public Guid Id;
public Location Location;
public string Name;
public string Service;
.....
}
I receive a list of Parent objects to add to my Postgres DB. I have the following code to add the items
List<Parent> parentObjects; // this is being passed in
var locations = _dbcontext.Locations().ToList();
foreach (var item in parentObjects)
{
item.Location = locations.First(x => x.Id == item.Location.Id);
// Additional logic
}
var bulkConfig = new BulkConfig()
{
//IncludeGraph = true,
CalculateStats = true,
PropertiesToIncludeOnUpdate = new List<string> { string.Empty }
};
await _dbContext.BulkInsertOrUpdateAsync(parentObjects, cancellationToken: cancellationToken,
bulkConfig: bulkConfig).ConfigureAwait(false);
await _dbContext.BulkSaveChangesAsync(cancellationToken: cancellationToken).ConfigureAwait(false);
This adds the item to the table but the column for the foreign key locationId is always null. Is there configuration option that I am missing when calling the BulkInsertOrUpdate method?
If I add the IncludeGraph option for BuilkConfig, I get an exception that the Key is not found in the dictionary for the FK column.
I have a class that I am attempting to query by "userid"
#Entity
#IdClass(CollectionPK.class)
#Table(name="collection", schema="mageduelsusers")
public class Collection{
#Id
#Column(name = "userid")
private int userId;
#Id
#Column(name = "cardid")
private int cardId;
...
Id class of
public class CollectionPK implements Serializable{
private int userId;
private int cardId;
public CollectionPK() {
}
...
Query code is
public List<Collection> readCollection(int id) {
List<Collection> collection = null;
Session session = factory.openSession();
Transaction tx = null;
try {
tx = session.beginTransaction();
CriteriaBuilder builder = session.getCriteriaBuilder();
CriteriaQuery<Collection> criteriaQuery = builder.createQuery(Collection.class);
Root<Collection> root = criteriaQuery.from(Collection.class);
ParameterExpression userIdParameter = builder.parameter(Collection.class);
criteriaQuery.where(builder.equal(root.get("userid"), userIdParameter));
Query<Collection> query = session.createQuery(criteriaQuery);
query.setParameter("userid", id);
collection = query.getResultList();
tx.commit();
}
...
Error is
Exception in thread "main" java.lang.IllegalArgumentException: Unable to locate Attribute with the the given name [userid] on this ManagedType [com.panda.userinfo.Collection]
Ideal query would be
Select * from collection where userid = 'userid';
How do I modify to make this work?
Pretty sure error is in the criteria builder section as session.save(). session.get(), and session.delete() all work properly
Update:
Did a little bit of testing and the cause of the issue is definitely root.get("userid") Is there any way to check what Attributes hibernate has for a class?
Update2:
Capitalizing the I in root.get("userId") fixes that error. However both forms still cause an error at query.setParameter("userId", id)
java.lang.IllegalArgumentException: Unable to locate parameter registered with that name [userId]
Update 3:
Figured it out or at least made it functional. Hibernate was renaming things in the background. Solved by printing everything to find the correct parameter name.
for(Parameter<?> p:query.getParameters()) {
System.out.println(p.getName());
}
System.out.println(query.getParameters().size());
Try to correct your query in this way:
CriteriaBuilder builder = session.getCriteriaBuilder();
CriteriaQuery<Collection> criteriaQuery = builder.createQuery(Collection.class);
Root<Collection> root = criteriaQuery.from(Collection.class);
ParameterExpression<Integer> userIdParameter = builder.parameter(Integer.class);
criteriaQuery.where(builder.equal(root.get("userid"), userIdParameter));
List<Collection> collection = session.createQuery(criteriaQuery)
.setParameter("userid", id)
.getResultList();
See also this section of the documentation.
i'm using MondoDB with Morphia 0.105 layer.
My User class is:
#Entity
public class User {
#Id
private ObjectId id = null;
private String userId = null;
private String fullName = null;
#Embedded
private UserType userType = null;
#Embedded
private Set<Rights> rights = new HashSet<Rights>();
and my test class is:
public class Test {
public static void main(String[] args) throws UnknownHostException {
Morphia m = new Morphia();
Datastore ds = m.createDatastore(new MongoClient("localhost"), "test");
m.map(User.class);
User u = new User();
u.setFullName("User Name");
u.setUserId("USERID");
//u.getRights().add(Rights.ADMIN); //NO rights added VS ONE right added
ds.save(u);
u = ds.find(User.class).filter("rights size", 0).get();
System.out.println(u);
System.out.println(u != null);
}
}
I got this unexpected result:
The type(s) for the query/update may be inconsistent; using an instance of type 'java.lang.Integer' for the field 'org.vts.sis2.entities.User.rights' which is declared as 'java.util.Set'
If i uncomment line //u.getRights().add(Rights.ADMIN); that adds to user a right, the query ds.find(User.class).filter("rights size", 1).get() returns the correct result (even if the warning is displayed, but it's a false positive since in my opinion it's correct to compare a result of size operator to an integer)!
What should i do to query users with empty rights list/set field?
Thanks
Try this:
ds.find(User.class).field("rights").sizeEq(0).get()
I'm using EclipseLink to run some Native SQL. I need to return the data into a POJO. I followed the instructions at EclipseLink Docs, but I receive the error Missing descriptor for [Class]
The query columns have been named to match the member variables of the POJO. Do I need to do some additional mapping?
POJO:
public class AnnouncementRecipientsFlattenedDTO {
private BigDecimal announcementId;
private String recipientAddress;
private String type;
public AnnouncementRecipientsFlattenedDTO() {
super();
}
public AnnouncementRecipientsFlattenedDTO(BigDecimal announcementId, String recipientAddress, String type) {
super();
this.announcementId = announcementId;
this.recipientAddress = recipientAddress;
this.type = type;
}
... Getters/Setters
Entity Manager call:
public List<AnnouncementRecipientsFlattenedDTO> getNormalizedRecipientsForAnnouncement(int announcementId) {
Query query = em.createNamedQuery(AnnouncementDeliveryLog.FIND_NORMALIZED_RECIPIENTS_FOR_ANNOUNCEMENT, AnnouncementRecipientsFlattenedDTO.class);
query.setParameter(1, announcementId);
return query.getResultList();
}
I found out you can put the results of a Native Query execution into a List of Arrays that hold Objects. Then one can iterate over the list and Array elements and build the desired Entity objects.
List<Object[]> rawResultList;
Query query =
em.createNamedQuery(AnnouncementDeliveryLog.FIND_NORMALIZED_RECIPIENTS_FOR_ANNOUNCEMENT);
rawResultList = query.getResultList();
for (Object[] resultElement : rawResultList) {
AnnouncementDeliveryLog adl = new AnnouncementDeliveryLog(getAnnouncementById(announcementId), (String)resultElement[1], (String)resultElement[2], "TO_SEND");
persistAnnouncementDeliveryLog(adl);
}
You can only use native SQL queries with a class if the class is mapped. You need to define the AnnouncementRecipientsFlattenedDTO class as an #Entity.
Otherwise just create the native query with only the SQL and get an array of the data back and construct your DTO yourself using the data.
Old question but may be following solution will help someone else.
Suppose you want to return a list of columns, data type and data length for a given table in Oracle. I have written below a native sample query for this:
private static final String TABLE_COLUMNS = "select utc.COLUMN_NAME, utc.DATA_TYPE, utc.DATA_LENGTH "
+ "from user_tab_columns utc "
+ "where utc.table_name = ? "
+ "order by utc.column_name asc";
Now the requirement is to construct a list of POJO from the result of above query.
Define TableColumn entity class as below:
#Entity
public class TableColumn implements Serializable {
#Id
#Column(name = "COLUMN_NAME")
private String columnName;
#Column(name = "DATA_TYPE")
private String dataType;
#Column(name = "DATA_LENGTH")
private int dataLength;
public String getColumnName() {
return columnName;
}
public void setColumnName(String columnName) {
this.columnName = columnName;
}
public String getDataType() {
return dataType;
}
public void setDataType(String dataType) {
this.dataType = dataType;
}
public int getDataLength() {
return dataLength;
}
public void setDataLength(int dataLength) {
this.dataLength = dataLength;
}
public TableColumn(String columnName, String dataType, int dataLength) {
this.columnName = columnName;
this.dataType = dataType;
this.dataLength = dataLength;
}
public TableColumn(String columnName) {
this.columnName = columnName;
}
public TableColumn() {
}
#Override
public int hashCode() {
int hash = 0;
hash += (columnName != null ? columnName.hashCode() : 0);
return hash;
}
#Override
public boolean equals(Object object) {
if (!(object instanceof TableColumn)) {
return false;
}
TableColumn other = (TableColumn) object;
if ((this.columnName == null && other.columnName != null) || (this.columnName != null && !this.columnName.equals(other.columnName))) {
return false;
}
return true;
}
#Override
public String toString() {
return getColumnName();
}
}
Now we are ready to construct a list of POJO. Use the sample code below to construct get your result as List of POJOs.
public List<TableColumn> findTableColumns(String table) {
List<TableColumn> listTables = new ArrayList<>();
EntityManager em = emf.createEntityManager();
Query q = em.createNativeQuery(TABLE_COLUMNS, TableColumn.class).setParameter(1, table);
listTables = q.getResultList();
em.close();
return listTables;
}
Also, don't forget to add in your POJO class in persistence.xml! It can be easy to overlook if you are used to your IDE managing that file for you.
Had the same kind of problem where I wanted to return a List of POJOs, and really just POJOs (call it DTO if you want) and not #Entity annotated Objects.
class PojoExample {
String name;
#Enumerated(EnumType.STRING)
SomeEnum type;
public PojoExample(String name, SomeEnum type) {
this.name = name;
this.type = type;
}
}
With the following Query:
String query = "SELECT b.name, a.newtype as type FROM tablea a, tableb b where a.tableb_id = b_id";
Query query = getEntityManager().createNativeQuery(query, "PojoExample");
#SuppressWarnings("unchecked")
List<PojoExample> data = query.getResultList();
Creates the PojoExample from the database without the need for an Entity annotation on PojoExample. You can find the method call in the Oracle Docs here.
edit:
As it turns out you have to use #SqlResultSetMapping for this to work, otherwise your query.getResultList() returns a List of Object.
#SqlResultSetMapping(name = "PojoExample",
classes = #ConstructorResult(columns = {
#ColumnResult(name = "name", type = String.class),
#ColumnResult(name = "type", type = String.class)
},
targetClass = PojoExample.class)
)
Just put this anywhere under your #Entity annotation (so in this example either in tablea or tableb because PojoExample has no #Entity annotation)
I am using tje JPA criteria API to create an "IN" query. I want to select Courses that are in certain Categories. The Categories are supposed to end up in the IN part of the query.
This is the Course entity. It has a reference to a Category entity, because each Course is in one Category.
#Entity
public class Course implements DomainObject {
private Long id;
private Integer version;
private String name;
private Category category;
#Override
#Id
#GeneratedValue
public Long getId() {
return id;
}
public void setId(Long id) {
this.id = id;
}
#ManyToOne
public Category getCategory() {
return category;
}
public void setCategory(Category category) {
this.category = category;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public Integer getVersion() {
return version;
}
public void setVersion(Integer version) {
this.version = version;
}
}
In my service I want to select Courses that are belong to certain (a list) of Categories.
public List<Course> findCourses(CourseFilter filter) {
CriteriaBuilder criteriaBuilder = entityManager.getCriteriaBuilder();
CriteriaQuery<Course> criteriaQuery = criteriaBuilder.createQuery(Course.class);
Root<Course> root = criteriaQuery.from(Course.class);
List<Predicate> predicateList = new ArrayList<Predicate>();
if (!filter.getCategories().isEmpty()) {
Predicate predicate = root.get(Course_.category).in(filter.getCategories());
predicateList.add(predicate);
}
Predicate[] predicates = new Predicate[predicateList.size()];
predicateList.toArray(predicates);
criteriaQuery.where(predicates);
TypedQuery<Course> typedQuery = entityManager.createQuery(criteriaQuery);
return typedQuery.getResultList();
}
When the query executes on the last line of the method it throws an error:
HTTP Status 500 - Request processing failed; nested exception is
org.springframework.dao.InvalidDataAccessApiUsageException:
org.hibernate.TransientObjectException: object references an unsaved transient instance
save the transient instance before flushing:nl.codebasesoftware.produx.domain.Category;
nested exception is java.lang.IllegalStateException:
org.hibernate.TransientObjectException: object references an unsaved transient instance
save the transient instance before flushing: nl.codebasesoftware.produx.domain.Category
I am not even sure I am using the right way to create an IN query. I think the criteria API is terribly complicated. But before I worry about the IN query I would like to know why Hibernate is throwing this TransientObjectException. The filter.getCategories() call results in actual categories, filled with a primary key id, etc.
Added:
Here is how I get the Category instance that I use to later fetch Courses with. This is also a DAO method that is called via a #Service from a #Controller method.
public Category findByName(String name) {
CriteriaBuilder builder = entityManager.getCriteriaBuilder();
CriteriaQuery<Category> query = builder.createQuery(Category.class);
Root<Category> root = query.from(Category.class);
Predicate predicate = builder.equal(root.get(Category_.urlTitle), name);
query.where(predicate);
TypedQuery<Category> typedQuery = entityManager.createQuery(query);
return getSingleResult(typedQuery);
}
So, Hibernate is telling me I am using Category objects that somehow reference an unsaved entity, but I don't see how. The Category that is returned from this method is just a Category that if fetched by Hibernate. I am not doing anything with it before I send it to the method that fetches Courses.
Here is my the controller method:
#RequestMapping(method = RequestMethod.GET, value = "/{categoryUrlName}")
public String setup(#PathVariable("categoryUrlName") String categoryUrlName, Model model){
// Fetch the category
Category category = categoryService.findByName(categoryUrlName);
// if no category found, throw a 404
if(category == null){
throw new ResourceNotFoundException();
}
// Fetch courses in this category
List<Course> courses = courseService.findCourses(category);
model.addAttribute("courses", courses);
model.addAttribute("category", category);
model.addAttribute("mainContent", "content/category");
return "main";
}
Before executing a query, Hibernate flushes the changes you made to persistent entities in the session. This ensures that the query will search on the latest state of all the entities. Unfortunately, one of the dirty entities that Hibernate tries to flush references a transient entity, and thus can't be flushed, which causes the exception. The exception doesn't come from the query itself, but from the flush before the execution of the query.
You probably did something like the following before executing the query:
Cat cat = em.find(Cat.class, catId); // cat is a persistent persistent entity
cat.setMate(new Mouse()); // the mouse has not been persisted, and cat references it.