Is there any way to get the field name in an entity using column name.
#Table(name = "ESTABLISHMENT")
public class Establishment implements Serializable {
/**
*
*/
private static final long serialVersionUID = 1L;
#Id
#Column(name = "EST_CODE")
private Long code;
#Column(name = "W_CODE")
private Long wCode;
}
//service
I have W_CODE name is there any way to get the field name in the entity. Here its wCode.
I want to use that to create a custom JPQL query.
You can parse the column annotations:
for (Field field : entity.getClass().getDeclaredFields()) {
Column column = field.getAnnotation(Column.class);
if (column != null) {
columnNames.add(column.name());
}
}
You can get the Column name list using your Entity or Model. What we need is #Column, which should be used in your Entity. You will get all the details which you have specified in #Column. All the parameters are optional, although it is good to define all.
#Column(name, columnDefinition, insertable, length, nullable,
precision, scale, table, unique, updatable)
We can get all fields declared in Entity by User.class.getDeclaredFields() ( in general ModelName.class.getDeclaredFields()). After getting all feilds we can get particular Column using field.getAnnotation(Column.class) we can also get all the details specified in #Column as below
Columns: #javax.persistence.Column(nullable=false, precision=2, unique=true, name=id, length=2, scale=1, updatable=false, columnDefinition=, table=, insertable=true)
Columns: #javax.persistence.Column(nullable=true, precision=0, unique=false, name=client_id, length=255, scale=0, updatable=true, columnDefinition=, table=, insertable=true)
Columns: #javax.persistence.Column(nullable=true, precision=0, unique=false, name=firstname, length=255, scale=0, updatable=true, columnDefinition=, table=, insertable=true)
Columns: #javax.persistence.Column(nullable=true, precision=0, unique=false, name=lastname, length=255, scale=0, updatable=true, columnDefinition=, table=, insertable=true)
create endPoint or method as per requirement
#GetMapping(value= "/columns/name")
public List<String> tableColumnsName()
{
List<String> Columns = new ArrayList<String>();
Field[] fields = User.class.getDeclaredFields();
for (Field field : fields) {
Column col = field.getAnnotation(Column.class);
if (col != null) {
Columns.add(col.name());
System.out.println("Columns: "+col);
}
}
return Columns;
}
Related
The user can search for products if any product shown in the result exists in the user_favorites table so the show flag tells the front-end this product was added for this user by user_id and product_id. with spring boot and spring data.
My Entity :
#Id
#Column(name = "catId")
private Integer catId;
#Column(name = "cat_no")
private String catNo;
#Column(name = "cat_sn")
private String catSn;
#Column(name = "doc_ref")
private String docRef;
#Column(name = "user_id")
private Integer userId;
#Column(name = "updated_at")
private String updatedAt;
#Column(name = "created_at")
private String createdAt;
I tried that using #Formula but nothing happing always returns null. and if it's done by #Formula how can i add parameters to #Formula
#Formula(value = "SELECT count(*) as checker FROM fb_user_favorites WHERE cat_id = 34699 AND user_id = '52') ")
#Transient
private String checker;
#Transient is part of JPA spec. In Hibernate fields marked with this annotation just simply ignored/excluded from any JPA engine/runtime logic.
#Formula is part of Hibernate. Fields, marked with it, don't persisted by Hibernate (first argument do not use #Transient as redundant), values are calculated by provided SQL when executing query for entity.
So for Hibernate to see this fields, they should not be excluded by #Transient
TL;DR remove #Transient annotation
Complicated but fast working way.
Adding isFavorite field to the entity:
#Transient
private boolean isFavorite;
Create an entity linking Product and User:
public class ProductFavorite {
#Id
#GeneratedValue(strategy = IDENTITY)
private Long id;
#ManyToOne(optional = false, fetch = LAZY)
private Product product;
#ManyToOne(optional = false, fetch = LAZY)
private User user;
}
Then create a repository with a method to find the user's favorite products:
#Repository
public interface ProductLikeRepository extends JpaRepository<ProductFavorite, Long> {
#Query("select f.product.id from ProductFavorite f where f.product in ?1 and f.user = ?2")
Set<Integer> findProductIdsByIdsAndUser(List<Product> products, User user);
}
And at the end, write a method that will fill in the isFavorite field:
public void fillFavorite(List<Product> products, User user) {
if (products.isEmpty()) {
return;
}
var likedIds = favoriteRepository.findProductIdsByIdsAndUser(products, user);
for (Product product : products) {
product.setFavorite(likedIds.contains(product.getId()));
}
}
You need to call it manually:
List<Product> products = productRepository.findAll();
fillFavorite(products, currentUser());
I am trying to map only certain fields to the entity object using a native SQL query :
#NamedNativeQuery(name = "CustomerEntity.findOnlyNameAndPhoneFromCustomer", query = "select customer_name, customer_email from customer",
resultSetMapping = "nativeMapping")
#SqlResultSetMappings(value = {
#SqlResultSetMapping(name = "nativeMapping",
entities = {
#EntityResult(
entityClass = CustomerEntity.class,
fields = {
#FieldResult(name = "name", column = "customer_name"),
#FieldResult(name = "email", column = "customer_email")
}
)})})
#Entity
class CustomerEntity {
//getter and setter fields
#Column(name="customer_name")
private String name;
#Column(name="customer_email")
private String email;
#Column(name="address")
private String adddress;
#Id
#GeneratedValue(generator = "uuid2")
#GenericGenerator(name = "uuid2", strategy = "uuid2")
#Access(AccessType.PROPERTY)
#Column(columnDefinition = "VARCHAR(36)", name = "customer_guid")
#Type(type = "uuid-char")
private UUID guid;
#Embedded
private AuditFields audit;
}
Repository:
#Query(nativeQuery = true)
List<CustomerEntity> findOnlyNameAndPhoneFromCustomer();
I am not trying to map all the fields that are present in the customer table to CustomerEntity, I am only projecting certain fields.
This is giving me errors like:
17:44:37.841 [ERROR] o.h.e.j.s.SqlExceptionHelper - The column name address2_6_0_ is not valid.
There is no column called address2_6_0_ in my table, but there is a column called address, why is the address column being renamed and referenced here ?
I am only referencing customer_name and customer_email.
What is going on ?
Thanks.
entities is for "mapping to entities".
#EntityResult:
If this annotation is used, the SQL statement should select all of the columns that are mapped to the entity object.
Therefore, you should use classes and #ConstructorResult for "mapping to DTOs".
#NamedNativeQuery(name = "CustomerEntity.findOnlyNameAndPhoneFromCustomer",
query = "select customer_name, customer_email from customer",
resultSetMapping = "nativeMapping")
#SqlResultSetMappings(value = {
#SqlResultSetMapping(name = "nativeMapping",
classes = #ConstructorResult(columns = { #ColumnResult(name = "customer_name"), #ColumnResult(name = "customer_email") },
targetClass = CustomerEntity.class)) })
#Entity
public class CustomerEntity {
public CustomerEntity() {
}
public CustomerEntity(String name, String email) {
this.name = name;
this.email = email;
}
...
}
I have table/entity which has varchar(255) field that can store values of multiple data types and type field which indicates what kind of value type it is. I want to perform join only if data type is of certain value ie. document.
Example:
#Entity
#Table(name = "ACT_HI_DETAIL")
public class TaskDetailsVariable implements Serializable {
#Id
#Column(name = "ID_")
private String id;
#Column(name = "TEXT_")
private String value;
#Column(name = "VAR_TYPE_")
private String type;
#ManyToOne
#JoinColumn(name = "TEXT_")
#WhereJoinTable(clause = "VAR_TYPE_ = 'document'") // this doesn't work
private Document document; // this should be joined only if type is document
}
When I try the example above, I get the error because it tries to join all LONG_ values. I have also tried #JoinFormula and #Where.
I have #NamedQuery. I want to add a lot of different filters to the query as per condition at runtime. There is another concept of #Filter in Hibernate. can this concept be a merge to have a combined result?
suppose I have
#NamedQuery(name="Users.someUsers",query="select u from Users where firstname='bob'")
suppose I want to filter the result according to some other parameter.
can I add #Filter that can do the trick?
supposed I want to an add age filer or a place filter over the existing Users.someUsers by enabling the corresponding filter on the underlying hibernate session?
I suppose you want to define named queries and filters at entity level and expect named queries to have filters which you defined.
I wrote a test for it:
#Entity
#Table(name = "DEPARTMENT")
#NamedQueries({#NamedQuery(name=DepartmentEntity.GET_DEPARTMENT_BY_ID, query=DepartmentEntity.GET_DEPARTMENT_BY_ID_QUERY),})
#FilterDef(name="deptFilter", parameters={#ParamDef( name="name", type="string")})
#Filters( {#Filter(name="deptFilter", condition=":name = name")})
public class DepartmentEntity implements Serializable {
static final String GET_DEPARTMENT_BY_ID_QUERY = "from DepartmentEntity d where d.id = :id";
public static final String GET_DEPARTMENT_BY_ID = "GET_DEPARTMENT_BY_ID";
private static final long serialVersionUID = 1L;
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
#Column(name = "ID", unique = true, nullable = false)
private Integer id;
#Column(name = "NAME", unique = true, nullable = false, length = 100)
private String name;
public Integer getId() {
return id;
}
public void setId(Integer id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
}
Now you can use both like this:
Session session = (Session) entityManager.getDelegate();
Filter filter = session.enableFilter("deptFilter");
filter.setParameter("name", name);
return (DepartmentEntity) session.getNamedQuery(DepartmentEntity.GET_DEPARTMENT_BY_ID)
.setParameter("id", id)
.uniqueResult();
Query generated by hibernate:
select department0_.ID as ID1_3_, department0_.NAME as NAME2_3_ from DEPARTMENT department0_ where ? = department0_.name and department0_.ID=?
You will need to add filters to session and then create named query. If this doesn't cover your use case then post example exactly what you want to acheive.
This is what CriteriaQuery is built for. It allows you to create queries at runtime.
Avoid using named queries for queries which you want to build at runtime based on user input.
Example
CriteriaBuilder builder = entityManager.getCriteriaBuilder();
CriteriaQuery<EntityType> criteria = builder.createQuery(EntityType.class);
Root<EntityType> root = criteria.from(EntityType.class);
criteria.where(
builder.equal(root.get("owner"), "something")
);
// Any conditions can be added to criteria here ar runtime based on user input
List<Topic> topics = entityManager
.createQuery(criteria)
.getResultList();
Named queries are precompiled at EntityManagerFactory startup, so they add performance benefits as long as queries are static, but for dynamic queries consider using CriteriaQueries
is it possible to query values from set? for example,
public class Employee implements Serializable {
/** Person ID (indexed). */
#QuerySqlField(index = true)
private long id;
/** Department ID (indexed). */
#QuerySqlField(index = true)
private Set deptIds;
/** First name (not-indexed). */
#QuerySqlField
private String firstName;
/** Last name (not indexed). */
#QuerySqlField
private String lastName;
}
now i want to get all employee for one particular department.
It is possible with Scan queries, but not possible with SQL queries.
Looks like you use SQL queries. In this case you have to think in terms of relational databases. There is a many-to-many relationship between Employee and Department, so you have to add a Junction Table.
public class EmployeeDepartment implements Serializable {
/** Person ID (indexed). */
#QuerySqlField(index = true)
private long personId;
/** Department ID (indexed). */
#QuerySqlField(index = true)
private long deptId;
}
After that you can do a three way join to find employees for a particular department.