Develop Reference

How to connect Hibernate with Postgres in Intelij using Maven? [duplicate]

I have written few codes for inserting data into my SQL database. Actually, I am trying to learn Struts 2 with Hibernate. But, unfortunately I am facing a problem after submitting my form.
I could not find the reason for this error message. My try & catch block throws error like:
Exception in saveOrUpdate() Rollback :org.hibernate.MappingException: Unknown entity: v.esoft.pojos.Employee
Pojo(Employee.java):
#Entity
#Table(name = "employee", catalog = "eventusdb")
public class Employee implements java.io.Serializable {
private Integer empId;
private String name;
private String website;
public Employee() {
}
public Employee(String name, String website) {
this.name = name;
this.website = website;
}
#Id
#GeneratedValue(strategy = IDENTITY)
#Column(name = "emp_id", unique = true, nullable = false)
public Integer getEmpId() {
return this.empId;
}
public void setEmpId(Integer empId) {
this.empId = empId;
}
#Column(name = "name", nullable = false)
public String getName() {
return this.name;
}
public void setName(String name) {
this.name = name;
}
#Column(name = "website", nullable = false, length = 65535)
public String getWebsite() {
return this.website;
}
public void setWebsite(String website) {
this.website = website;
}
}
also having Employee.hbm.xml:
<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
<!-- Generated Sep 10, 2013 4:29:04 PM by Hibernate Tools 3.4.0.CR1 -->
<hibernate-mapping>
<class name="v.esoft.pojos.Employee" table="employee" catalog="eventusdb">
<id name="empId" type="java.lang.Integer">
<column name="emp_id" />
<generator class="identity" />
</id>
<property name="name" type="string">
<column name="name" not-null="true" />
</property>
<property name="website" type="string">
<column name="website" length="65535" not-null="true" />
</property>
</class>
</hibernate-mapping>

If the entity isn't mapped, you should inspect the hibernate configuration. Hibernate is ORM framework used to map pojos (entities) to the database schema objects. You didn't configure or hibernate couldn't find mapping for the object Employee. The configuration file is hibernate.cfg.xml should contain the mapping to the resource Employee.hbm.xml. Suppose this file is in the same folder as Employee class. Then the mapping will be
<mapping resource="v/esoft/pojos/Employee.hbm.xml"/>
Another approach if you used an annotation based configuration, then you should use class attribute to map to the pojo that contains Hibernate/JPA annotations.
<mapping class="v.esoft.pojos.Employee"/>
Note, annotation based Configuration might be different depending on version of Hibernate and may require additional libraries.

One object from two tables

I have two tables and want to map them to one object with Hibernate.
The reason for both tables is in the past and I wont change the frontend, which access data like this.
I have Table Event (Event_ID, Preview, img) and Event_Details (ID, Event_ID, content).
I prepare one class in Java:
public class Event {
private int event_ID;
private String preview;
private String img;
private String content;
//Getter and Setter
}
and following XML mapping file:
<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
<!-- Generated 16.03.2016 20:33:10 by Hibernate Tools 3.5.0.Final -->
<hibernate-mapping>
<class name="de.data.events.Event" table="ev1_event">
<id name="id" type="int">
<column name="Event_ID" />
<generator class="assigned" />
</id>
<property name="preview" type="java.lang.String">
<column name="ev1_preview" />
</property>
<property name="img" type="java.lang.String">
<column name="ev1_img" />
</property>
</class>
<class name="de.data.events.Event" table="pb1_event">
<id name="id" type="int">
<column name="id" />
<generator class="assigned" />
</id>
//some properties
</class>
The part, where I have to join table1 to table2 is missing. But I didn´t found a way to fix my problem.

First, you'd have your Hibernate entities. Yours are Event and EventDetail, but for fun, let's go with Person and Address in this example. The key here is that you need a one-to-one or many-to-one relationship between your tables. Otherwise, your resultset will come out weird (more on that later).
#Entity
#Table(name = "PERSON")
public class Person {
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
#Column(name = "PERSON_ID")
public Integer id;
#Column(name = "NAME")
public String name;
#Column(name = "HOME_ADDRESS_ID")
public Integer homeAddressId;
#Column(name = "TEMP_ADDRESS_ID")
public Integer tempAddressId;
// . . . other fields,getters,setters
}
#Entity
#Table(name = "ADDRESS")
public class Address {
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
#Column(name = "ADDRESS_ID")
public Integer id;
#Column(name = "STREET")
public String street;
#Column(name = "CITY")
public String city;
// . . . other fields,getters,setters
}
Then you'd have your target FlatObject POJO with the a constructor that will build it appropriately:
public class FlatObject {
public final String name;
public final String homeStreet;
public final String homeCity;
public final String tempStreet;
public final String tempCity;
public FlatEntity(String name, String homeStreet, String homeCity, String tempStreet, String tempCity) {
this.name = name;
this.homeStreet = homeStreet;
this.homeCity = homeCity;
this.tempStreet = tempStreet;
this.tempCity = tempCity;
}
// . . . other fields,getters
}
Finally, you'd leverage those objects with a Hibernate HQL SELECT where you join Person and Address and use their fields to construct a new FlatEntity:
SELECT new FlatEntity(p.name, ha.homeStreet, ha.homeCity, ta.tempStreet, ta.tempCity)
FROM
Person p, Address ha, Address ta
WHERE
p.homeAddressId = ha.id
and p.tempAddressId = ta.id
As you can see, the HQL statment will join Person to Address twice: once for the home address and once for the temp address.
The same will hold true in your case. So in your case, if you're joining Event e, EventDetail ed WHERE e.id = ed.eventId, just be sure there's only one detail row per Event. Otherwise you'll get multiple rows when you have more than one details or you'll drop rows (because of the inner join) when an event has no details.

Repeated column in mapping for entity (should be mapped with insert="false" update="false") [duplicate]

There is a mapping exception for a particular entity.
Cant figure out from where the problem is arising.
I checked all the mappings 3 times from start to end.
Still i am getting a Mapping Exception.
Email to employee is mapped only once.
but still it is reporting the error repeated mapping
Error is:
Caused by: org.hibernate.MappingException: Repeated column in mapping for entity: com.cluster.entity.Email column: EMPLOYEE_ID (should be mapped with insert="false" update="false")
at org.hibernate.mapping.PersistentClass.checkColumnDuplication(PersistentClass.java:680)
at org.hibernate.mapping.PersistentClass.checkPropertyColumnDuplication(PersistentClass.java:702)
at org.hibernate.mapping.PersistentClass.checkColumnDuplication(PersistentClass.java:724)
at org.hibernate.mapping.PersistentClass.validate(PersistentClass.java:477)
at org.hibernate.mapping.RootClass.validate(RootClass.java:268)
at org.hibernate.cfg.Configuration.validate(Configuration.java:1287)
at org.hibernate.cfg.Configuration.buildSessionFactory(Configuration.java:1729)
at org.hibernate.cfg.Configuration.buildSessionFactory(Configuration.java:1775)
at com.cluster.util.HibernateUtil.<clinit>(HibernateUtil.java:16)
... 1 more
Email Pojo
package com.cluster.entity;
public class Email {
private int intEmailID;
private String strEmailName;
//many to one
private EmailType emailType;
//many to one
private Employee employee;
public int getIntEmailID() {
return intEmailID;
}
public void setIntEmailID(int intEmailID) {
this.intEmailID = intEmailID;
}
public String getStrEmailName() {
return strEmailName;
}
public void setStrEmailName(String strEmailName) {
this.strEmailName = strEmailName;
}
public EmailType getEmailType() {
return emailType;
}
public void setEmailType(EmailType emailType) {
this.emailType = emailType;
}
public Employee getEmployee() {
return employee;
}
public void setEmployee(Employee employee) {
this.employee = employee;
}
}
email.hbm.xml
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE hibernate-mapping PUBLIC
'-//Hibernate/Hibernate Mapping DTD 3.0//EN'
'http://www.hibernate.org/dtd/hibernate-mapping-3.0.dtd'>
<hibernate-mapping package="com.cluster.entity" >
<class name="Email" table="EMAIL">
<id name="intEmailID" column="EMAIL_ID">
<generator class="sequence">
<param name="sequence">EMAIL_ID_SEQ</param>
</generator>
</id>
<property name="strEmailName" column = "EMAIL_NAME"/>
<many-to-one name="employee" column="EMPLOYEE_ID" not-null = "true" class = "Employee"/>
<many-to-one name="emailType" column="EMAIL_TYPE_ID" not-null = "true" class = "EmailType"/>
</class>
</hibernate-mapping>
Related Script
CREATE TABLE EMPLOYEE
(
EMPLOYEE_ID NUMBER NOT NULL,
FIRSTNAME VARCHAR2(20 BYTE) NOT NULL,
LASTNAME VARCHAR2(20 BYTE) NOT NULL,
DATE_OF_BIRTH VARCHAR2(20 BYTE) NOT NULL,
SALARY VARCHAR2(10 BYTE) NOT NULL,
DEPARTMENT_ID NUMBER NOT NULL
);
CREATE TABLE EMAIL
(
EMAIL_ID NUMBER NOT NULL,
EMAIL_NAME VARCHAR2(40 BYTE) NOT NULL,
EMPLOYEE_ID NUMBER NOT NULL,
EMAIL_TYPE_ID NUMBER NOT NULL
);
CREATE TABLE EMAIL_TYPE
(
EMAIL_TYPE_ID NUMBER NOT NULL,
EMAIL_TYPE_NAME VARCHAR2(40 BYTE) NOT NULL
);
ALTER TABLE EMPLOYEE ADD
(
CONSTRAINT PK_EMPLOYEE_ID
PRIMARY KEY (EMPLOYEE_ID)
);
ALTER TABLE EMAIL_TYPE ADD
(
CONSTRAINT PK_EMAIL_TYPE_ID
PRIMARY KEY (EMAIL_TYPE_ID)
);
ALTER TABLE EMAIL ADD
(
CONSTRAINT PK_EMAIL_ID
PRIMARY KEY (EMAIL_ID)
);
ALTER TABLE EMAIL ADD
(
CONSTRAINT FK_EMAIL_EMPLOYEE_ID
FOREIGN KEY (EMPLOYEE_ID)
REFERENCES EMPLOYEE (EMPLOYEE_ID)
);
ALTER TABLE EMAIL ADD
(
CONSTRAINT FK_EMAIL_EMAIL_TYPE_ID
FOREIGN KEY (EMAIL_TYPE_ID)
REFERENCES EMAIL_TYPE (EMAIL_TYPE_ID)
);
Email to employee is mapped only once.
but still it is reporting the error repeated mapping

have you set the collection in Employee as inverse?
<bag name="emails" inverse="true">
<key column="EMPLOYEE_ID" not-null="true">
...
</bag>

For those who are using annotations to solve this, the classes should look like this:
#Entity
public class Email {
#Id
#GeneratedValue(strategy=GenerationType.SEQUENCE)
private int intEmailID;
#Column(insertable = false, updatable = false)
private int employeeId;
#ManyToOne
private EmailType emailType;
#ManyToOne
#JoinColumn(name="employeeId")
private Employee employee;
// Getters and Setter
}
#Entity
public class Employee {
#Id
private int id;
#OneToMany(cascade = {CascadeType.ALL}, mappedBy="employeeId")
#PrimaryKeyJoinColumn
private List<Email> emailList;
public void setEmailList(List<Email> emailList) {
this.emailList = emailList
}
public List<Email> getEmailList() {
return emailList;
}
// Rest of getters and setters
}

I think you have mapped Employee to Email using oneToMany relation. If yes its nothing wrong but you have to make sure you can insert and update only in one direction
should be mapped with insert="false" update="false" in Employee

Hibernate won't create table even though it shows in the sql

Hibernate won't create a specific table called "Product", even though it shows the create table command in the sql.
Category table gets created just fine...
These are classes ;
** BaseObject.java **
#MappedSuperclass
public class BaseObject implements Serializable
{
public static final long serialVersionUID = 1L;
#Id
#GeneratedValue
private Long id;
public Long getId() {
return id;
}
public void setId(Long id) {
this.id = id;
}
}
Category.java
#Entity
public class Category extends BaseObject {
private String name;
#OneToMany(fetch=FetchType.LAZY,mappedBy="category",orphanRemoval=true)
private List<Product> products;
#OneToOne(optional=true)
private Category parent;
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public List<Product> getProducts() {
return products;
}
public void setProducts(List<Product> products) {
this.products = products;
}
public Category getParent() {
return parent;
}
public void setParent(Category parent) {
this.parent = parent;
}
}
Product.java
#Entity
public class Product extends BaseObject{
#ManyToOne
private Category category;
private String jargonCode;
private int order;
private String dataTableJson;
public Category getCategory() {
return category;
}
public void setCategory(Category category) {
this.category = category;
}
public String getDataTableJson() {
return dataTableJson;
}
public void setDataTableJson(String dataTableJson) {
this.dataTableJson = dataTableJson;
}
public String getJargonCode() {
return jargonCode;
}
public void setJargonCode(String jargonCode) {
this.jargonCode = jargonCode;
}
public int getOrder() {
return order;
}
public void setOrder(int order) {
this.order = order;
}
}
Spring Conf
<jee:jndi-lookup id="dataSource" jndi-name="${jdni.dataSource}"
expected-type="javax.sql.DataSource" />
<bean id="sessionFactory"
class="org.springframework.orm.hibernate4.LocalSessionFactoryBean">
<property name="dataSource" ref="dataSource" />
<property name="annotatedClasses">
<list>
<value>com.dataCollector.pojo.Category</value>
<value>com.dataCollector.pojo.Product</value>
</list>
</property>
<property name="hibernateProperties">
<props>
<prop key="hibernate.dialect">${hibernate.dialect}</prop>
<prop key="hibernate.show_sql">${hibernate.showSql}</prop>
<prop key="hibernate.hbm2ddl.auto">${hibernate.action}</prop>
</props>
</property>
</bean>
The product won't get created. The strange thing is, it puts the create table command in the sql...
Hibernate: alter table Category drop foreign key FK_p6elut499cl32in8b8j8sy2n4
Hibernate: alter table Product drop foreign key FK_b7afq93qsn7aoydaftixggf14
Hibernate: drop table if exists Category
Hibernate: drop table if exists Product
Hibernate: create table Category (id bigint not null auto_increment, name varchar(255), parent_id bigint, primary key (id))
Hibernate: create table Product (id bigint not null auto_increment, dataTableJson varchar(255), jargonCode varchar(255), order integer not null, category_id bigint, primary key (id))
Hibernate: alter table Category add constraint FK_p6elut499cl32in8b8j8sy2n4 foreign key (parent_id) references Category (id)
Hibernate: alter table Product add constraint FK_b7afq93qsn7aoydaftixggf14 foreign key (category_id) references Category (id)
I really don't understand why.. I use MySQL server.
And I've tried setting hibernate.hbm2ddl.auto to both create and create-drop. But nothing. Can anyone help me ?

Try to change the 'order' column name, is a reserved word, formally the sql is correct by I had a similar issue calling a column 'user' instead of 'userId'

Missing sequence or table: hibernate_sequence

I am new to hibernate and postgres. Actually I am trying to map potgres database using Hibernate. This is my table stucture in postgresql
CREATE TABLE employee
(
id serial NOT NULL,
firstname character varying(20),
lastname character varying(20),
birth_date date,
cell_phone character varying(15),
CONSTRAINT employee_pkey PRIMARY KEY (id )
)
I am trying to add a record to the database using the following code
System.out.println("******* WRITE *******");
Employee empl = new Employee("Jack", "Bauer", new Date(System.currentTimeMillis()), "911");
empl = save(empl);
//This is the save function
private static Employee save(Employee employee) {
SessionFactory sf = HibernateUtil.getSessionFactory();
Session session = sf.openSession();
session.beginTransaction();
int id = (Integer) session.save(employee);
employee.setId(id);
session.getTransaction().commit();
session.close();
return employee;
}
When I execute the code I am getting the following error
org.hibernate.HibernateException: Missing sequence or table: hibernate_sequence
Exception in thread "main" java.lang.ExceptionInInitializerError
at org.tcs.com.Hibernate.HibernateUtil.buildSessionFactory(HibernateUtil.java:18)
at org.tcs.com.Hibernate.HibernateUtil.<clinit>(HibernateUtil.java:8)
at org.tcs.com.Hibernate.MainApp.list(MainApp.java:51)
at org.tcs.com.Hibernate.MainApp.main(MainApp.java:17)
Caused by: org.hibernate.HibernateException: Missing sequence or table: hibernate_sequence
at org.hibernate.cfg.Configuration.validateSchema(Configuration.java:1282)
at org.hibernate.tool.hbm2ddl.SchemaValidator.validate(SchemaValidator.java:155)
at org.hibernate.internal.SessionFactoryImpl.<init>(SessionFactoryImpl.java:498)
at org.hibernate.cfg.Configuration.buildSessionFactory(Configuration.java:1740)
at org.hibernate.cfg.Configuration.buildSessionFactory(Configuration.java:1778)
at org.tcs.com.Hibernate.HibernateUtil.buildSessionFactory(HibernateUtil.java:15)
... 3 more
I have the sequence called "employee_id_seq" in my database. But I dont know why the database is looking for hibernate_seq. Could someone explain the error and the reason.
Thanks in advance!
Added info
This is my employee class
import java.sql.Date;
public class Employee {
private int id;
private String firstname;
private String lastname;
private Date birthDate;
private String cellphone;
public Employee() {
}
public Employee(String firstname, String lastname, Date birthdate, String phone) {
this.firstname = firstname;
this.lastname = lastname;
this.birthDate = birthdate;
this.cellphone = phone;
}
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getFirstname() {
return firstname;
}
public void setFirstname(String firstname) {
this.firstname = firstname;
}
public String getLastname() {
return lastname;
}
public void setLastname(String lastname) {
this.lastname = lastname;
}
public Date getBirthDate() {
return birthDate;
}
public void setBirthDate(Date birthDate) {
this.birthDate = birthDate;
}
public String getCellphone() {
return cellphone;
}
public void setCellphone(String cellphone) {
this.cellphone = cellphone;
}
}

In your domain or Model object annotate the id field as below and it should work. For me the GenerationType.AUTO failed
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
private int id;

You haven't posted the important bit: the Employee class.
But my guess is that your Employee class is using #GeneratedValue() without specifying the sequence to use. So, Hibernate uses its default name: hibernate_sequence.
You can supply a sequence name as part of the GeneratedValue annotation. eg.
#GeneratedValue(strategy=SEQUENCE, generator="employee_id_seq")

Simple solution :
create hibernate_sequence table as :
"create sequence <schema>.hibernate_sequence"

If you encounter this with Spring Boot or Spring boot/Hibernate Migration then potentially you can try the following
Quote:
By default, Hibernate generates key from hibernate_sequence table, we
can disable it by setting this hibernate.use-new-id-generator-mappings
to false.
application.properties
spring.datasource.url=jdbc:mysql://localhost:3306/test
spring.datasource.username=mkyong
spring.datasource.password=password
spring.jpa.hibernate.use-new-id-generator-mappings=false

If you don't use annotation you should change YourClass.hbm.xml file.
Your ID section should be:
<id name="id" type="int" column="id">
<generator class="sequence">
<param name="sequence">employee_id_seq</param>
</generator>
</id>
File sample:
<?xml version="1.0" encoding="utf-8"?>
<!DOCTYPE hibernate-mapping PUBLIC
"-//Hibernate/Hibernate Mapping DTD//EN"
"http://www.hibernate.org/dtd/hibernate-mapping-3.0.dtd">
<hibernate-mapping>
<class name="Employee" table="EMPLOYEE">
<meta attribute="class-description">
This class contains the employee detail.
</meta>
<id name="id" type="int" column="id">
<generator class="sequence">
<param name="sequence">employee_id_seq</param>
</generator>
</id>
<property name="firstName" column="first_name" type="string"/>
<property name="lastName" column="last_name" type="string"/>
<property name="salary" column="salary" type="int"/>
</class>
</hibernate-mapping>

You can do two things.
One is to just manually create a blank hibernate_sequence table postgresql.
Two, most likely there is a conflict with the user account permissions not allowing grails to create that table.

Apart from creating the table hibernate_sequence which has a column next_val
you can also set quarkus.hibernate-orm.database.generation = drop-and-create. Note this will delete all the record in you database.

For me, what was causing this error was the wrong version of the MySql.Data library.
I had a version 6.9.6.0 defined in the web.config and yet the actual referenced version was older.
I just commented out :
<system.data>
<DbProviderFactories>
<remove invariant="MySql.Data.MySqlClient" />
<add name="MySQL Data Provider" invariant="MySql.Data.MySqlClient" description=".Net Framework Data Provider for MySQL" type="MySql.Data.MySqlClient.MySqlClientFactory, MySql.Data, Version=6.9.6.0, Culture=neutral, PublicKeyToken=c5687fc88969c44d" />
</DbProviderFactories>
</system.data>