美好的一天。我在开始编程之前正在测试我的数据库。在此测试中，我有四个实体：员工，产品， SaleBill 和 SaleBilsDetail 。
ER很简单（我还不能放图像）：
http://i.imgur.com/ZegrAuO.png
比林斯的过程是这样的：
员工
import java.io.Serializable;
import javax.persistence.*;
import java.util.Date;
@Entity
@Table(name="employees")
@NamedQuery(name="Employee.findAll", query="SELECT e FROM Employee e")
public class Employee implements Serializable {
private static final long serialVersionUID = 1L;
@Id
@GeneratedValue(strategy=GenerationType.IDENTITY)
@Column(name="id_employee")
private Integer idEmployee;
private String address;
@Temporal(TemporalType.DATE)
@Column(name="birth_date")
private Date birthDate;
@Temporal(TemporalType.DATE)
@Column(name="created_at")
private Date createdAt;
@Column(name="dni", columnDefinition="bpchar")
private String dni;
private String email;
private String names;
@Column(name="state", columnDefinition="bpchar")
private String state;
private String surnames;
@Temporal(TemporalType.DATE)
@Column(name="updated_at")
private Date updatedAt;
public Employee() {
}
public Integer getIdEmployee() {
return this.idEmployee;
}
public void setIdEmployee(Integer idEmployee) {
this.idEmployee = idEmployee;
}
public String getAddress() {
return this.address;
}
public void setAddress(String address) {
this.address = address;
}
public Date getBirthDate() {
return this.birthDate;
}
public void setBirthDate(Date birthDate) {
this.birthDate = birthDate;
}
public Date getCreatedAt() {
return this.createdAt;
}
public void setCreatedAt(Date createdAt) {
this.createdAt = createdAt;
}
public String getDni() {
return this.dni;
}
public void setDni(String dni) {
this.dni = dni;
}
public String getEmail() {
return this.email;
}
public void setEmail(String email) {
this.email = email;
}
public String getNames() {
return this.names;
}
public void setNames(String names) {
this.names = names;
}
public String getState() {
return this.state;
}
public void setState(String state) {
this.state = state;
}
public String getSurnames() {
return this.surnames;
}
public void setSurnames(String surnames) {
this.surnames = surnames;
}
public Date getUpdatedAt() {
return this.updatedAt;
}
public void setUpdatedAt(Date updatedAt) {
this.updatedAt = updatedAt;
}
}
产品
import java.io.Serializable;
import javax.persistence.*;
import java.math.BigDecimal;
import java.util.Date;
@Entity
@Table(name="products")
@NamedQuery(name="Product.findAll", query="SELECT p FROM Product p")
public class Product implements Serializable {
private static final long serialVersionUID = 1L;
@Id
@GeneratedValue(strategy=GenerationType.IDENTITY)
@Column(name="id_product")
private Integer idProduct;
@Temporal(TemporalType.DATE)
@Column(name="created_at")
private Date createdAt;
private String description;
@Column(name="id_category")
private Integer idCategory;
private String name;
private BigDecimal price;
@Column(name="state", columnDefinition="bpchar")
private String state;
private Short stock;
@Temporal(TemporalType.DATE)
@Column(name="updated_at")
private Date updatedAt;
public Product() {
}
public Integer getIdProduct() {
return this.idProduct;
}
public void setIdProduct(Integer idProduct) {
this.idProduct = idProduct;
}
public Date getCreatedAt() {
return this.createdAt;
}
public void setCreatedAt(Date createdAt) {
this.createdAt = createdAt;
}
public String getDescription() {
return this.description;
}
public void setDescription(String description) {
this.description = description;
}
public Integer getIdCategory() {
return this.idCategory;
}
public void setIdCategory(Integer idCategory) {
this.idCategory = idCategory;
}
public String getName() {
return this.name;
}
public void setName(String name) {
this.name = name;
}
public BigDecimal getPrice() {
return this.price;
}
public void setPrice(BigDecimal price) {
this.price = price;
}
public String getState() {
return this.state;
}
public void setState(String state) {
this.state = state;
}
public Short getStock() {
return this.stock;
}
public void setStock(Short stock) {
this.stock = stock;
}
public Date getUpdatedAt() {
return this.updatedAt;
}
public void setUpdatedAt(Date updatedAt) {
this.updatedAt = updatedAt;
}
}
SaleBill
import java.io.Serializable;
import javax.persistence.*;
import java.util.Date;
import java.util.List;
@Entity
@Table(name="sale_bills")
@NamedQuery(name="SaleBill.findAll", query="SELECT s FROM SaleBill s")
public class SaleBill implements Serializable {
private static final long serialVersionUID = 1L;
@Id
@GeneratedValue(strategy=GenerationType.IDENTITY)
@Column(name="id_sale_bill")
private Integer idSaleBill;
@Column(name="company_name")
private String companyName;
@Column(name="company_ruc", columnDefinition="bpchar")
private String companyRuc;
@Temporal(TemporalType.DATE)
@Column(name="sale_date")
private Date saleDate;
@Column(name="state", columnDefinition="bpchar")
private String state;
@ManyToOne(/*fetch = FetchType.EAGER,*/ optional=false)
@JoinColumn(name="id_employee")
private Employee employee;
@OneToMany(cascade = CascadeType.ALL, /*fetch = FetchType.EAGER,*/ targetEntity = SaleBillsDetail.class)
@JoinColumn(name="id_sale_bill_details")
private List<SaleBillsDetail> saleBillsDetails;
public SaleBill() {
}
public Integer getIdSaleBill() {
return this.idSaleBill;
}
public void setIdSaleBill(Integer idSaleBill) {
this.idSaleBill = idSaleBill;
}
public String getCompanyName() {
return this.companyName;
}
public void setCompanyName(String companyName) {
this.companyName = companyName;
}
public String getCompanyRuc() {
return this.companyRuc;
}
public void setCompanyRuc(String companyRuc) {
this.companyRuc = companyRuc;
}
public Date getSaleDate() {
return this.saleDate;
}
public void setSaleDate(Date saleDate) {
this.saleDate = saleDate;
}
public String getState() {
return this.state;
}
public void setState(String state) {
this.state = state;
}
public Employee getEmployee() {
return this.employee;
}
public void setEmployee(Employee employee) {
this.employee = employee;
}
public List<SaleBillsDetail> getSaleBillsDetails() {
return this.saleBillsDetails;
}
public void setSaleBillsDetails(List<SaleBillsDetail> saleBillsDetails) {
this.saleBillsDetails = saleBillsDetails;
}
public SaleBillsDetail addSaleBillsDetail(SaleBillsDetail saleBillsDetail) {
getSaleBillsDetails().add(saleBillsDetail);
saleBillsDetail.setSaleBill(this);
return saleBillsDetail;
}
public SaleBillsDetail removeSaleBillsDetail(SaleBillsDetail saleBillsDetail) {
getSaleBillsDetails().remove(saleBillsDetail);
saleBillsDetail.setSaleBill(null);
return saleBillsDetail;
}
}
SaleBillsDetail
import java.io.Serializable;
import javax.persistence.*;
@Entity
@Table(name="sale_bills_details")
@NamedQuery(name="SaleBillsDetail.findAll", query="SELECT s FROM SaleBillsDetail s")
public class SaleBillsDetail implements Serializable {
private static final long serialVersionUID = 1L;
@Id
@GeneratedValue(strategy=GenerationType.IDENTITY)
@Column(name="id_sale_bill_details")
private Integer idSaleBillDetails;
@Column(name="cuantity", nullable=false)
private Short cuantity;
@ManyToOne(/*fetch = FetchType.EAGER,*/ optional=false)
@JoinColumn(name="id_product")
private Product product;
@ManyToOne
@JoinColumn(name="id_sale_bill")
private SaleBill saleBill;
public SaleBillsDetail() {
}
public Integer getIdSaleBillDetails() {
return this.idSaleBillDetails;
}
public void setIdSaleBillDetails(Integer idSaleBillDetails) {
this.idSaleBillDetails = idSaleBillDetails;
}
public Short getCuantity() {
return this.cuantity;
}
public void setCuantity(Short cuantity) {
this.cuantity = cuantity;
}
public Product getProduct() {
return this.product;
}
public void setProduct(Product product) {
this.product = product;
}
public SaleBill getSaleBill() {
return this.saleBill;
}
public void setSaleBill(SaleBill saleBill) {
this.saleBill = saleBill;
}
}
测试
import java.util.ArrayList;
import java.util.List;
import javax.persistence.EntityManager;
import javax.persistence.EntityManagerFactory;
import javax.persistence.EntityTransaction;
import javax.persistence.Persistence;
import org.jboss.logging.Logger;
public class Test {
@SuppressWarnings("unchecked")
public static void main(String[] args) {
EntityManagerFactory emf = Persistence
.createEntityManagerFactory("BillingTest");
EntityManager em = null;
EntityTransaction tx = null;
final Logger logger = Logger.getLogger(Test.class.getName());
try {
em = emf.createEntityManager();
tx = em.getTransaction();
tx.begin();
List<Product> products = em.createQuery("SELECT p FROM Product p")
.getResultList();
List<Employee> employees = em.createQuery(
"SELECT e FROM Employee e").getResultList();
SaleBill sale = new SaleBill();
sale.setCompanyName("Centro de entrenamiento animal REX E.I.R.L");
sale.setCompanyRuc("04844013110");
sale.setSaleDate(new java.util.Date());
sale.setState("1");
sale.setEmployee(employees.get(0));
SaleBillsDetail saleDetail = new SaleBillsDetail();
List<SaleBillsDetail> details = new ArrayList<>();
saleDetail.setSaleBill(sale);
saleDetail.setProduct(products.get(0));
saleDetail.setCuantity(Short.valueOf(3 + ""));
details.add(saleDetail);
saleDetail = new SaleBillsDetail();
saleDetail.setSaleBill(sale);
saleDetail.setProduct(products.get(1));
saleDetail.setCuantity(Short.valueOf(5 + ""));
details.add(saleDetail);
sale.setSaleBillsDetails(details);
em.persist(sale);
em.flush();
tx.commit();
} catch (Exception ex) {
logger.warn(ex.getMessage());
System.exit(0);
} finally {
if(em != null) em.close();
if(emf != null) emf.close();
}
}
}
异常消息：
INFO: HHH000037: Columns: [id_product, id_sale_bill_details, id_sale_bill, cuantity]
Hibernate: select product0_.id_product as id_produ1_1_, product0_.created_at as created_2_1_, product0_.description as descript3_1_, product0_.id_category as id_categ4_1_, product0_.name as name5_1_, product0_.price as price6_1_, product0_.state as state7_1_, product0_.stock as stock8_1_, product0_.updated_at as updated_9_1_ from products product0_
Hibernate: select employee0_.id_employee as id_emplo1_0_, employee0_.address as address2_0_, employee0_.birth_date as birth_da3_0_, employee0_.created_at as created_4_0_, employee0_.dni as dni5_0_, employee0_.email as email6_0_, employee0_.names as names7_0_, employee0_.state as state8_0_, employee0_.surnames as surnames9_0_, employee0_.updated_at as updated10_0_ from employees employee0_
Hibernate: insert into sale_bills (company_name, company_ruc, id_employee, sale_date, state) values (?, ?, ?, ?, ?)
Hibernate: insert into sale_bills_details (cuantity, id_product, id_sale_bill) values (?, ?, ?)
Hibernate: insert into sale_bills_details (cuantity, id_product, id_sale_bill) values (?, ?, ?)
Hibernate: update sale_bills_details set id_sale_bill_details=? where id_sale_bill_details=?
Hibernate: update sale_bills_details set id_sale_bill_details=? where id_sale_bill_details=?
mar 05, 2015 10:40:40 AM org.hibernate.engine.jdbc.spi.SqlExceptionHelper logExceptions
WARN: SQL Error: 0, SQLState: 23505
mar 05, 2015 10:40:40 AM org.hibernate.engine.jdbc.spi.SqlExceptionHelper logExceptions
ERROR: ERROR: duplicate key violates unique constraint «pk_sale_bill_details»
Detail: Key is already exists (id_sale_bill_details)=(14).
mar 05, 2015 10:40:40 AM org.hibernate.engine.jdbc.batch.internal.AbstractBatchImpl release
INFO: HHH000010: On release of batch it still contained JDBC statements
mar 05, 2015 10:40:40 AM com.company.billing.model.entities.Test main
WARN: org.hibernate.exception.ConstraintViolationException: could not execute statement
我不明白为什么更新句子：update sale_bills_details设置id_sale_bill_details =？其中id_sale_bill_details =？
感谢您的阅读。我很感激任何帮助。
答案 0 :(得分：0)
删除@JoinColumn并在mappedBy课程中添加SaleBill：
@OneToMany(cascade = CascadeType.ALL,
/*fetch = FetchType.EAGER,*/
targetEntity = SaleBillsDetail.class,
mappedBy="saleBill")
private List<SaleBillsDetail> saleBillsDetails;
@OneToMany（所以@ManyToOne）映射应仅由关系的一方管理。
通过在mappedBy中使用 saleBill ，您告诉Hibernate此关系的所有者是 SaleBillsDetail 类中包含的 saleBill 字段（即从 saleBillsDetails 字段类型中扣除，即List<SaleBillsDetail>）。你只在@Many方面使用@JoinColumn。
在此处阅读更多相关信息：
Can someone please explain mappedBy in hibernate?