java - Hibernate 在 PostgreSQL 中使用驼峰格式的主键

Question

我有以下结构的表格

CREATE TABLE "tblChecks"
(
  "checkId" serial NOT NULL,
  "bankId" text,
  "checkNumber" text,
  amount numeric(30,2)
)

我使用 hibernate 在数据库上进行事务我的问题是 随着数据的插入。我已经映射了我的 具有以下注释的模型

@Entity
@Table(name = "\"tblChecks\"")
public class Check {

    /* Integereger values*/
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    @Column(name = "\"checkId\"")
    private Integer checkId;

    @Column(name = "amount")
    private Double amount;

    /* String  values*/
    @Column(name = "\"bankId\"")
    private String bankId;

    @Column(name = "\"checkNumber\"")
    private String checkNumber;

在我的插入方法中发生了错误

ERROR: org.hibernate.engine.jdbc.spi.SqlExceptionHelper - The column name "checkId" was not found in this ResultSet.

我的问题是如何使用 Postgres 修复主键上的这些错误。将列名更改为 checkid 将修复错误，但我不能这样做，因为这些表已在当前系统中使用。

Answer 1

我在您的 POJO 中发现的第一个错误是您在 PostgresSQL 中使用了自动递增。 hibernate 3.x 到 4.2 不支持此功能。因此，您无法在数据库中插入记录，并且可能会出现所谓的异常 org.hibernate.exception.SQLGrammarException: could not retrieve generated id after insert:
您可以使用 serial 或 sequence 代替它。 Serial Doc

更新的 POJO 类:我使用序列生成实体 ID 并实现了与 auto_increment 相同的功能。

package stack.filter;

import java.io.Serializable;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.SequenceGenerator;
import javax.persistence.Table;

@Entity
@Table(name = "\"tblChecks\"")
public class Check implements Serializable
{

    private static final long serialVersionUID = 1L;

    /* Integereger values */

    @Id
    @GeneratedValue(strategy = GenerationType.SEQUENCE, generator="checkId_seq")
    @SequenceGenerator(name="checkId_seq", sequenceName="checkId_seq", allocationSize=1)
    @Column(name = "\"checkId\"")
    private Integer checkId;

    @Column(name = "amount")
    private Double amount;

    /* String values */
    @Column(name = "\"bankId\"")
    private String bankId;

    @Column(name = "\"checkNumber\"")
    private String checkNumber;

    public Integer getCheckId()
        {
            return checkId;
        }

    public void setCheckId(Integer checkId)
        {
            this.checkId = checkId;
        }

    public Double getAmount()
        {
            return amount;
        }

    public void setAmount(Double amount)
        {
            this.amount = amount;
        }

    public String getBankId()
        {
            return bankId;
        }

    public void setBankId(String bankId)
        {
            this.bankId = bankId;
        }

    public String getCheckNumber()
        {
            return checkNumber;
        }

    public void setCheckNumber(String checkNumber)
        {
            this.checkNumber = checkNumber;
        }
}

主要代码:

public static void main(String[] args) {
    Session session = null;
    Transaction tx = null;
    try {
        SessionFactory sessionFactory = HibernateUtil.getSessionAnnotationFactory();
        session = sessionFactory.openSession();
        tx = session.beginTransaction();

        Check c1=new Check();
        c1.setAmount(40555.4);
        c1.setBankId("AC11112");
        c1.setCheckNumber("CK12222CD");

        Check c2=new Check();
        c2.setAmount(50555.4);
        c2.setBankId("AC11111");
        c2.setCheckNumber("CK12233EW");

        session.persist(c1);//Insert check object c1
        session.persist(c2);//Insert check object c2

        tx.commit();
        System.out.println("After commit");
    } catch (RuntimeException e) {
        try {
            tx.rollback();
        } catch (RuntimeException rbe) {
            System.err.println("Couldn’t roll back transaction"+ rbe);
       }
        throw e;
    } finally{
        if(session != null){
            session.close();
        }
    }
    System.out.println("Success");
}

hibernate.cfg.xml 文件:确保 hibernate.dialect 是 org.hibernate.dialect.PostgreSQLDialect

<hibernate-configuration>
<session-factory>
    <property name="hibernate.dialect">org.hibernate.dialect.PostgreSQLDialect</property>
    <property name="hibernate.hbm2ddl.auto">update</property>
    <property name="hibernate.connection.driver_class">org.postgresql.Driver</property><!-- com.mysql.jdbc.Driver -->
    <property name="hibernate.connection.url">jdbc:postgresql://localhost:5432/postgres?createDatabaseIfNotExist=true</property> <!-- jdbc:mysql://localhost:5432/postgres?createDatabaseIfNotExist=true -->
    <property name="hibernate.connection.username">postgres</property><!-- postgres -->
    <property name="hibernate.connection.password">postgres</property><!-- postgres -->
    <property name="show_sql">true</property>
    <property name="hibernate.current_session_context_class">thread</property> 
    <mapping class="stack.filter.Check"/>
</session-factory>

输出: