Question

我收到错误消息“列“ systementi0_.Id不存在”。我正在使用PostgreSql和Hibernate。我的实体有代码：

@Entity
@Table(name = "system_table", schema = "blue_schema")
public class SystemEntity {

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    @Column(name = "Id", unique = true)
    private int id;

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

    @Column(name = "sys_description")
    private String systemDescription;

    @Column(name = "tech_description")
    private String technologyDescritpion;

    @Column(name = "owner_name")
    private String owner;

    public SystemEntity() {
        // TODO Auto-generated constructor stub
    }

    public SystemEntity(int id, String name, String systemDescription, String technologyDescritpion, String owner) {
        super();
        this.id = id;
        this.name = name;
        this.systemDescription = systemDescription;
        this.technologyDescritpion = technologyDescritpion;
        this.owner = owner;
    }

    public SystemEntity(String name, String systemDescription, String technologyDescritpion, String owner) {
        super();
        this.name = name;
        this.systemDescription = systemDescription;
        this.technologyDescritpion = technologyDescritpion;
        this.owner = owner;
    }

一开始，我正试图从数据库中获取该表中的所有数据。

    @Override
    public List<SystemEntity> getAllSystems() {

        Session currentSession = sessionFactory.getCurrentSession();

        Query<SystemEntity> theQuery = currentSession.createQuery("from SystemEntity", SystemEntity.class);

        List<SystemEntity> listOfSystems = theQuery.getResultList();

        return listOfSystems;
    }

这是我的数据库类型和输出： Table output

Table types

我的架构名称已在@Table批注中阐明，但仍然出现错误：

SEVERE: Servlet.service() for servlet [dispatcher] in context with path [/ContractManager] threw exception [Request processing failed; nested exception is javax.persistence.PersistenceException: org.hibernate.exception.SQLGrammarException: could not extract ResultSet] with root cause
org.postgresql.util.PSQLException: Error: columnsystementi0_.id does not exist.

我看到了类似我的帖子，但解决方案很简单，只需在@Table中添加架构名称。

Answer 1

这是一个常见的错误。第一条建议：不要在所有数据库实体（架构，表或列）的名称中使用大写字母。您的id列名称为“ ID ”。尝试“ id ”。第二个：我建议您在postresql中使用序列生成器：

@Entity
@Table(name = "system_table", schema = "blue_schema")
@SequenceGenerator(schema = "blue_schema", name = "system_table_seq", allocationSize = 1, sequenceName = "system_table_seq")
public class SystemEntity {

    // other code below 
    // ... 

}

最后一条建议：不要在JPA实体中使用原始类型。尝试：

@Entity
@Table(name = "system_table", schema = "blue_schema")
@SequenceGenerator(schema = "blue_schema", name = "system_table_seq", allocationSize = 1, sequenceName = "system_table_seq")
public class SystemEntity {

    @Id
    @GeneratedValue(generator = "system_table_seq", strategy = GenerationType.SEQUENCE)
    private Integer id;

    // other code below 
    // ... 

}

Answer 2

也许您应该使用Integer数据类型而不是int，并且应该尝试直接使用表名。 system_table

org.postgresql.util.PSQLException：错误：列systementi0_.id不存在-Hibernate，PostgreSql

2 个答案: