Spring Data 似乎不理解@Column 名称

问题描述

我正在使用 Spring-boot 1.4.1.RELEASE，通过 Spring Data 和 Hibernate 将一些数据保存到 MySQL 数据库中.

I'm using Spring-boot 1.4.1.RELEASE, with Spring Data and Hibernate to persist some data into a MySQL database.

我有这个类，Respondent，用 @Entity 注释，其中一个字段注释如下:

I have this class, Respondent, annotated with @Entity and one of the fields annotated as below:

@Column(name = "firstName", nullable = false, length = 100)
private String firstName;

当我尝试通过在其 CrudRepository 上调用 save() 将响应者保存到数据库时，我收到此错误:

When I try to save a Respondent to the DB by calling save() on its CrudRepository<Respondent, Long>, I get this error:

ERRORcom.mysql.jdbc.exceptions.jdbc4.MySQLSyntaxErrorException: Unknown column 'first_name' in 'field list'

这个错误在我为字段添加 @Column 注释之前就开始发生了，所以我认为将 firstName 映射到 first_name 是一些默认的 Hibernate 行为，但我已经添加了 @Column 注释，没有任何改变.还是错了?我已经用 mvn clean package 重建了应用程序.

This error had started occurring before I had the @Column annotation for the field, so I thought it was some default Hibernate behaviour to map firstName to first_name, but I've added the @Column annotation to it and nothing changed. Is it still wrong? I've already rebuilt the application with mvn clean package.

这是我的受访者实体:

@Entity
public class Respondent {

    @Id
    @GeneratedValue(strategy=GenerationType.AUTO)
    private Long id;
    @Column(name = "firstName", nullable = false, length = 100)
    private String firstName;
    private String tussenvoegsel;
    @Column(name = "lastName", nullable = false, length = 100)
    private String lastName;

    @ManyToOne(fetch = FetchType.LAZY)
    @JoinColumn(name = "Company_id", nullable = false)
    private Company company;

推荐答案

默认情况下，Spring 使用 jpa.SpringNamingStrategy 来生成表名.

By default Spring uses jpa.SpringNamingStrategy to generate the table names.

ImprovedNamingStrategy 会将 CamelCase 转换为 SNAKE_CASE，而 EJB3NamingStrategy 只是使用未更改的表名.

The ImprovedNamingStrategy will convert CamelCase to SNAKE_CASE where as the EJB3NamingStrategy just uses the table name unchanged.

您可以尝试将 naming_strategy 更改为:

You can try to change the naming_strategy to:

spring.jpa.hibernate.naming_strategy=org.hibernate.cfg.EJB3NamingStrategy

或 @Column name 属性应该是小写的 @Column(name = "firstname")

or the @Column name attribute should be in lowercase @Column(name = "firstname")

对于 Hibernate 5 这应该可以工作(我不太确定你是否还需要上面的一个.但是两个都试试):

For Hibernate 5 this should work (I am not quite sure if you also need the above one. But try it with both):

spring.jpa.hibernate.naming.implicit-strategy=org.hibernate.boot.model.naming.ImplicitNamingStrategyLegacyJpaImpl
spring.jpa.hibernate.naming.physical-strategy=org.hibernate.boot.model.naming.PhysicalNamingStrategyStandardImpl

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