0

我是 Grails 和 GORM 的新手，但我在遗留 PostgreSQL 上有一个旧的 JPA2 (Hibernate) 应用程序要映射，但我无法让抽象类的继承工作，这是问题的一个例子，让我们使用这个表：

users (id serial, username varchar, password char(44), user_modified integer, last_modified timestamp);
roles (id serial, role varchar, description varchar, enabled boolean, user_modified integer, last_modified timestamp);
permissions (user_id integer, role_id integer, enabled boolean);

如您所见，这些表使用数字自动递增 id，但并非所有表都如此，在旧的 JPA 映射中，我使用 a@MappedSuperclass来映射 ID 配置，例如 id 生成器和一些审计列：

@MappedSuperclass
public abstract class DefId {
    @Id 
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    protected Long id;

    @NotNull 
    @Column(name = "user_modified")
    protected Long userModified;

    @Version 
    @Column(name = "last_modified") 
    @Source(SourceType.DB)
    protected Date lastModified;

    //getters and setters
}

这是我迄今为止在grails中尝试过的：

DefId.groovy：

abstract class DefId {
    /*In the actual source this are protected fields
    with public getters/setters removed for less code*/
    Long id; 
    Long userModified;
    Timestamp version;

    static mapping = {
        id generator: 'identity'
        version 'last_modified'
        userModified column: 'user_modified'
    }
}

用户.groovy：

package maptest.domain

import maptest.model.DefId

class User extends DefId {
    String username
    String password
    boolean enabled
    static hasMany = [roles: Role];

    static mapping = {
        table name: "users", schema: "core"
        roles joinTable: [name: "permissions", key: "user_id"]
    }

    static constraints = {
        username blank: false, size: 2..20, matches: "^[A-Za-z]\\w+\$", unique: true
        password blank: false, matches: "^(?:[A-Za-z0-9+/]{4})*(?:[A-Za-z0-9+/]{2}==|[A-Za-z0-9+/]{3}=)?\$"
        preferences unique: true
    }
}

角色.groovy

package maptest.domain

import maptest.domain.DefId

class Role extends DefId{
    String role
    String description
    boolean enabled

    static hasMany = [users: User];
    static belongsTo = [User];

    static mapping = {
        table name: "roles", schema: "core"
        users joinTable: [name: "permissions", key: "role_id"]
    }
    static constraints = {
        role blank: false, size: 2..20, matches: "^[A-Za-z]\\w+\$", unique: true
        description   size: 2..50
    }
}

如果我将抽象类留在域结构中，我会遇到异常：org.springframework.jdbc.BadSqlGrammarException: Hibernate operation: ERROR: relation "def_id" don't exists;这是真的，但我并不想保留抽象类。

如果我更改包并将抽象类移动到 src/groovy 那么我得到：org.springframework.orm.hibernate4.HibernateSystemException: Unknown entity: mapetest.domain.User;

我还尝试将grails.gorm.default.mapping = { id generator: 'identity' }添加到 Config.groovy 并从超类中删除 id 字段，但这只会给我带来另一个错误：Error loading plugin manager: Identity property not found, but required in domain class [maptest.domain.Role]

有人知道吗？将id generator: 'identity' ' 添加到每个域类中，解决了它，但这违背了继承的目的。

对不起，我的英语是第二语言

4

1 回答 1

1

Put your abstract class in the domain classes folder. You also need to tell Grails to consider a different table per class:

static mapping = {
  tablePerSubclass true
}

The default is only one table with a class column.

You also don't need to declare the id field, since it's auto generated by Grails, with the Long type.

于 2013-10-26T18:35:00.917 回答