Question

我正在尝试学习Grails，我遇到了一个奇怪的问题。我创建了一个应用程序，并将PostgreSQL设置为我的数据库。这是我的application.yml

dataSource:
    pooled: true
    jmxExport: true
    driverClassName: org.postgresql.Driver
    username: postgres
    password: XxXxXxXxX

environments:
    development:
        dataSource:
            dbCreate: update
            url: jdbc:postgresql://localhost:5432/datarh
    test:
        dataSource:
            dbCreate: update
            url: jdbc:postgresql://localhost:5432/datarh
    production:
        dataSource:
            dbCreate: update
            url: jdbc:postgresql://localhost:5432/datarh
            properties: <ommited>

然后，我创建了两个域类：

class Candidate {

    String name
    String linkedin
    String email
    String phone
    String personalMessage
    String pathCV
    static hasMany = [skills: Skill]

    static constraints = {

    }
}

class Skill {

    String skill
    String description

    static hasMany = [candidates: Candidate]
    static belongsTo = Candidate

    static constraints = {

    }
}

好的，现在我开始申请了，我去检查我创建的表格。令我惊讶的是，我得到了这个：

CREATE TABLE candidate
(
  id bigint NOT NULL,
  version bigint NOT NULL,
  email character varying(255) NOT NULL,
  linkedin character varying(255) NOT NULL,
  name character varying(255) NOT NULL,
  pathcv character varying(255) NOT NULL,
  personal_message character varying(255) NOT NULL,
  phone character varying(255) NOT NULL,
  CONSTRAINT candidate_pkey PRIMARY KEY (id)
)
WITH (
  OIDS=FALSE
);
ALTER TABLE candidate
  OWNER TO postgres;

CREATE TABLE candidate_skills
(
  candidate_id bigint NOT NULL,
  skill_id bigint NOT NULL,
  CONSTRAINT candidate_skills_pkey PRIMARY KEY (candidate_id, skill_id),
  CONSTRAINT fk_941r0fvlnkcvq9r7jqn5awce4 FOREIGN KEY (candidate_id)
      REFERENCES candidate (id) MATCH SIMPLE
      ON UPDATE NO ACTION ON DELETE NO ACTION,
  CONSTRAINT fk_t537lxgp89abb42uf1robp1xp FOREIGN KEY (skill_id)
      REFERENCES skill (id) MATCH SIMPLE
      ON UPDATE NO ACTION ON DELETE NO ACTION
)
WITH (
  OIDS=FALSE
);
ALTER TABLE candidate_skills
  OWNER TO postgres;

CREATE TABLE skill
(
  id bigint NOT NULL,
  version bigint NOT NULL,
  description character varying(255) NOT NULL,
  skill character varying(255) NOT NULL,
  CONSTRAINT skill_pkey PRIMARY KEY (id)
)
WITH (
  OIDS=FALSE
);
ALTER TABLE skill
  OWNER TO postgres;

如您所见，所有表都是使用NOT-NULL创建的。我该如何解决这个问题？

我的环境：

PostgresSQL 9.4
Grails版本：3.1.4
Groovy版本：2.4.6
JVM版本：1.8.0_77

Answer 1

您的持久属性默认为不可为空。如果您希望它们可以为空，那么您可以明确指出：

class Skill {

    String skill
    String description

    static hasMany = [candidates: Candidate]
    static belongsTo = Candidate

    static constraints = {
        description nullable: true
        skill nullable: true

        // ...

    }
}

为什么Grails默认生成非空列？

1 个答案: