出錯創建對象

Question

你好，我有這兩類

class Company { 
    String company_name 
    static constraints = { 
     company_name size: 3..20, unique: true, nullable: false 
    } 
    String toString() { return company_name} 
} 

class Job {  
    String job_name 
    Company company 

    static constraints = { 
     job_name size: 3..20, unique: false, nullable: false 
     company nullable: false 
    } 
    String toString() { return job_name} 
} 

而且這種方法：

def register(String company_name,String job_name) 
{ 
    def job = new Job(company : new Company(company_name : company_name), job_name: job_name) 
    if (job.validate() && job.save()) 
    { 
     redirect(url:"https//localhost:8080") 
    } 
} 

我可以例如Company:nvidia，Job:worker創建對象，但如果我試圖創建的另一個位置公司nvidia- Company:nvidia,Job:owner我得到一個錯誤，爲什麼呢？它是在if條款

Answer 1

你有一個unique約束在company_name屬性和您的代碼試圖創建一個新的Company實例與每個新的Job實例。

你應該做的是這樣的：

def nvidiaCompany = new Company(company_name: 'nVidia').save() 

def jobDesigner = new Job(company: nvidiaCompany, job_name: 'designer') 
def jobDeveloper = new Job(company: nvidiaCompany, job_name: 'developer') 

所以你重用Company實例。如果你在代碼中只創建一個Job情況下，你必須首先獲得Company實例：

def nvidiaCompany = Company.findByCompanyName('nvidia') 
def jobDesigner = new Job(company: nvidiaCompany, job_name: 'designer')