HasOne和HasMany具有相同的域類和級聯保存

Question

我有2個域類;其中最糟糕的部分代表了一個電子郵件地址，包含用戶名和電子郵件地址本身。其他類表示一封電子郵件，與主題，發件人（一個電子郵件地址）和收件人（電子郵件地址列表）：

class EmailMessage { 
    static hasMany = [ to: EmailAddress ] 
    EmailAddress from 
    String subject 
} 

class EmailAddress { 
    String name 
    String address 
} 

但正如我希望這個代碼不工作：

EmailMessage msg = new EmailMessage() 
msg.from = new EmailAddress(name: "User 1", address: "user1@domain.com") 
[new EmailAddress(name: "User 2", address: "user2@domain.com"), new EmailAddress(name: "User 3", address: "user3@domain.com")].each { 
    msg.addToTo(it) 
} 
msg.subject = "Asunto" 
msg.save(failOnError: true) 

我得到這個錯誤：

| Error 2013-08-14 21:08:40,362 [localhost-startStop-1] ERROR util.JDBCExceptionReporter - La columna "FROM_ID" no permite valores nulos (NULL) 
NULL not allowed for column "FROM_ID"; SQL statement: insert into email_message (id, version, from_id, subject) values (null, ?, ?, ?) [23502-164] 
| Error 2013-08-14 21:08:40,375 [localhost-startStop-1] ERROR context.GrailsContextLoader - Error initializing the application: could not insert: [prueba.EmailMessage]; 
SQL [insert into email_message (id, version, from_id, subject) values (null, ?, ?, ?)]; constraint [null]; nested exception is org.hibernate.exception.ConstraintViolationException: could not insert: [prueba.EmailMessage] 
Message: could not insert: [prueba.EmailMessage]; SQL [insert into email_message (id, version, from_id, subject) values (null, ?, ?, ?)]; constraint [null]; 
nested exception is org.hibernate.exception.ConstraintViolationException: could not insert: [prueba.EmailMessage] 

我不知道這甚至可以做到，或者級聯保存爲我想不工作。

我thik我嘗試過hasMany，belongsTo等每個類的所有組合，沒有成功。

我也讀過這個主題，但它沒有按預期工作Grails hasOne and hasMany same domain。

任何人都可以幫助我嗎？提前感謝和感謝。

Answer 1

這個工作對我來說在標準內存數據庫

class EmailMessage { 
    static hasMany = [ to: EmailAddress ] 
    EmailAddress from 
    String subject 

    static mapping = { 
     from cascade: "save-update" //Pretty sure this is unnecessary 
    } 
} 

class EmailAddress { 
    String name 
    String address 

    static belongsTo = EmailMessage 
} 

Answer 2

不幸的是，在保存父項之前，您必須先保存您的from。

EmailMessage msg = new EmailMessage() 
msg.from = new EmailAddress(name: "User 1", address: "user1@domain.com") 
if (!msg.from.save(flush: true)) { 
    log.error("message could not be saved: " + msg.from.errors) 
} 
[new EmailAddress(name: "User 2", address: "user2@domain.com"), new EmailAddress(name: "User 3", address: "user3@domain.com")].each { 
    msg.addToTo(it) 
} 
msg.subject = "Asunto" 
msg.save(failOnError: true) 

1：1關係中沒有層疊保存。