第golanggorm的關(guān)系關(guān)聯(lián)實(shí)現(xiàn)示例目錄1.1.屬于1.2.包含一個(gè)1.3.包含多個(gè)1.4.多對(duì)多1.5.多種包含1.6.關(guān)聯(lián)模式1.關(guān)聯(lián)

1.1.屬于

//`User`屬于`Profile`,`ProfileID`為外鍵

typeUserstruct{

gorm.Model

ProfileProfile

ProfileIDint

typeProfilestruct{

gorm.Model

Namestring

db.Model(amp;user).Related(amp;profile)

////SELECT*FROMprofilesWHEREid=111;//111是user的外鍵ProfileID

指定外鍵

typeProfilestruct{

gorm.Model

Namestring

typeUserstruct{

gorm.Model

ProfileProfile`gorm:"ForeignKey:ProfileRefer"`//使用ProfileRefer作為外鍵

ProfileReferint

指定外鍵和關(guān)聯(lián)外鍵

typeProfilestruct{

gorm.Model

Referstring

Namestring

typeUserstruct{

gorm.Model

ProfileProfile`gorm:"ForeignKey:ProfileID;AssociationForeignKey:Refer"`

ProfileIDint

1.2.包含一個(gè)

//User包含一個(gè)CreditCard,UserID為外鍵

typeUserstruct{

gorm.Model

CreditCardCreditCard

typeCreditCardstruct{

gorm.Model

UserIDuint

Numberstring

varcardCreditCard

db.Model(amp;user).Related(amp;card,"CreditCard")

////SELECT*FROMcredit_cardsWHEREuser_id=123;//123isuser'sprimarykey

//CreditCard是user的字段名稱，這意味著獲得user的CreditCard關(guān)系并將其填充到變量

//如果字段名與變量的類型名相同，如上例所示，可以省略，如：

db.Model(amp;user).Related(amp;card)

指定外鍵

typeProfilestruct{

gorm.Model

Namestring

UserReferuint

typeUserstruct{

gorm.Model

ProfileProfile`gorm:"ForeignKey:UserRefer"`

指定外鍵和關(guān)聯(lián)外鍵

typeProfilestruct{

gorm.Model

Namestring

UserIDuint

typeUserstruct{

gorm.Model

Referstring

ProfileProfile`gorm:"ForeignKey:UserID;AssociationForeignKey:Refer"`

1.3.包含多個(gè)

//User包含多個(gè)emails,UserID為外鍵

typeUserstruct{

gorm.Model

Emails[]Email

typeEmailstruct{

gorm.Model

Emailstring

UserIDuint

db.Model(amp;user).Related(amp;emails)

////SELECT*FROMemailsWHEREuser_id=111;//111是user的主鍵

指定外鍵

typeProfilestruct{

gorm.Model

Namestring

UserReferuint

typeUserstruct{

gorm.Model

Profiles[]Profile`gorm:"ForeignKey:UserRefer"`

指定外鍵和關(guān)聯(lián)外鍵

typeProfilestruct{

gorm.Model

Namestring

UserIDuint

typeUserstruct{

gorm.Model

Referstring

Profiles[]Profile`gorm:"ForeignKey:UserID;AssociationForeignKey:Refer"`

1.4.多對(duì)多

//User包含并屬于多個(gè)languages,使用`user_languages`表連接

typeUserstruct{

gorm.Model

Languages[]Language`gorm:"many2many:user_languages;"`

typeLanguagestruct{

gorm.Model

Namestring

db.Model(amp;user).Related(amp;languages,"Languages")

////SELECT*FROM"languages"INNERJOIN"user_languages"ON"user_languages"."language_id"="languages"."id"WHERE"user_languages"."user_id"=111

指定外鍵和關(guān)聯(lián)外鍵

typeCustomizePersonstruct{

IdPersonstring`gorm:"primary_key:true"`

Accounts[]CustomizeAccount`gorm:"many2many:PersonAccount;ForeignKey:IdPerson;AssociationForeignKey:IdAccount"`

typeCustomizeAccountstruct{

IdAccountstring`gorm:"primary_key:true"`

Namestring

譯者注：這里設(shè)置好像缺失一部分

1.5.多種包含

支持多種的包含一個(gè)和包含多個(gè)的關(guān)聯(lián)

typeCatstruct{

Idint

Namestring

ToyToy`gorm:"polymorphic:Owner;"`

typeDogstruct{

Idint

Namestring

ToyToy`gorm:"polymorphic:Owner;"`

typeToystruct{

Idint

Namestring

OwnerIdint

OwnerTypestring

注意：多態(tài)屬性和多對(duì)多顯式不支持，并且會(huì)拋出錯(cuò)誤。

1.6.關(guān)聯(lián)模式

關(guān)聯(lián)模式包含一些幫助方法來處理關(guān)系事情很容易。

//開始關(guān)聯(lián)模式

varuserUser

db.