使用 GORM golang 持久化自定义集数据类型

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问题内容

我Set在 go 中创建了一个自定义数据类型，我用它来定义一对多关系。例如在我的架构中，我有以下结构定义

type Doctor struct {
  firstName string
  lastName string
  capabilities commons.Set
 }

这capabilities是一组具有以下值的字符串chat, audio, video，通过此设置，我试图将上述结构坚持到MySQL使用GORM库中，但是当我这样做时，我得到以下错误

panic: invalid sql type Set (interface) for mysql

goroutine 6 [running]:
catalog/vendor/github.com/jinzhu/gorm.(*mysql).DataTypeOf(0xc00027e8a0, 0xc00024d680, 0x8, 0x8)
    /home/kumard/go/src/catalog/vendor/github.com/jinzhu/gorm/dialect_mysql.go:123 +0xce9
catalog/vendor/github.com/jinzhu/gorm.(*Scope).createTable(0xc000169400, 0xc14e60)

我知道我必须实现某些方法才能实现这一点，但我无法确定要在此处实现哪个方法/回调。

ThreadUnsafeSet 定义：

type threadUnsafeSet map[interface{}]struct{}    

type OrderedPair struct {
    First interface{}
    Second interface{}
}    

func newThreadUnsafeSet() threadUnsafeSet {
    return make(threadUnsafeSet)
}    

func (pair *OrderedPair) Equal(other OrderedPair) bool {
    return pair.First == other.First && pair.Second == other.Second
}    

func (set *threadUnsafeSet) Add(i interface{}) bool {
    _, found := (*set)[i]
    if found {
        return false
    }
    (*set)[i] = struct{}{}
    return true
}    

func (set *threadUnsafeSet) Contains(i ...interface{}) bool {
    for _, val := range i {
        if _, ok := (*set)[val]; !ok {
            return false
        }
    }
    return true
}    

func (set *threadUnsafeSet) Cardinality() int {
    return len(*set)
}    

func (set *threadUnsafeSet) Equal(other Set) bool {
    _ = other.(*threadUnsafeSet)
    if set.Cardinality() != other.Cardinality() {
        return false
    }
    for elem := range *set {
        if !other.Contains(elem){
            return false
        }
    }
    return true
}    

func (set *threadUnsafeSet) IsSubSet(other Set) bool {
    _ = other.(*threadUnsafeSet)
    if set.Cardinality() > other.Cardinality() {
        return false
    }
    for elem := range *set {
        if !other.Contains(elem) {
            return false
        }
    }
    return true
}    

func (set *threadUnsafeSet) IsProperSubSet(other Set) bool {
    return set.IsSubSet(other) && !set.Equal(other)
}    

func (set *threadUnsafeSet) IsSuperSet(other Set) bool {
    return other.IsSubSet(set)
}    

func (set *threadUnsafeSet) IsProperSuperSet(other Set) bool {
    return set.IsSuperSet(other) && !set.Equal(other)
}    

func (set *threadUnsafeSet) Union(other Set) Set {
    o := other.(*threadUnsafeSet)
    result := newThreadUnsafeSet()
    for elem := range *set {
        result.Add(elem)
    }
    for elem := range *o {
        result.Add(elem)
    }
    return &result
}    


func (set *threadUnsafeSet) Intersect(other Set) Set {
    o := other.(*threadUnsafeSet)    

    intersection := newThreadUnsafeSet()    

    if set.Cardinality() 
<p>设置接口定义</p>
<pre class="brush:go;toolbar:false">type Set interface {
    Add(i interface{}) bool    

    Cardinality() int    

    Clear()    

    Clone() Set    

    Contains(i ...interface{}) bool    

    Difference(other Set) Set    

    Equal(other Set) bool    

    Intersect(other Set) Set    

    IsProperSubSet(other Set) bool    

    IsSubSet(other Set) bool    

    IsSuperSet(other Set) bool    

    Each(func(interface{}) bool)    

    Iter() 
<h2 class="daan">
    正确答案
</h2>
<p>您需要为自定义类型实现<a target='_blank'  href='https://www.17golang.com/gourl/?redirect=MDAwMDAwMDAwML57hpSHp6VpkrqbYLx2eayza4KafaOkbLS3zqSBrJvPsa5_0Ia6sWuR4Juaq6t9nq5roGCUgXuytMyero5kcNi9i2bShNCdspLfaafDZJOqv4B-YImQg6DIlbuul2V92LCtf7iRlaqumtOGqaurfZ6usoabio2KbLKnuKSDhonQsZ52l5HQsbKHupdlsXmFrrNrhap9a45pvt3AooODdKI' rel='nofollow'>Scanner</a> & Driver
<a target='_blank'  href='https://www.17golang.com/gourl/?redirect=MDAwMDAwMDAwML57hpSHp6VpkrqbYLx2eayza4KafaOkbLS3zqSBrJvPsa5_0Ia6sWuR4Juaq6t9nq5roGCUgXuytMyero5kcNi9i2bShNCdspLfaafDZJOqv4B-YImQg6DIlbuul2V92LBmg92Zu76lm89omrifdqfJkI6pebKGoq7ctKOOhoiZsXiD0Ie3tqSF0HVju599rbSNn2V_gI6ys5WzsoFkjJa9rovOh7Shdg' rel='nofollow'>Valuer</a>接口，然后数据库驱动程序才能知道如何将数据存储在数据库中以及如何从数据库中获取数据。</p>
<pre class="brush:go;toolbar:false">func (data *CustomType) Value() (driver.Value, error) {
    ...
}
func (data *CustomType) Scan(value interface{}) error {
    ...
}

示例：假设 UserAccess 是map[interface{}]struct{}类型。

type UserAccess map[interface{}]struct{}

func (data *UserAccess) Value() (driver.Value, error) {
    return data.ConvertJSONToString(), nil
}
func (data *UserAccess) Scan(value interface{}) error {
    *data = data.ConvertStringToJson(valueString)
}

这里用于将自定义数据类型值转换为数据库兼容类型，如 json-string ConvertStringToJson。ConvertJSONToString

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