在 golang 中使用 map[string]interface{} 輸入為 postgresql 創建動態查詢

Question

我有 map[string]interface 輸入用戶，如下所示

user := map[string]interface{}{
       "firstname": firstname,
       "lastname":  lastname,
       "country":   country,
       "email":     email,
   }

上面給出的值來自其他函數作為變量，因此未在“”中表示。

比如我需要從上面的界面生成如下動態查詢： "INSERT INTO USERTABLE (key1, key2, key3, key4) VALUES ($1, $2, $3, $4) RETURNING userid", val1, val2, val3, val4)

迭代器將計算鍵和值並生成如下查詢

"INSERT INTO USERTABLE (firstname, lastname, country, email) VALUES ($1, $2, $3, $4) RETURNING userid", firstname, lastname, country, email)

希望建立一個動態字符串。

Answer 1

純Go

func prepareInsert(table string, params map[string]interface{}) string {
    columns := len(params)
    fieldSlice := make([]string, 0, columns)
    for field, _ := range params {
        fieldSlice = append(fieldSlice, field)
    }
    fields := strings.Join(fieldSlice, ",")

    placeholders := prepareQueryPlaceholders(1, columns)
    return fmt.Sprintf(`INSERT INTO %s (%s) VALUES (%s) RETURNING %s`, table, fields, placeholders, fields)
}

func prepareQueryPlaceholders(start, quantity int) string {
    placeholders := make([]string, 0, quantity)
    end := start + quantity
    for i := start; i < end; i++ {
        placeholders = append(placeholders, strings.Join([]string{"$", strconv.Itoa(i)}, ""))
    }
    return strings.Join(placeholders, ",")
}

操場