数组Varchar（psql）到数组字符串（golang）

Question

I would like to know how i can get my array varchar in my psql database in array string in go for render it in json.

I actually do that

In creation of my table i create my column like that :

tags varchar(50)[] default NULL

when i use my select request for get it in golang :

var rowtags []uint8
err = rows.Scan(&rowtags)
if err != nil {
    log.Fatal(err)
}

i have try to make a fonction that transform uint8[] to string[]

func Uint8toString(array []uint8) []string {

    var ret = make([]string, len(array))
    for i := 0; i < len(array); i++{
        ret[i] = string(array[i])
    }
    return (ret)
}

so i apply function of my var rowstag

var tags := Uint8toString(rowtags)

and when i render struct where var tags is, I get that

  "Tags": [
    "{",
    "#",
    "c",
    ",",
    "#",
    "c",
    ",",
    "#",
    "c",
    "o",
    "u",
    "c",
    "o",
    "u",
    ",",
    "#",
    "c",
    "d",
    "}"
  ],

of course I would like it

  "Tags": [
    "#c",
    "#c",
    "#coucou",
    "#cd"
  ],

thank's for helping me , I'm on golang a short time , and I find no solution.

Answer 1

First of all, why do you have an column called tags that contains multiple tag values? Wouldn't it be better to have another table with a foreign key to the one that tags column is currently in so that each tag value is it's own row? If you have that, you should be able to do something really easy like:

rows := db.QueryRow("SELECT tag from tags_table where foreign_key = 123")
var asSlice []string
err := row.Scan(&asSlice) 

If you have to put it all inside of one column, would it be possible to just store it as JSON? Then you could use the "encoding/json" package do something simple like:

func Uint8toString(array []uint8) []string {
     var stringArray []string
     json.Unmarshal(array, &stringArray)
     return stringArray
}

Although I think you should rethink the way you are implementing the above tags column, you could also use the following logic to parse it into strings but it assumes that the format will always be similar to what you've posted:

func Uint8toString(array []uint8) []string {
    stringNoBrackets := string(array[1:len(array)-1])
    return strings.Split(stringNoBrackets,",")
}