从Go中的postgres获取错误代码号

Question

I'm simply unable to retrieve the error code number when I get an error in postgres.

In the test of my program I know I'll get the following error " pq: duplicate key value violates unique constraint "associations_pkey"".

Looking in the postgres docs this is most likely an pq error code of 23505.

I need to get that number in my Go program so that I can check on different types of errors and respond to the end user in a helpful way.

However, I can't seem to get hold of the error code in Go, only the error message. My code is as follows:

stmt, _ := DB.Prepare("INSERT INTO table (column_1) VALUES ($1)")

_, err = stmt.Exec("12324354")

if err != nil {
    log.Println("Failed to stmt .Exec while trying to insert new association")
    log.Println(err.Error())
    fmt.Println(err.Code())

} else {
    Render.JSON(w, 200, "New row was created succesfully")
}

Answer 1

You need to type assert the error to the type *pq.Error:

pqErr := err.(*pq.Error)
log.Println(pqErr.Code)