Bulk insert rows from an array to an sql server with golang - mysql

Question

I have a list of structs as follows
row = [
{
"name":<name1>,
"age" :<age1>,
"job" :<job1>
},
{
"name":<name1>,
"age" :<age1>,
"job" :<job1>
},
{
"name":<name1>,
"age" :<age1>,
"job" :<job1>
},
etc...
]
I want to insert this into an SQL table. So far I was running a loop through the array and inserting each row one by one. But is there any other way by which I can insert all the rows with just one query? I know bulk insert, but my understanding is that, for bulk insert, I will have to import data from an external file. I don't want to do that. How do I use the data from this array and perform bulk insert?

Answer 1

type Person struct {
Name string
Age int
Job string
}
func InsertPeople(db *sql.DB, personSlice []*Person) error {
var queryString = `INSERT INTO "person_table" (
"name"
, "age"
, "job"
) VALUES `
numOfFields := 3
params := make([]interface{}, len(personSlice)*numOfFields)
for i, p := range personSlice {
pos := i * numOfFields
params[pos+0] = p.Name
params[pos+1] = p.Age
params[pos+2] = p.Job
queryString += `(?, ?, ?),`
}
queryString = queryString[:len(queryString)-1] // drop last comma
_, err := db.Exec(queryString, params...)
return err
}

Answer 2

You aren't going to be able to do any kind of super-optimized bulk insert without placing a file on the server I don't think.
I am not sure if the db library supports it but using the SQLX extension you can build a single insert statement with named bindvars that go against a struct. You can then pass an array of these structs to a method like NamedExec.
Something like this:
users := []User{
{
Name: "alex",
Email: "alex#example.com",
},
{
Name: "muhammed",
Email: "muhammed#example.com",
},
}
db.NamedExec("insert into users (NAME, EMAIL) values (:Name, :Email);", users)