Iteration doesn't support parsing raw data into struct?

[Mattieuga]

I may be missing something, but the docs aren't really clear on this. They mention the Rows() function can be used to iterate over table but since this returns *sql.Row, I'm not sure how to scan this into the struct for this row. The great thing about gorm is that it handles parsing the sql data into a struct, but this seems to be missing for iteration.

The example shows this, which really isn't great given how easy all of the other functions are to use.

rows.Scan(&name, &age, &email)

[jinzhu]

Hi @Mattieuga

Yes, we don't have this function now. ;(

The Rows method is build for those users who don't like gorm's syntax, but only would like to use gorm as a query builder.

But if gorm will support this feature, do you have any suggestions for the API naming?

[Mattieuga]

Something with a similar API to Rows but that takes care of scanning the data would be great. Something like this would match the style of the rest of Gorm pretty well:

user := User{}

iter, err := db.Where("role = ?", "admin").Or("role = ?", "super_admin").Iter()

for iter.Next(&user) {
  ...
}

Error handling can be tricky with the Close() that has to be deferred. I like the way labix handles this in the mgo package. You can keep the nice for loop and you basically do if err := iter.Close(); err != nil {...} after the for loop to check if an error happened during the iteration.

[colegleason]

@jinzhu I actually would like to see this support not because I dislike the syntax of Gorm but because I don't want to load every object into memory at once. If I have a table with a large number of rows I use the iterator to process them.

Iterating with the Rows is less that ideals since I can't Scan with a struct. Would it be possible to either add Iter support as @Mattieuga suggested or exposing the function that unmarshals Rows into Structs?

[jinzhu]

Usage

rows, err := db.Model(&User{}).Where("name = ?", "jinzhu").Select("name, age, email").Rows() // (*sql.Rows, error)
defer rows.Close()

for rows.Next() {
  var user User
  db.ScanRows(rows, &user)
  // do something
}