Golang database/sql.Rows.Next function examples

package database/sql

Next prepares the next result row for reading with the Scan method. It returns true on success, or false if there is no next result row or an error happened while preparing it. Err should be consulted to distinguish between the two cases.

Every call to Scan, even the first one, must be preceded by a call to Next.

Golang database/sql.Rows.Next function usage examples

Example 1:

 rows, err := db.Query("INSERT INTO distributors (did, dname) VALUES (DEFAULT, 'XYZ Widgets') RETURNING did;")
 if err != nil {
  t.Fatal(err)
 }
 if !rows.Next() { // <----- here
  t.Fatal("no rows")
 }

Example 2:

 rows, err := db.conn.Query("SELECT name, parent_id FROM edge WHERE entity_id = ?;", id)
 if err != nil {
 return refs
 }

 defer rows.Close()

 for rows.Next() { // <--- here
 var name string
 var parentId string
 if err := rows.Scan(&name, &parentId); err != nil {
 return refs
 }
 refs = append(refs, &Edge{
 EntityID: id,
 Name: name,
 ParentID: parentId,
  })
 }

References :

https://github.com/docker/docker/blob/master/pkg/graphdb/graphdb.go

http://golang.org/pkg/database/sql/#Rows.Next