Golang database/sql.Rows.Scan function examples

package database/sql

Scan copies the columns in the current row into the values pointed at by dest.

If an argument has type *[]byte, Scan saves in that argument a copy of the corresponding data. The copy is owned by the caller and can be modified and held indefinitely. The copy can be avoided by using an argument of type *RawBytes instead; see the documentation for RawBytes for restrictions on its use.

If an argument has type *interface{}, Scan copies the value provided by the underlying driver without conversion. If the value is of type []byte, a copy is made and the caller owns the result.

Golang database/sql.Rows.Scan function usage examples

Example 1:

 var out bool
 rows = dbt.mustQuery("SELECT value FROM test")
 if rows.Next() {
 rows.Scan(&out)  //<-- here
 if true != out {
 dbt.Errorf("true != %t", out)
 }
 if rows.Next() {
 dbt.Error("unexpected data")
 }
 } else {
 dbt.Error("no data")
 }

Example 2:

 var target interface{}

 if rows.Next() {
 err := rows.Scan(target)
 return err
 }

Example 3:

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

 defer rows.Close()

 for rows.Next() {
 var entityId, entityName string
 if err := rows.Scan(&entityId, &entityName); err != nil { // <--- here
 return nil, err
 }
 ...

References :

https://github.com/go-sql-driver/mysql/blob/master/driver_test.go

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