func (db *DB) rawSelectByStruct(structType reflect.Type, qi SqlQueryInfo) (rows *sql.Rows, fields []string, err error) {
// nums of struct's fields
lf := structType.NumField()
// type's fields
fields = make([]string, 0, lf)
// sql select columns, it's Snake Cased
columns := make([]string, 0, lf)
// get fields in structType,
// and convert to sql query column name
for i := 0; i < lf; i++ {
structField := structType.Field(i)
fieldName := structField.Name
fields = append(fields, fieldName)
columns = append(columns, utils.SnakeCasedName(fieldName))
}
// tableName := utils.SnakeCasedName(utils.StructName(s))
tableName := utils.SnakeCasedName(structType.Name())
// TODO: check the fileds has specified ?
qi.Fields = strings.Join(columns, ", ")
// run query from db
rows, err = db.Select(tableName, qi)
return
}
// insert struct to database
// if i is pointer to struct and has a int type field named "Id"
// the field "Id" will set to the last insert id if has LastInsertId
//
// field mapping rule is: HelloWorld => hello_world
// mean that struct's field "HelloWorld" in database table's field is "hello_world"
// table name mapping use the same rule as field
func (db *DB) InsertStruct(i interface{}) (sql.Result, error) {
m := utils.StructToSnakeKeyMap(i)
table := utils.SnakeCasedName(utils.StructName(i))
r, err := db.Insert(table, m)
if err == nil {
insertId, err2 := r.LastInsertId()
if err2 == nil && insertId > 0 {
ps := reflect.ValueOf(i)
if ps.Kind() == reflect.Ptr {
// struct
s := ps.Elem()
if s.Kind() == reflect.Struct {
// exported field
f := s.FieldByName("Id")
if f.IsValid() {
// A Value can be changed only if it is
// addressable and was not obtained by
// the use of unexported struct fields.
if f.CanSet() {
// change value of N
if f.Kind() == reflect.Int {
if !f.OverflowInt(insertId) {
f.SetInt(insertId)
}
}
}
}
}
}
}
}
return r, err
}