xorm/session_pluck.go

62 lines
1.7 KiB
Go

package xorm
import (
"errors"
"fmt"
"reflect"
"strings"
)
// Pluck retrieve a list of column values.
// colName is the column name where values from
// slicePtr should be a slice which will filled by the list values
// beans is optional which represents the table, should be a *Struct
func (session *Session) Pluck(colName string, slicePtr interface{}, beans ...interface{}) error {
if session.isAutoClose {
defer session.Close()
}
return session.pluck(colName, slicePtr, beans...)
}
func (session *Session) pluck(colName string, slicePtr interface{}, beans ...interface{}) error {
sliceValue := reflect.Indirect(reflect.ValueOf(slicePtr))
if sliceValue.Kind() != reflect.Slice {
return errors.New("needs a pointer to a slice")
}
sliceElemType := sliceValue.Type().Elem()
rows := []map[string]interface{}{}
query := session
if session.statement.selectStr == "" {
query.Select(colName)
}
if len(beans) != 0 {
// find table
bean := beans[0]
beanValue := reflect.ValueOf(bean)
if beanValue.Kind() != reflect.Ptr || beanValue.Elem().Kind() != reflect.Struct {
return errors.New("needs a pointer to a struct")
}
session.statement.setRefValue(beanValue)
tbName := session.statement.TableName()
query.Table(tbName)
}
if err := query.Find(&rows); err != nil {
return err
}
colSegs := strings.Split(colName, ".")
col := colSegs[len(colSegs)-1] // last one
col = strings.Trim(col, "`") // unwrap column name
nSlice := reflect.New(sliceValue.Type()).Elem()
rowsLen := len(rows)
for i := 0; i < rowsLen; i++ {
if v, ok := rows[i][col]; !ok {
return fmt.Errorf("cannot find column: %s", col)
} else {
nSlice = reflect.Append(nSlice, reflect.ValueOf(v).Convert(sliceElemType))
}
}
sliceValue.Set(nSlice)
return nil
}