diff --git a/config/config.go b/config/config.go
index 92508f1..bc9ebf5 100644
--- a/config/config.go
+++ b/config/config.go
@@ -220,6 +220,23 @@ func NewMapping(filename string) (*Mapping, error) {
 	return &mapping, nil
 }
 
+func Bool(val string, tags map[string]string, elem interface{}) interface{} {
+	if val == "" || val == "0" || val == "false" || val == "no" {
+		return false
+	}
+	return true
+}
+
+func Direction(val string, tags map[string]string, elem interface{}) interface{} {
+	if val == "1" || val == "yes" || val == "true" {
+		return 1
+	} else if val == "-1" {
+		return -1
+	} else {
+		return 0
+	}
+}
+
 func main() {
 	// 	data := `
 	// {
diff --git a/db/postgis.go b/db/postgis.go
index 92c3a5c..850f45a 100644
--- a/db/postgis.go
+++ b/db/postgis.go
@@ -22,8 +22,9 @@ type DB interface {
 }
 
 type ColumnSpec struct {
-	Name string
-	Type string
+	Name  string
+	Type  string
+	Value func(string, map[string]string, interface{}) interface{}
 }
 type TableSpec struct {
 	Name         string
@@ -65,7 +66,11 @@ func (spec *TableSpec) WayValues(way element.Way) []interface{} {
 		if !ok {
 			values = append(values, nil)
 		} else {
-			values = append(values, v)
+			if col.Value != nil {
+				values = append(values, col.Value(v, way.Tags, way))
+			} else {
+				values = append(values, v)
+			}
 		}
 	}
 	return values
@@ -216,7 +221,7 @@ func (pg *PostGIS) InsertWays(ways []element.Way, spec TableSpec) error {
 	for _, w := range ways {
 		_, err := stmt.Exec(spec.WayValues(w)...)
 		if err != nil {
-			return &SQLInsertError{SQLError{sql, err}, w}
+			return &SQLInsertError{SQLError{sql, err}, spec.WayValues(w)}
 		}
 	}
 
diff --git a/goposm.go b/goposm.go
index 9196cc6..1b6ad28 100644
--- a/goposm.go
+++ b/goposm.go
@@ -248,26 +248,27 @@ func main() {
 		waitFill := sync.WaitGroup{}
 		wayChan := make(chan []element.Way)
 		waitDb := &sync.WaitGroup{}
-		config := db.Config{
+		conf := db.Config{
 			Type:             "postgres",
 			ConnectionParams: *connection,
 			Srid:             3857,
 			Schema:           "public",
 		}
-		pg, err := db.Open(config)
+		pg, err := db.Open(conf)
 		if err != nil {
 			log.Fatal(err)
 		}
 		specs := []db.TableSpec{
 			{
 				"goposm_test",
-				config.Schema,
+				conf.Schema,
 				[]db.ColumnSpec{
-					{"name", "VARCHAR"},
-					{"highway", "VARCHAR"},
+					{"name", "VARCHAR", nil},
+					{"highway", "VARCHAR", nil},
+					{"oneway", "SMALLINT", config.Direction},
 				},
 				"GEOMETRY",
-				config.Srid,
+				conf.Srid,
 			},
 		}
 		err = pg.Init(specs)