diff --git a/nilable_structs.go b/nilable_structs.go
index e77663a..8ce06f4 100644
--- a/nilable_structs.go
+++ b/nilable_structs.go
@@ -2,29 +2,10 @@ package gobatis
 
 import (
 	"database/sql"
-	"database/sql/driver"
-	"time"
 )
 
 type NullBool = sql.NullBool
 type NullFloat64 = sql.NullFloat64
 type NullInt64 = sql.NullInt64
 type NullString = sql.NullString
-
-// There is implementation of this in lib/pg
-type NullTime struct {
-	Time  time.Time
-	Valid bool // Valid is true if Time is not NULL
-}
-// Scan implements the Scanner interface.
-func (nt *NullTime) Scan(value interface{}) error {
-	nt.Time, nt.Valid = value.(time.Time)
-	return nil
-}
-// Value implements the driver Valuer interface.
-func (nt NullTime) Value() (driver.Value, error) {
-	if !nt.Valid {
-		return nil, nil
-	}
-	return nt.Time, nil
-}
+type NullTime = sql.NullTime
diff --git a/proc_params.go b/proc_params.go
index b64410d..674070a 100644
--- a/proc_params.go
+++ b/proc_params.go
@@ -144,6 +144,10 @@ func structToMap(s interface{}) map[string]interface{} {
 
 func fieldToVal(field interface{}) (interface{}, bool) {
 	objVal := reflect.ValueOf(field)
+	if objVal.IsNil() {
+		return nil, false
+	}
+
 	if objVal.Kind() == reflect.Ptr {
 		objVal = objVal.Elem()
 	}
@@ -151,48 +155,36 @@ func fieldToVal(field interface{}) (interface{}, bool) {
 	tp := objVal.Type()
 	switch tp.Name() {
 	case "Time":
-		if nil != field {
-			return field.(time.Time).Format("2006-01-02 15:04:05"), true
-		}
+		return field.(time.Time).Format("2006-01-02 15:04:05"), true
 	case "NullString":
-		if nil != field {
-			ns := field.(NullString)
-			if ns.Valid {
-				str, _ := ns.Value()
-				return str, true
-			}
+		ns := field.(NullString)
+		if ns.Valid {
+			str, _ := ns.Value()
+			return str, true
 		}
 	case "NullInt64":
-		if nil != field {
-			ni64 := field.(NullInt64)
-			if ni64.Valid {
-				i, _ := ni64.Value()
-				return i, true
-			}
+		ni64 := field.(NullInt64)
+		if ni64.Valid {
+			i, _ := ni64.Value()
+			return i, true
 		}
 	case "NullBool":
-		if nil != field {
-			nb := field.(NullBool)
-			if nb.Valid {
-				b, _ := nb.Value()
-				return b, true
-			}
+		nb := field.(NullBool)
+		if nb.Valid {
+			b, _ := nb.Value()
+			return b, true
 		}
 	case "NullFloat64":
-		if nil != field {
-			nf := field.(NullFloat64)
-			if nf.Valid {
-				f, _ := nf.Value()
-				return f, true
-			}
+		nf := field.(NullFloat64)
+		if nf.Valid {
+			f, _ := nf.Value()
+			return f, true
 		}
 	case "NullTime":
-		if nil != field {
-			nt := field.(NullTime)
-			if nt.Valid {
-				t, _ := nt.Value()
-				return t.(time.Time).Format("2006-01-02 15:04:05"), true
-			}
+		nt := field.(NullTime)
+		if nt.Valid {
+			t, _ := nt.Value()
+			return t.(time.Time).Format("2006-01-02 15:04:05"), true
 		}
 	default:
 		return field, true
diff --git a/util.go b/util.go
index 27e9886..e32b91d 100644
--- a/util.go
+++ b/util.go
@@ -2,6 +2,31 @@ package gobatis
 
 import "time"
 
+// PI64 to NullInt64
+func PI64(i int64) *int64 {
+	return &i
+}
+
+// PS to NullString
+func PS(s string) *string {
+	return &s
+}
+
+// PF64 to NullFloat64
+func PF64(f float64) *float64 {
+	return &f
+}
+
+// PT to NullTime
+func PT(t time.Time) *time.Time {
+	return &t
+}
+
+// NB to NullBool
+func PB(b bool) *bool {
+	return &b
+}
+
 // NI64 to NullInt64
 func NI64(i int64) NullInt64 {
 	return NullInt64{Int64: i, Valid: true}