Feature: implement the time precison for time.Time type

pkg/client/orm/cmd_utils.go

@@ -66,7 +66,12 @@ checkColumn:
 	case TypeDateField:
 		col = T["time.Time-date"]
 	case TypeDateTimeField:
+		if fi.timePrecision == nil {
 			col = T["time.Time"]
+		} else {
+			s := T["time.Time-precision"]
+			col = fmt.Sprintf(s, *fi.timePrecision)
+		}
 	case TypeBitField:
 		col = T["int8"]
 	case TypeSmallIntegerField:

pkg/client/orm/db_mysql.go

@@ -60,6 +60,7 @@ var mysqlTypes = map[string]string{
 	"uint64":              "bigint unsigned",
 	"float64":             "double precision",
 	"float64-decimal":     "numeric(%d, %d)",
+	"time.Time-precision": "datetime(%d)",
 }
 
 // mysql dbBaser implementation.

pkg/client/orm/db_oracle.go

@@ -50,6 +50,7 @@ var oracleTypes = map[string]string{
 	"uint64":              "INTEGER",
 	"float64":             "NUMBER",
 	"float64-decimal":     "NUMBER(%d, %d)",
+	"time.Time-precision": "TIMESTAMP(%d)",
 }
 
 // oracle dbBaser

pkg/client/orm/db_postgres.go

@@ -59,6 +59,7 @@ var postgresTypes = map[string]string{
 	"float64-decimal":     "numeric(%d, %d)",
 	"json":                "json",
 	"jsonb":               "jsonb",
+	"time.Time-precision": "timestamp(%d) with time zone",
 }
 
 // postgresql dbBaser.

pkg/client/orm/models_info_f.go

@@ -137,6 +137,7 @@ type fieldInfo struct {
 	isFielder           bool // implement Fielder interface
 	onDelete            string
 	description         string
+	timePrecision       *int
 }
 
 // new field info
@@ -177,7 +178,7 @@ func newFieldInfo(mi *modelInfo, field reflect.Value, sf reflect.StructField, mN
 	decimals := tags["decimals"]
 	size := tags["size"]
 	onDelete := tags["on_delete"]
-
+	precision := tags["precision"]
 	initial.Clear()
 	if v, ok := tags["default"]; ok {
 		initial.Set(v)
@@ -377,6 +378,18 @@ checkType:
 		fi.index = false
 		fi.unique = false
 	case TypeTimeField, TypeDateField, TypeDateTimeField:
+		if fieldType == TypeDateTimeField {
+			if precision != "" {
+				v, e := StrTo(precision).Int()
+				if e != nil {
+					err = fmt.Errorf("convert %s to int error:%v", precision, e)
+				} else {
+					fi.timePrecision = &v
+				}
+			}
+
+		}
+
 		if attrs["auto_now"] {
 			fi.autoNow = true
 		} else if attrs["auto_now_add"] {

pkg/client/orm/models_utils.go

@@ -45,6 +45,7 @@ var supportTag = map[string]int{
 	"on_delete":    2,
 	"type":         2,
 	"description":  2,
+	"precision":    2,
 }
 
 // get reflect.Type name with package path.