diff --git a/dialect_mysql.go b/dialect_mysql.go
index 15849abc..22f8b88d 100644
--- a/dialect_mysql.go
+++ b/dialect_mysql.go
@@ -3,7 +3,7 @@ package gorm
 import (
 	"fmt"
 	"reflect"
-	"strconv"
+	"strings"
 	"time"
 )
 
@@ -15,60 +15,69 @@ func (mysql) Quote(key string) string {
 	return fmt.Sprintf("`%s`", key)
 }
 
+// Get Data Type for MySQL Dialect
 func (mysql) DataTypeOf(field *StructField) string {
-	var (
-		size        int
-		dataValue   = reflect.Indirect(reflect.New(field.Struct.Type))
-		tagSettings = field.TagSettings
-	)
+	var dataValue, sqlType, size, additionalType = ParseFieldStructForDialect(field)
 
-	if num, ok := tagSettings["SIZE"]; ok {
-		size, _ = strconv.Atoi(num)
-	}
-
-	switch dataValue.Kind() {
-	case reflect.Bool:
-		return "boolean"
-	case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32:
-		if _, ok := tagSettings["AUTO_INCREMENT"]; ok {
-			return "int AUTO_INCREMENT"
-		}
-		return "int"
-	case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uintptr:
-		if _, ok := tagSettings["AUTO_INCREMENT"]; ok {
-			return "int unsigned AUTO_INCREMENT"
-		}
-		return "int unsigned"
-	case reflect.Int64:
-		if _, ok := tagSettings["AUTO_INCREMENT"]; ok {
-			return "bigint AUTO_INCREMENT"
-		}
-		return "bigint"
-	case reflect.Uint64:
-		if _, ok := tagSettings["AUTO_INCREMENT"]; ok {
-			return "bigint unsigned AUTO_INCREMENT"
-		}
-		return "bigint unsigned"
-	case reflect.Float32, reflect.Float64:
-		return "double"
-	case reflect.String:
-		if size > 0 && size < 65532 {
-			return fmt.Sprintf("varchar(%d)", size)
-		}
-		return "longtext"
-	case reflect.Struct:
-		if _, ok := dataValue.Interface().(time.Time); ok {
-			return "timestamp NULL"
-		}
-	default:
-		if _, ok := dataValue.Interface().([]byte); ok {
-			if size > 0 && size < 65532 {
-				return fmt.Sprintf("varbinary(%d)", size)
+	if sqlType == "" {
+		switch dataValue.Kind() {
+		case reflect.Bool:
+			sqlType = "boolean"
+		case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32:
+			if _, ok := field.TagSettings["AUTO_INCREMENT"]; ok || field.IsPrimaryKey {
+				sqlType = "int AUTO_INCREMENT"
+			} else {
+				sqlType = "int"
+			}
+		case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uintptr:
+			if _, ok := field.TagSettings["AUTO_INCREMENT"]; ok || field.IsPrimaryKey {
+				sqlType = "int unsigned AUTO_INCREMENT"
+			} else {
+				sqlType = "int unsigned"
+			}
+		case reflect.Int64:
+			if _, ok := field.TagSettings["AUTO_INCREMENT"]; ok || field.IsPrimaryKey {
+				sqlType = "bigint AUTO_INCREMENT"
+			} else {
+				sqlType = "bigint"
+			}
+		case reflect.Uint64:
+			if _, ok := field.TagSettings["AUTO_INCREMENT"]; ok || field.IsPrimaryKey {
+				sqlType = "bigint unsigned AUTO_INCREMENT"
+			} else {
+				sqlType = "bigint unsigned"
+			}
+		case reflect.Float32, reflect.Float64:
+			sqlType = "double"
+		case reflect.String:
+			if size > 0 && size < 65532 {
+				sqlType = fmt.Sprintf("varchar(%d)", size)
+			} else {
+				sqlType = "longtext"
+			}
+		case reflect.Struct:
+			if _, ok := dataValue.Interface().(time.Time); ok {
+				sqlType = "timestamp NULL"
+			}
+		default:
+			if _, ok := dataValue.Interface().([]byte); ok {
+				if size > 0 && size < 65532 {
+					sqlType = fmt.Sprintf("varbinary(%d)", size)
+				} else {
+					sqlType = "longblob"
+				}
 			}
-			return "longblob"
 		}
 	}
-	panic(fmt.Sprintf("invalid sql type %s (%s) for mysql", dataValue.Type().Name(), dataValue.Kind().String()))
+
+	if sqlType == "" {
+		panic(fmt.Sprintf("invalid sql type %s (%s) for mysql", dataValue.Type().Name(), dataValue.Kind().String()))
+	}
+
+	if strings.TrimSpace(additionalType) == "" {
+		return sqlType
+	}
+	return fmt.Sprintf("%v %v", sqlType, additionalType)
 }
 
 func (s mysql) currentDatabase(scope *Scope) (name string) {
diff --git a/dialect_sqlite3.go b/dialect_sqlite3.go
index 0bf2aa8c..d5ffb78d 100644
--- a/dialect_sqlite3.go
+++ b/dialect_sqlite3.go
@@ -13,9 +13,7 @@ type sqlite3 struct {
 
 // Get Data Type for Sqlite Dialect
 func (sqlite3) DataTypeOf(field *StructField) string {
-	var (
-		dataValue, sqlType, size, additionalType = ParseFieldStructForDialect(field)
-	)
+	var dataValue, sqlType, size, additionalType = ParseFieldStructForDialect(field)
 
 	if sqlType == "" {
 		switch dataValue.Kind() {