diff --git a/docs/QuickStart.md b/docs/QuickStart.md
index 2b1f5829..a53673e1 100644
--- a/docs/QuickStart.md
+++ b/docs/QuickStart.md
@@ -58,7 +58,7 @@ engine, err = xorm.NewEngine("sqlite3", "./test.db")
 defer engine.Close()
 ```
 
-Generally, you can only create one engine. Engine supports run on go routines.
+You can create many engines for different databases.Generally, you just need create only one engine. Engine supports run on go routines.
 
 xorm supports four drivers now:
 
diff --git a/docs/QuickStartCn.md b/docs/QuickStartCn.md
index e5734824..607bdda6 100644
--- a/docs/QuickStartCn.md
+++ b/docs/QuickStartCn.md
@@ -62,7 +62,7 @@ engine, err = xorm.NewEngine("sqlite3", "./test.db")
 defer engine.Close()
 ```
 
-一般如果只针对一个数据库进行操作，只需要创建一个Engine即可。Engine支持在多GoRutine下使用。
+你可以创建一个或多个engine, 不过一般如果操作一个数据库，只需要创建一个Engine即可。Engine支持在多GoRutine下使用。
 
 xorm当前支持五种驱动四个数据库如下：
 
diff --git a/engine.go b/engine.go
index 671c1b87..50b45a78 100644
--- a/engine.go
+++ b/engine.go
@@ -34,8 +34,7 @@ type Engine struct {
 	ShowErr   bool
 	ShowDebug bool
 	ShowWarn  bool
-	//Pool      IConnectPool
-	//Filters []core.Filter
+
 	Logger     ILogger // io.Writer
 	TZLocation *time.Location
 }
@@ -456,15 +455,6 @@ func (engine *Engine) autoMap(bean interface{}) *core.Table {
 	return engine.autoMapType(v)
 }
 
-/*func (engine *Engine) mapType(t reflect.Type) *core.Table {
-	return mappingTable(t, engine.TableMapper, engine.ColumnMapper, engine.dialect, engine.TagIdentifier)
-}*/
-
-/*
-func mappingTable(t reflect.Type, tableMapper core.IMapper, colMapper core.IMapper, dialect core.Dialect, tagId string) *core.Table {
-	table := core.NewEmptyTable()
-	table.Name = tableMapper.Obj2Table(t.Name())
-*/
 func addIndex(indexName string, table *core.Table, col *core.Column, indexType int) {
 	if index, ok := table.Indexes[indexName]; ok {
 		index.AddColumn(col.Name)
@@ -524,17 +514,19 @@ func (engine *Engine) mapType(v reflect.Value) *core.Table {
 				if tags[0] == "-" {
 					continue
 				}
-				if (strings.ToUpper(tags[0]) == "EXTENDS") &&
-					(fieldType.Kind() == reflect.Struct) {
+				if strings.ToUpper(tags[0]) == "EXTENDS" {
+					fieldValue = reflect.Indirect(fieldValue)
+					if fieldValue.Kind() == reflect.Struct {
+						//parentTable := mappingTable(fieldType, tableMapper, colMapper, dialect, tagId)
+						parentTable := engine.mapType(fieldValue)
+						for _, col := range parentTable.Columns() {
+							col.FieldName = fmt.Sprintf("%v.%v", fieldValue.Type().Name(), col.FieldName)
+							table.AddColumn(col)
+						}
 
-					//parentTable := mappingTable(fieldType, tableMapper, colMapper, dialect, tagId)
-					parentTable := engine.mapType(fieldValue)
-					for _, col := range parentTable.Columns() {
-						col.FieldName = fmt.Sprintf("%v.%v", fieldType.Name(), col.FieldName)
-						table.AddColumn(col)
+						continue
 					}
-
-					continue
+					//TODO: warning
 				}
 
 				indexNames := make(map[string]int)
@@ -701,7 +693,7 @@ func (engine *Engine) IsTableEmpty(bean interface{}) (bool, error) {
 	session := engine.NewSession()
 	defer session.Close()
 	rows, err := session.Count(bean)
-	return rows > 0, err
+	return rows == 0, err
 }
 
 // If a table is exist
diff --git a/session.go b/session.go
index c1074601..921849eb 100644
--- a/session.go
+++ b/session.go
@@ -2947,7 +2947,7 @@ func (session *Session) Update(bean interface{}, condiBean ...interface{}) (int6
 		session.Statement.RefTable = table
 
 		if session.Statement.ColumnStr == "" {
-			colNames, args = buildConditions(session.Engine, table, bean, false, false,
+			colNames, args = buildUpdates(session.Engine, table, bean, false, false,
 				false, false, session.Statement.allUseBool, session.Statement.useAllCols,
 				session.Statement.mustColumnMap)
 		} else {
diff --git a/statement.go b/statement.go
index 5c08a7f9..1ae46f3d 100644
--- a/statement.go
+++ b/statement.go
@@ -253,6 +253,174 @@ func (statement *Statement) Table(tableNameOrBean interface{}) *Statement {
     return results
 }*/
 
+// Auto generating conditions according a struct
+func buildUpdates(engine *Engine, table *core.Table, bean interface{},
+	includeVersion bool, includeUpdated bool, includeNil bool,
+	includeAutoIncr bool, allUseBool bool, useAllCols bool,
+	mustColumnMap map[string]bool) ([]string, []interface{}) {
+
+	colNames := make([]string, 0)
+	var args = make([]interface{}, 0)
+	for _, col := range table.Columns() {
+		if !includeVersion && col.IsVersion {
+			continue
+		}
+		if col.IsCreated {
+			continue
+		}
+		if !includeUpdated && col.IsUpdated {
+			continue
+		}
+		if !includeAutoIncr && col.IsAutoIncrement {
+			continue
+		}
+		//
+		//fmt.Println(engine.dialect.DBType(), Text)
+		if engine.dialect.DBType() == core.MSSQL && col.SQLType.Name == core.Text {
+			continue
+		}
+		fieldValuePtr, err := col.ValueOf(bean)
+		if err != nil {
+			engine.LogError(err)
+			continue
+		}
+
+		fieldValue := *fieldValuePtr
+		fieldType := reflect.TypeOf(fieldValue.Interface())
+
+		requiredField := useAllCols
+		if b, ok := mustColumnMap[strings.ToLower(col.Name)]; ok {
+			if b {
+				requiredField = true
+			} else {
+				continue
+			}
+		}
+
+		if fieldType.Kind() == reflect.Ptr {
+			if fieldValue.IsNil() {
+				if includeNil {
+					args = append(args, nil)
+					colNames = append(colNames, fmt.Sprintf("%v=?", engine.Quote(col.Name)))
+				}
+				continue
+			} else if !fieldValue.IsValid() {
+				continue
+			} else {
+				// dereference ptr type to instance type
+				fieldValue = fieldValue.Elem()
+				fieldType = reflect.TypeOf(fieldValue.Interface())
+				requiredField = true
+			}
+		}
+
+		var val interface{}
+		switch fieldType.Kind() {
+		case reflect.Bool:
+			if allUseBool || requiredField {
+				val = fieldValue.Interface()
+			} else {
+				// if a bool in a struct, it will not be as a condition because it default is false,
+				// please use Where() instead
+				continue
+			}
+		case reflect.String:
+			if !requiredField && fieldValue.String() == "" {
+				continue
+			}
+			// for MyString, should convert to string or panic
+			if fieldType.String() != reflect.String.String() {
+				val = fieldValue.String()
+			} else {
+				val = fieldValue.Interface()
+			}
+		case reflect.Int8, reflect.Int16, reflect.Int, reflect.Int32, reflect.Int64:
+			if !requiredField && fieldValue.Int() == 0 {
+				continue
+			}
+			val = fieldValue.Interface()
+		case reflect.Float32, reflect.Float64:
+			if !requiredField && fieldValue.Float() == 0.0 {
+				continue
+			}
+			val = fieldValue.Interface()
+		case reflect.Uint8, reflect.Uint16, reflect.Uint, reflect.Uint32, reflect.Uint64:
+			if !requiredField && fieldValue.Uint() == 0 {
+				continue
+			}
+			val = fieldValue.Interface()
+		case reflect.Struct:
+			if fieldType == reflect.TypeOf(time.Now()) {
+				t := fieldValue.Interface().(time.Time)
+				if !requiredField && (t.IsZero() || !fieldValue.IsValid()) {
+					continue
+				}
+				val = engine.FormatTime(col.SQLType.Name, t)
+				//fmt.Println("-------", t, val, col.Name)
+			} else {
+				engine.autoMapType(fieldValue)
+				if table, ok := engine.Tables[fieldValue.Type()]; ok {
+					if len(table.PrimaryKeys) == 1 {
+						pkField := reflect.Indirect(fieldValue).FieldByName(table.PKColumns()[0].FieldName)
+						if pkField.Int() != 0 {
+							val = pkField.Interface()
+						} else {
+							continue
+						}
+					} else {
+						//TODO: how to handler?
+					}
+				} else {
+					val = fieldValue.Interface()
+				}
+			}
+		case reflect.Array, reflect.Slice, reflect.Map:
+			if fieldValue == reflect.Zero(fieldType) {
+				continue
+			}
+			if fieldValue.IsNil() || !fieldValue.IsValid() || fieldValue.Len() == 0 {
+				continue
+			}
+
+			if col.SQLType.IsText() {
+				bytes, err := json.Marshal(fieldValue.Interface())
+				if err != nil {
+					engine.LogError(err)
+					continue
+				}
+				val = string(bytes)
+			} else if col.SQLType.IsBlob() {
+				var bytes []byte
+				var err error
+				if (fieldType.Kind() == reflect.Array || fieldType.Kind() == reflect.Slice) &&
+					fieldType.Elem().Kind() == reflect.Uint8 {
+					if fieldValue.Len() > 0 {
+						val = fieldValue.Bytes()
+					} else {
+						continue
+					}
+				} else {
+					bytes, err = json.Marshal(fieldValue.Interface())
+					if err != nil {
+						engine.LogError(err)
+						continue
+					}
+					val = bytes
+				}
+			} else {
+				continue
+			}
+		default:
+			val = fieldValue.Interface()
+		}
+
+		args = append(args, val)
+		colNames = append(colNames, fmt.Sprintf("%v=?", engine.Quote(col.Name)))
+	}
+
+	return colNames, args
+}
+
 // Auto generating conditions according a struct
 func buildConditions(engine *Engine, table *core.Table, bean interface{},
 	includeVersion bool, includeUpdated bool, includeNil bool,