I also talk about 3 layers architecture
YUKING
The 3-layer architecture, I think in fact, the 3-layer architecture is divided by a data information in the information system: 1. User Services (Data "exhibits data that meets this condition in a certain condition) 2. Business logic service (various records set in one way to user needs) 3. Database (Data Source) Today, the implementation of the company's development, the 3-layer architecture, in VB, COM works, enterprises have widely used COM, DCOM (distributed part object model) to connect all levels of services and applications, because The flexibility of COM (reused, transfer), structural clarity (specific block implementation). COM allows developers to be built in various levels of this application model in binary software components. It allows the application developers to use parts by encapsulating code or functions, whether one user interface control or business components. One component has one or more "interface", which can expose a set of methods or attributes and can therefore be called by other components or applications. For example, I analyzed the 3-layer architecture which represents the company's part CLSCompany, some of its properties (by get, let-be read or writable) such as: private mcode as string table properties: company code and Class's default event ternimate Indicates the behavior after the object, INITIALIZE indicates the behavior of the object, and the object can have a method, that is, add a common process in the class module (public sub () non-return value, public function x () AS XXX has a return value) Such as: Public function OpenAll () as boolean is a method of opening all records of a table of a database. Custom events are in the class module declaration section to declare events, use the RaiseEvent to stimulate events, use WitHevent to declare some objects in the module of the form of FRMCompany apps this class.
