LP TRNH HNG I TNG NNG CAOM HNH A LP (Multi-Layers)

Ni dungPhn bit 3-tier, 3-layerVai tr v nhim v ca mi layerQun l ngoi l trong m hnh 3-layer

1-tier, 3-layer

2-tier, 3-layer

3-tier, 3-layerDataBusiness logicData AccessApplicationWebPhysical viewLogical view

Vai tr ca cc layerGUI (Presentation) Layer: Thu thp v hin th thng tin cho ngi dng cui.Khng s dng trc tip cc dch v ca lp Data Acces. S dng cc dch v do lp Business Logic cung cp. lp ny, chng ta c th b qua cc rng buc, cc logic nghip v ca ng dng.

Vai tr ca cc layerBusiness Logic Layer: Lp ny thc hin cc nghip v chnh ca h thng (V d: kim tra cc yu cu nghip v trc khi cp nht d liu)S dng cc dch v do lp Data Access cung cp.Cung cp cc dch v cho lp Presentation

Vai tr ca cc layerData Access Layer: Lp ny thc hin cc cng vic lin quan n lu tr v truy xut d liu ca ng dng.Cung cp cc dch v cho lp Business Logic s dng.S dng cc dch v ca cc h qun tr c s d liu nh MySql, SQL Server, Oracle, thc hin nhim v ca mnh.

Cc lu quan trngPhn bit vai tr Business Layer v khi nim x lMi Layer vn c x l ring, c trng ca Layer i khi vic quyt nh 1 x l nm layer no ch mang tnh cht tng i

Vic trao i lin lc gia cc layer

S ph thuc gia cc layer

Tnh cht ca m hnh 3-layerGim s kt dnh gia cc thc th phn mm (decoupling)Ti s dngChia s trch nhim

Qun l ngoi l

Qun l ngoi lNgoi l c th xy ra bt k layer noKhi ngoi l xy ra mt layer th:X l ni b trong layer Nm ngoi l ln layer cao hnKhng x lKhi mt layer nhn ngoi l t mt layer thp hnX l ni bNm ngoi l ln layer cao hnKhng x l

Pht trin ng dng

Pht trin ng dngBusiness Logic LayerData Access LayerData Transfer ObjectPresentation Layer

Pht trin ng dngCc lp DTONi dung mi lp gm:FieldsCc phng thc khi to.Cc phng thc set, getVD: SanPhamDTO, LoaiSanPhamDTO

Pht trin ng dngCc lp DALng vi mi bng trong database to mt class DAL tng ng.VD: SanPhamDAL, LoaiSanPhamDAL

Pht trin ng dngCc lp BLLTo cc class giao tip vi lp PresentationS dng cc dch v lp DAL x l nghip v.VD: SanPhamBLL, LoaiSanPhamBLL

Pht trin ng dngCc lp PLGiao tip vi ngi dng.S dng cc dch v do lp Business cung cp.VD: Xut ra mn hnh.

Pht trin ng dng

Pht trin ng dngDEMO