NET中的ORM設(shè)計(jì)與實(shí)現(xiàn)

論文字?jǐn)?shù):11607,頁數(shù):30  有開題報(bào)告，任務(wù)書

摘    要
 面向?qū)ο笤O(shè)計(jì)和關(guān)系型數(shù)據(jù)庫設(shè)計(jì)存在很大的不同, 因?yàn)閷ο竽Ｐ秃完P(guān)系模型兩者之間存在“阻抗不匹配”的現(xiàn)象。面向?qū)ο笤O(shè)計(jì)的理論包括封裝、關(guān)聯(lián)、聚合、繼承、多態(tài)，而關(guān)系數(shù)據(jù)庫主要針對數(shù)據(jù)的存儲，其數(shù)學(xué)依據(jù)是關(guān)系模型。我們希望可以實(shí)現(xiàn)通過面向?qū)ο蟮脑O(shè)計(jì)方式來完成業(yè)務(wù)流程，但是必須考慮的最終如何把對象保存下來。如果存貯介質(zhì)采用關(guān)系型數(shù)據(jù)庫，那么當(dāng)我們將對象保存到關(guān)系型數(shù)據(jù)庫的時(shí)候，矛盾也就出現(xiàn)了，這也是我們要做OR－Mapping的主要原因——架起對象和關(guān)系型數(shù)據(jù)庫的橋梁。ORM（Object-Relation Mapping）主要解決對象層次的映射、對象關(guān)系的映射以及對象的持久化問題。它試圖將實(shí)體對象的狀態(tài)映射到RDBMS的數(shù)據(jù)上，以提供一種透明的持久化操作。
 
關(guān)鍵詞： 面向?qū)ο?關(guān)系數(shù)據(jù)庫,持久化,對象關(guān)系映射
A Design and Implementation of ORM with .NET

 Abstract
 There is great difference between Object-Oriented Design and Database System Design, because of the Impedance Mismatch between Object Model and Relation Model. Object-oriented design theory includes packaging, relevance, polymerization, inheritance and polymorphism, while Relation Database System(RDBS) mainly focusing on data storage, based on a mathematical relation model. We hope to accomplish business processes through the design of object-oriented methods, this is available. However, it must be considered that how to storage the data. If the storage medium is relational database, the contradictions occur when save the object data as a relation model. This is the main reason we need O-R Mapping which is a bridge between object and relational database. ORM includes object level mapping, object relation mapping and object persistence. It tries to map the entities state to the RDBMS data, in order to support a series of transparent persistency operations.

 Key Words:  Object-Oriented; RDBS; Object-Relation Mapping; persistency 
 
 
 
 目    錄
1 緒論 1
1.1 課題的背景及目的 1
1.2 國內(nèi)外研究狀況 1
1.3 課題研究方法 1
1.4 論文構(gòu)成及研究內(nèi)容 2
2 對象關(guān)系映射簡介 3
2.1 對象之間的關(guān)系 3
2.2 關(guān)系數(shù)據(jù)庫的關(guān)系 4
2.3 映射策略 4
2.3.1 繼承映射模式 4
2.3.2 關(guān)聯(lián)映射模式 5
2.3.3 聚合映射模式 6
2.3.4 一對一關(guān)聯(lián)、一對多關(guān)聯(lián) 7
2.3.5 多對多關(guān)聯(lián) 8
2.4 面向?qū)ο蟮臄?shù)據(jù)庫設(shè)計(jì) 8
3 設(shè)計(jì)與實(shí)現(xiàn)要點(diǎn) 9
3.1 將屬性映射成列 10
3.2 將類映射成表 12
3.2.1 整個(gè)類層次結(jié)構(gòu)使用一個(gè)數(shù)據(jù)實(shí)體 13
3.2.2 每個(gè)具體類使用一個(gè)數(shù)據(jù)實(shí)體 13
3.2.3 每個(gè)類使用一個(gè)數(shù)據(jù)實(shí)體 14
3.2.4 比較并選取映射策略 15
3.3 跨多種數(shù)據(jù)庫能力 17
3.4 運(yùn)行時(shí)動(dòng)態(tài)產(chǎn)生SQL語句的實(shí)現(xiàn) 19
總結(jié) 23
致謝 24
參考文獻(xiàn) 25