Logical design(2)
纸业专业英语词汇翻译（D2）
纸业专业英语词汇翻译(D2)degradation 降解acid degradation 酸性降解alkaline degradation 碱性降解bacterriological degradation 细菌降解cellulose degradation 纤维素降解chemical degradation 化学降解enzymatic degradation 酶催降解fermentative degradation 发酵降解hyduolytic degradation 水解降解light degradation 光降解mechanicaldegradation 机械降解microbiological degradation 微生物降解oxidative degradation 氧化降解physical degradation 物理降解thermal degradation 热降解ultrasonic wave degradation 超声波降解degradation product 降解产物degradation reaction 降解反应degradative 降解的degradative reduction 降解还原（作用）degraded cellulose 降解纤维素degraded rags 低级破布degree of beating 打浆度degree of bleaching 漂白度degree of cooking 蒸煮度degree of crook 弯曲程度degree of curing 熟化程度degree of curling 卷曲度degree of dispersion 分散程度degree of fermentation 发酵程度degree of hydration 水化度degree of non-combustibility 不可燃烧度degree fo non-flammability 不可燃烧度degree of orientation 定向（程）度，取向度degree of polymerization 聚合度degree of redution 还原率degree of saturation 饱合度degree of sizing 施胶度degree of slippiness 滑脱度degree of substitution 取代度degree of wetness 湿润度degree of whiteness 白度degum 脱胶dehumidifier 减湿器dehmidify 减湿dehydrate 脱水dehydrater 脱水器；脱水剂dehydrating agent 脱水剂dehydration 脱水（作用）dehydro-abietic acid 脱氢松香酸dehydrogenation 脱氢（作用）deink 脱墨deinded newspuint 脱墨新闻纸deinded stock 脱墨浆料deinked waste 脱墨废纸deinking 脱墨deionization 消除电离作用delaminate 脱层delaminated clay 涂布粘土delamination 脱层（作用）delamination resistance 抗脱层性能delay time 延迟时间delignification 脱木素（作用）dilignify 脱木素delimbing 砍伐枝桠deliquescence 潮解delivery 输送delivery gate 分送闸板delivery pipe 输送管delivery roll 输送辊，传递辊deita former 三角形长网成形器dcita wood 多层木dclthirna size 冷法松香胶deluge nozzle 压力喷嘴deluge tower 烟道气洗涤器deluge tower fume collector 塔式集尘器dilustering 褪光泽deluxe refiner 圆筒形精浆机demarcation 分界demethylation 脱甲基（作用）demy 英国纸张尺寸标准demy scale 象限秤den （打浆机）底刀座denaturant 变性剂denatured alcohol 变性酒精denaturing agent 变性剂dendrology 树木学denim cuttings 裁切布边dennison wax cennison 蜡棒dennison wax test dennison 蜡棒起毛试验dense timber 紧密木材dense wood 紧密木材densification 增浓（作用）densified laminated wood 硬化层秋材densimeter 密度计density 密度density measurement 测量密度density meter 密度计densometer 密度计；透气度测定仪denude 去污；溶蚀deodar ceder (cedrus deodara loud.) 雪松deodorization 除臭（作用）deodorize 除臭deodorizer 除臭器deoxidize 脱氧department 部门；车间depickling 脱酸depither 除髓机depithing 除髓depithing maching 除髓机deplete water 废水depolarization 去极（化）作用；消磁（作用）；消偏振（作用）depolymerize 解聚depolymerizing agent 解聚剂deposit 沉积；沉积物deposition 沉积（作用）depot 储存；基地depreciation 折旧depth 深度depth of burring 刻石深度deragger （水力碎浆机）绞绳装置derivative 衍生物dermatogen 表皮原质dermatosomen 原皮质descabing 去除瑕疵descending chromatography 下行色谱法desensitization 减敏感作用desert gum(eucalytus rudis) 野桉desiccant 干燥的；干燥剂desiccate 干燥desiccate wood 烘干木材deseccating agent 干燥剂desiccation 干燥（作用）desiccative 干燥的desiccator 干燥器design 设计；计算；计划；装置design data 设计数据；设计资料design roll 水印辊design speed 设计速度designation number 标志数；标准指数desk calculator 台式计算器desorption 解吸destrutive distillation 干馏，分解蒸馏desuperheater 过热（蒸汽）降温器details 细节；零件；元件detection 检测；检验；探测detergent 去垢剂；去污剂deteriorate 降低；退化；损坏；消耗；变质deterioration 降低；退化；损坏；消耗；变质detoxicate 解毒；去除污染detoxication 解毒；去除污染detoxification 解毒；去除污染detoxify 解毒；去除污染developer 显影剂development of strength propcrties 纸张强度发展特性，纸张强度增特性devil 除尘机devillicate 帚化纤维，分裂纤维dew point 露点dewater 脱水dewatering 脱水，去水dewatering cylinder 脱水圆网dewatering drum 脱水转鼓dewaxing 脱蜡dextrin(e)(gum) 糊精dextrose 右旋糖；葡萄糖diagnosis 判断；诊断diagonal cutter 斜向裁切机diagonal grain 直纹dial 刻度盘；调节控制盘；拨号盘；二醛dial micrometer 测微仪，千分刻度盘；厚度千分仪dialdehyde cellulose 双醛纤维素dialdehyde starch 双醛淀粉dialysis 渗析diameter accretion 直径增长diameter class 径级diameter increment 直径增量diamond 金刚石，菱形diamond cut burr 菱形刻石刀diaphanometer 不透明度测定diaphragm 隔膜；薄膜diaphragm pump 隔膜泵diaphragm screen 平板筛浆机，平筛diatom 硅藻diatomaceous earth 硅藻土diatomaceous silica 硅藻土datomite 硅藻土diazo compound 重氮化合物diazo coupling 重氮偶合diazotization 重氮化（作用）diazotized compound 重氮化合物dibasic aluminum monorosinate 单松香酸铝二代盐dichloroethane 二氯乙烷dichloromethane 二氯甲烷dicotyledon 双子叶植物dicotyledonous 双子叶木材dicyandiamide 双氰胺，二聚氨基氰die 模；塑模die casting 模铸die cut 打孔；模切，冲动die cut box 打孔纸箱die cut card 打孔卡die cut liner 打孔衬里纸die cut ragchine 模压切割机die cutter 模压切割机die cutting 打孔；模切，冲切die embossing 模压印花die stamping 模压印花dielectric 介电dielectric constant 介电常数dielectric drying 介电干燥dielectric heating 介电加热dielectric loss 介电损失dielectric properties 介电性质dielectric strength 介电强度dielectrical properties 介电性质dielectric strength 介电强度dielectrical properties 介电性质diethyl ether 二乙醚difference spectrum 差异光谱differential draw indicater 差动牵引指示计differential drive 差速传动differential flowmeter 差示流量计differential gear 差动齿轮differential manometer 差示压力计differential pressure regulator 差动压力调节器differential valve 差动阀differential winder 差动复卷机diffraction 绕射，衍射diffuse 扩射；漫射diffuse blue reflectance fator 蓝光扩散反射系数（即iso亮度）diffuse (in aggregates)parenchyma 星散薄壁细胞diffuse porous wood 散孔木diffuse 扩张器；浸渍器；扩散洗涤器diffuse washer 扩散洗涤器diffuse washing 扩散洗涤diffusion 扩散作用diffusion-extraction method of blowing 扩散抽液法喷放diffusion washer 扩散洗涤器diffusion washing 扩散洗涤diffusion zone 扩散区digest 蒸煮digester 蒸煮器digester acid 蒸煮酸digester blow test 蒸煮终点测定digester brick 耐酸砖digester capacity 蒸煮锅容积digester charge 蒸煮锅装料digester charging 蒸煮锅装料digester charging floor 蒸煮锅装料楼面digester circulating system 蒸煮药液循环系统digester circulating 蒸煮药液循环digester controller 蒸煮（程序）控制装置digester cycle 蒸煮周期digester filling 蒸煮锅装料digester fittings 蒸煮锅管件digester head 蒸煮锅锅口digester house 蒸煮车间digester (inside) test 放气前蒸煮液分析digester lining 蒸煮锅衬里digester liquor 蒸煮液digester neck 蒸煮锅锅颈digester operater 蒸煮锅生产能力digester relief （蒸煮锅）放气；放气管路digester room 蒸煮车间digester shell 蒸煮锅锅壳，锅壁digester side relief 蒸煮锅侧面放气管路digester silo 蒸煮锅顶料仓digester steaming 蒸煮锅通汽digester tile 耐酸砖digester top relief 蒸煮锅锅顶放气digester yield 蒸煮得率，粗浆得率digesterman 蒸煮工digesting 蒸煮digestion 蒸煮digestion liquor 蒸煮液digestion operating curve 蒸煮曲线digestion time 蒸煮时间digger 挖浆机digging machine 挖浆机digging of pulp 挖浆digital computer 数字计算机digital speed/draw system 车速和牵引力的数字控制系统digital system 数字系统digitrac 数字控制器dihydro-abietic acid 二氢化松香酸di-isocyanate 二异氰酸盐dilatancy 膨胀性能dilatant 膨胀剂diluent 稀释剂dilute 稀释dilute acid 稀酸dilute solution 稀溶液dilution 稀释dilution factor 稀释因子dilution water 稀释（用）水dilution well 稀释槽。
Pearson Edexcel Level 2 数字应用Unit 1：开发网络产品说明书
Turn over Instructions• Comple e all activities.• You must not use the internet during this test.Information• There is ONE task in this examination paper, containing TWO activities.•T he ASSETS folder in your user area includes all the content and informationyou need.•The invigilator will tell you where to store your work.•You may use blank paper for design work.•The total mark is 50.•T he marks for each activity are shown in brackets– use this as a guide as to how much time to spend on each activity.Advice•Read the task and instructions on pages 2–3.•Save your work regularly.•Check your work.*P44457A*P44457A©2014 Pearson Education Ltd.1/1/1/12P44457ACLIENT BRIEFThe Recycle Drive is a national, government-run campaign. Its aim is to encourage recycling and reduce the amount of waste sent to landfills.The Recycle Drive requires a microsite aimed at encouraging schools and colleges to recycle paper and waste.The basis for the content and information for the microsite can be found in the ASSETS folder.Overall site requirements• Five pages:• home page• benefits of recycling page• recycling page that links to two further pages:• paper recycling page• compos t ing page.• Content must be visible without scrolling at a resolution of 1024 x 768 pixels.• A colour scheme that reflects the environmentally friendly theme of the campaign. • Facts about The Recycle Drive campaign, which should be taken from the INFO.rtf file,this text may be edited.• Images to be taken from the ASSETS folder, these may be edited.• Accessibility features for visually impaired users.• A consistent design across the microsite.Other requirementsPage template • A banner including a suitable title and the campaign logo(which should link to ).The banner should extend the full width of the page.• A navigation bar linking to: the home page, the benefits ofrecycling page and the recycling page.• The navigation bar should include the home page, benefitsand recycle icons (from the IMAGES folder) for the buttons.Each icon should be 60 x 60 pixels. Each icon will need to beedited to create a rollover button.File formats • Images to be in .png format and each individual image mustbe less than 300 KB.• Video file to remain in .mov format.3P44457A Composting page •Include COMPOST.png from the IMAGES folder on the composting page.•Include appropriate information about composting.• Edit the code so that COMPOST.png is positioned on the rightof the text and the text wraps around the image.Top tips • From the TOP_TIPS image, which can be found in the IMAGESfolder, choose one of the top tips to create a graphical linkthat:•shows only your chosen top tip •links to an image showing all the top tips• is included on the home ndscape • Edit the image LANDSCAPE.bmp, provided in the IMAGESfolder, to include The Recycle Drive logo and add someadditional appropriate text that you have written. Place theedited image on the benefits of recycling page. The editedimage must be in .png format.Video • The VIDEO.mov, included within the ASSETS folder, should beembedded on a suitable page, retaining its 4:3 ratio. The videoshould play only on click.Contacts •Add an email link for further information. The email addresscan be found in the INFO.rtf file in the ASSETS folder.THE TASK You must design and create a microsite for The Recycle Drive.You will need to create a page template to ensure consistency.You must include the requirements specified in the client brief.You should create a logical folder structure for your microsite files.In Activity 2, you will need to explain your design decisions, justify your choices and suggest further improvements as part of your evaluation.Activity 1Design, build and test the microsite.Note: you do not need to test any external links.(44)Activity 2Complete an evaluation of your microsite using the document EVALUATION.doc(6)(Total for Task = 50 marks)TOTAL FOR PAPER = 50 MARKS4P44457A BLANK PAGE。
2. Readability and Accessibility
Computerization (2)
This is in keeping with some research, which concludes that the sentence is not the unit for measure.
Software Programs
Today most grammar software programs provide more than one readability measure as well as comparisons to well-known writing. In addition to a qualitative assessment of the writing, Stylewriter, a plain-English editorial program, provides word and sentence statistics with an index percentage of the passive verbs used as well as a count words in various categories: complex, jargon, abstract, legal, tautologies, and so on.
Factors to Measure (1)
Research has been done to create algorithms that quantitatively assess the readability of a text. In the English versions of these algorithms, there are factors like the number of words per sentence and the average number of syllables per word. Readability formulas are usually based on one semantic factor (the difficulty of words) and one syntactic factor (the difficulty of sentences).
计算机科学与技术专业
计算机科学与技术专业目录1、《模拟电子电路》2、《数字逻辑电路》3、《电路分析》3、《计算机组成原理》4、《程序设计基础》5、《汇编语言课程》6、《计算机导论》7、《计算机辅助设计》8、《人工智能》9、《数据库系统原理课程》10、《算法设计与分析》11、《计算机网络原理》12、《计算机网络实用技术》13、《计算机图形学》14、《面向对象程序设计》15、《数据结构课程》16、《网络互连技术》17、《编译技术》18、《操作系统》19、《软件工程》模拟电子线路课程名称：模拟电子线路英文名称：Low Frequency Electron Circuitry课程编号：071651课程性质：（独立设课或非独立设课）非独立设课课程属性：专业验证课实验室名称：信息与通信技术实验室实验对象：专科生、本科生课程总学时：72 学分：4 实验总学时： 27 实验学分：国家统编、行业统编或自定：行业统编实验教材或指导书名称：模拟电子线路实验讲义一、课程简介：讲述用于处理模拟信号的电子电路的基本理论、基本知识、分析方法及设计方法，为以后学习“高频电子电路”等后续课程以及专业课打下良好的验证。
本课程主要内容包括：晶体管原理、模拟集成电路的原理、特性、模型；各种放大电路及其特性的分析、计算、设计，模拟集成电路调制解调器原理，数字调制解调器原理，模拟集成电路的基本单元电路、反馈放大器、集成运算放大器及其基本应用电路，锁相环原理二、课程实验目的与要求：运用课堂上所学的验证理论知识，分析实验现象。
实验中要明确实验目的，写出实验原理，测量方法，分析实验中观察到的现象，并进行总结（必写）。
三、考核（考试）方式：考查四、主要仪器设备：20M模拟双踪示波器、TPE-A型系列模拟电路实验箱、万用表、毫伏表等。
五、参考书目：『低频电子线路』、六、实验项目：大纲编写人：黎相成大纲审核人：大纲批准人：日期：2004年02月20日脉冲数字电路课程名称：脉冲数字电路英文名称：Digital System and Logical Design课程编号：071081课程性质：非独立设课课程属性：专业验证实验教材或指导书名称：脉冲与数字电路实验指导书课程总学时：72 学分：4 实验总学时：24 学分：1面向专业：计算机科学与技术电子信息工程通信工程电子商务实验室名称：信息与通信技术实验室一、课程内容：本课程是计算机与电子通信类专业的专业验证课，本课程内容包括：数字电路实验验证知识和常用仪器设备的使用，TTL与非门的参数测试、集成门电路的逻辑变换及应用，三态门、冒险现象，MSI组合功能件的应用，集成触发器及应用，MSI计数器及应用，555定时器及应用。
数据库系统概念(英文精编版.第六版)
Atomicity of updates
Failures
may lead to inconsistencies (1) account_A = account_A – 100 (2) account_B = account_B + 100
Example:
Concurrent access by multiple users
Exercises
Computer users interacts with data in the _______ level A. physical B. logical C. view D. all of the above Application users interact with data in the _______ level. A. physical B. logical C. view D. all of the above How the data are actually stored is called _______ A. Physical level B. Logical level C. View level D. Conceptual level
property is called ( )
A. Data inconsistency C. Data isolation B. Data redundancy D. Data integrity
1.3 View of Data
Hierarchy of Abstraction Levels
Three Abstraction Levels of Data
机械工业出版社
本课程学习内容
关系数据模型 关系数据库语言
AVTRONSYS VisLogic说明书
目录第一章简介 (3)1.1A VTRONSYS V ISUAL L OGICAL D ESIGN V2.80系列介绍 (3)1.2A VTRONSYS V ISUAL L OGICAL D ESIGN V2.80特色和设计理念 (3)1.3A VTRONSYS V ISUAL L OGICAL D ESIGN V2.80系统配置要求 (3)1.4A VTRONSYS V ISUAL L OGICAL D ESIGN V2.80启动和退出 (4)1.4.1 AVTRONSYS Visual Logical DesignV2.80的启动 (4)1.4.2 AVTRONSYS Visual Logical DesignV2.80的退出 (4)第二章A VTRONSYS VISUAL LOGICAL DESIGNV2.80工作环境 (5)2.1A VTRONSYS V ISUAL L OGICAL D ESIGN V2.80工作环境介绍 (5)2.1.2 AVTRONSYS Visual Logical DesignV2.80的菜单栏 (6)2.1.3 AVTRONSYS Visual Logical DesignV2.80的工具栏 (12)2.1.4 AVTRONSYS Visual Logical DesignV2.80的状态栏 (12)第三章A VTRONSYS VISUAL LOGICAL DESIGNV2.80的工程操作 (13)3.1A VTRONSYS V ISUAL L OGICAL D ESIGN V2.80普通工程操作 (13)3.1.1 AVTRONSYS Visual Logical DesignV2.80建立工程 (13)3.1.3 AVTRONSYS Visual Logical DesignV2.80加入模块 (14)3.2宏工程操作 (15)3.2.1建立一个宏工程 (15)3.2.2 加入模块 (16)第四章A VTRONSYS VISUAL LOGICAL DESIGNV2.80设备操作 (17)第五章A VTRONSYS VISUAL LOGICAL DESIGNV2.80逻辑模块操作 (20)5.1A VTRONSYS V ISUAL L OGICAL D ESIGN V2.80菜单 (20)5.2A VTRONSYS V ISUAL L OGICAL D ESIGN V2.80快捷键 (24)第一章简介1.1 AVTRONSYS Visual Logical DesignV2.80系列介绍A VTRONSYS系统的控制主机采用了Motorola公司最新的32位嵌入式处理器，并且运行实时的嵌入式操作系统，因此具有强大的数据处理能力和稳定可靠的机器性能，可广泛使用于工业、商业、教育、专业广播、医疗、娱乐及家庭等场合。
数据库部分术语对照
DB DesignSix Stages:1. Requirement Analysis（需求分析）2. Conceptual Design （概念设计）3. Logical Design （逻辑设计）4. Physical Design （物理设计）5. Implementation （实施）6. Running and maintenance （运行维护）数据字典Data Dictionary: Data item, Data Structure, Data Stream, Data storage, Data Process 聚集aggregation (is part of) 概括: generalization (is subset of)特殊化/概化specialization (is a)/ generalization (is subset of)子类/超类subclass/superclassDB Recovery事务：Transaction is action, or series of actions, carried out by user or application, which accesses or changes the contents of database. It is a logical unit of work with one or more SQL statements guaranteed to be atomic with respect to recovery.Four basic properties of a transaction are ACID (Atomicity, Consistency, Isolation, Durability) Transaction State (事务的状态)•Active, the initial state; the transaction stays in this state while it is executing•Partially committed, after the final statement has been executed.•Failed, after the discovery that normal execution can no longer proceed.•Aborted, after the transaction has been rolled back and the database restored to its state prior to the start of the transaction. Two options after it has been aborted:–restart the transaction – only if no internal logical error–kill the transaction•Committed, after successful completionTypes of Failures：•System crashes（系统故障，软故障）, resulting in loss of main memory.•Media failures（介质故障，硬故障）, resulting in loss of parts of secondary storage.•Transaction failure（事务故障）The log records are written before write to database, this rule is called Write-ahead log protocolRecovery Facilities ，DBMS should provide following facilities to assist with recovery: –Backup mechanism, which makes periodic backup copies of database.–Logging facilities, which keep track of current state of transactions and database changes.–Checkpoint facility, which enables updates to database in progress to be made permanent.–Recovery manager, which allows DBMS to restore database to consistent state following a failure.Log File contains information about all updates to database:–Transaction records.（Transaction identifier；Type of log record, (transaction start, insert, update, delete, abort, commit)；Identifier of data item affected bydatabase action ；Before-image of data item；After-image of data item, Time ofTransaction operation）Checkpoint records.Concurrency Control Technology （并发控制技术）Three Potential Problems Caused by Concurrency1．Lost update problem.（丢失更新）2．Uncommitted dependency problem（未提交依赖问题）.i.e. Dirty Read（读脏数据，uncommitted and then rollbacked data ）3．Inconsistent analysis problem.（不一致分析问题，不可重复读Non-repeatable read）i.e. Non-Repeatable ReadThe Two-Phase Locking Protocol（两段锁协议）Transaction follows 2PL protocol if all locking operations precede first unlock operation in the transaction.Two phases for transaction:–Growing phase - acquires all locks but cannot release any locks.–Shrinking phase - releases locks but cannot acquire any new locks.Or⏹Phase 1: Growing Phase（扩展阶段，申请锁阶段）❑transaction may obtain locks❑transaction may not release locks⏹Phase 2: Shrinking Phase（收缩阶段，释放锁阶段）❑transaction may release locks❑transaction may not obtain locksSerial Schedules （串行调度）serializable schedules （可串行化的调度）serializability可串行化Multiple Granularity 多粒度Compatibility Matrix 相容矩阵deadlocks 死锁livelock活锁Deadlock Detection 死锁检测。
数字逻辑 第2章课件
For outputs: logic 1 is light on logic 0 is light off. NOT uses a switch such that: logic 1 is switch open logic 0 is switch closed
Switches in series => AND
Normally-closed switch => NOT
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Boolean Algebra
An algebraic structure, L={K, +, •, -, 0, 1} defined on a set of logical variables, constant 0 and 1, and three binary operators (denoted +, ·and ) that satisfies the following axioms:
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Logic Gate Symbols and Behavior
Logic gates have special symbols:
Waveform behavior in time
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Gate Delay
In actual physical gates, if one or more input changes causes the output to change, the output change does not occur instantaneously. The delay between an input change(s) and the resulting output change is the gate delay denoted by tG:
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Multi-valued attributes
• A new table is created to hold the multi-valued attribute and the parent entity posts a copy of its primary key, to act as a foreign key. • Unless the multi-valued attribute is itself an alternate key of the parent entity, the primary key of the new table is composed of the multi-valued attribute and the original primary key of the parent entity.
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Mandatory participation on both sides of 1:1 relationship – (a) ER diagram; (b) as table
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Step 2.1 Map tables - Discuss using example ER
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Initial table structures for the entities
• In this case, the designation of the parent and child entities is arbitrary unless you can find out more about the relationship that can help you reach a decision one way or the other.
• The representation of a 1:* recursive relationship is similar to 1:* binary relationship. • However, in this case, both the parent and child entity is the same entity.
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Multi-valued attributes – ER diagram anol of Information Science and Engineering
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1:*binary relationships
• Entity on ‘one side’ of relationship is designated as the parent entity and entity on ‘many side’ is designated as child entity. • A copy of primary key of parent entity is placed into table representing the child entity, to act as a foreign key.
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Mandatory participation on both sides of 1:1 relationship
• Combine entities involved into one table and choose one of the primary keys of the original entities to be the primary key of the new table, while the other is used as an alternate key.
Logical design
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Step 2 Map ER model to tables - Tasks
• • • • • Step 2.1 Step 2.2 Step 2.3 Step 2.4 Step 2.5 Create tables Check table structures using normalization Check tables support user transactions Check business rules Review logical database design with users
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Optional participation on both sides of a 1:1 relationship – (a) ER diagram; (b) as tables
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Mandatory participation on one side of a 1:1 relationship
• Identify parent and child entities using participation constraints. • Entity with optional participation is parent entity, and entity with mandatory participation is child entity. • A copy of primary key of parent entity is placed in the table representing the child entity.
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1:* relationship – (a) ER diagram; (b) as tables
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1:* recursive relationships
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1:* recursive relationships – (a) ER diagram; (b) as tables
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1:1 binary relationships
• Consider how to create tables to represent the following participation constraints: • Mandatory participation on both sides of 1:1 relationship • Mandatory participation on one side of 1:1 relationship • Optional participation on both sides of 1:1 relationship.
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How to represent relationships
• Use primary key/foreign key mechanism. • In deciding where to post (or place) the foreign key attribute(s), must first identify the ‘parent’ and ‘child’ entities involved in the relationship. • The parent entity refers to the entity that posts a copy of its primary key into the table that represents the child entity, to act as the foreign key.
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How to represent relationships
• Consider how to represent the following relationships: – one-to-many (1:*) binary relationships; – one-to-many (1:*) recursive relationships; – one-to-one (1:1) binary relationships; – one-to-one (1:1) recursive relationships; – many-to-many (*:*) binary relationships; – complex relationships; Also, consider multi-valued attributes.
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Complex relationship – ER diagram
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