《计算机专业英语》课件第5章

UNIT5

TOPICS

TEXTAnIntroductiontoSQL

EXERCISES

SUPPLEMENTARYDatabaseManagementSystemandDatabaseModel

CONVERSATIONBookingHotels

WRITINGHowtoWriteBusinessContractTOPICS

Whatisdatabase?

WhatistheDBMS?

Whatisthedatabasemodel?

WhatistheSQL?HowmuchdoyouknowaboutNoSQL?

WhatisthefunctionofSQL?

Whatisthemainfutureofdatabase?

WhatiscomposedoftheDBMS?

Whatisthedistributeddatabase?

WhatarethelanguageelementsthatSQLlanguagesub-dividesinto?

Introduction

StructuredQueryLanguage,commonlyabbreviatedtoSQLandpronouncedassequel,isnotaconventionalcomputerprogramminglanguageinthenormalsenseofthephrase.WithSQLyoudon’twriteapplications,utilities,batchprocesses,GUIinterfacesoranyoftheothertypesofprogramforwhichyou’duselanguagessuchasVisualBasic,C++,Javaetc.InsteadSQLisalanguageusedexclusivelytocreate,manipulateandinterrogatedatabases.TEXT

AnIntroductiontoSQL

SQLisaboutdataandresults,eachSQLstatementreturnsaresult,whetherthatresultbeaquery,anupdatetoarecordorthecreationofadatabasetable.Aqueryoptimizertranslatesthedescriptionintoaproceduretoperformthedatabasemanipulation.

SQLwasoneofthefirstcommerciallanguagesforEdgarF.Codd’srelationalmodel,asdescribedinhisinfluential1970paper,“ARelationalModelofDataforLargeSharedDataBanks”.DespitenotadheringtotherelationalmodelasdescribedbyCodd,itbecamethemostwidelyuseddatabaselanguage.

RelationalDatabases

BeforelookingatSQLitselfit’sworthlookingmorecloselyatwhatismeantbyadatabase.AlthoughsomepeopletalkaboutSQLdatabases,thereisinfactnosuchthing.SQLitselfmakesnoreferencestotheunderlyingdatabaseswhichitcanaccess,whichmeansthatitispossibletohaveaSQLenginewhichcanaddressrelationaldatabases,non-relational(flat)databases,evenspreadsheets.However,SQLismostoftenusedtoaddressarelationaldatabase,whichiswhatsomepeoplerefertoasaSQLdatabase.

TherelationalmodelofadatabasewasfirstdefinedbyDrE.FCoddin1970,workingattheIBMResearchLabsatSanJose,anditdescribesawayofstructuringdatawhichismathematicallyconsistentandabstractedawayfromthephysicalimplementationofthedatabase.

Thekeyconceptoftherelationalmodelisthatdatasitsintables,andthatdataelementswithindifferenttablescanberelatedinsomewaytoprovidemeaningfulinformationratherthanjustlistsofdata.Eachtableinthedatabasehasanumberoffieldswhichdefinethecontentandanumberofinstancesofthatfield—thinkofthefieldsascolumnsinatableandtheinstancesasrows.ForexampleifwehadatableofLANusers,thenitmighthavefieldsoffirstname,surnameanduserID.Therowsinsuchatablewouldcontainthevalueswhichdefineeachinstanceofuser,forexampletheentrytodefineuserJohnSmithmightbe:John,Smith,JSmith.

AWordAboutDatatypes

Manykindsofdatacanbestoredinadatabase,fromsimpletexttovarioustypesofnumbertoBooleanflagstobinaryobjectsandgraphics.Thisisoneareawheretherearedifferencesbetweendifferentproducts.Notjustintheformatsofdatathatcanbestored,butalsoinhowtheseformatsarenamed.Booleanfields,forexample,arecalledYes/NofieldsinMicrosoftAccess,andBOOLEANinthelaterreleasesofMySQL.

CreatingaDatabase

SQLcommandsfollowanumberofbasicrules.SQLkeywordsarenotnormallycasesensitive,thoughinthispassageallcommands(SELECT,UPDATEetc.)areupper-cased.Variableandparameternamesaredisplayedhereaslower-case.New-linecharactersareignoredinSQL,soacommandmaybeallononelineorbrokenupacrossanumberoflinesforthesakeofclarity.ManyDBMSsystemsexpecttohaveSQLcommandsterminatedwithasemi-coloncharacter.Finally,althoughthereisaSQLstandard,actualimplementationsvarybyvendor/system,soifindoubtalwaysrefertothedocumentationthatcomeswithyourDBMS.1.SQL(a)Acollectionofdataarrangedforeaseandspeedofsearchandretrieval.Alsocalled

databank.

EXERCISES2.RelationalDatabase(b)StructuredQueryLanguage,adatabasecomputerlanguagedesignedformanagingdatainrelationaldatabasemanagementsystems.3.Boolean(c)Adatabaseinwhichrelationsbetweeninformationitemsareexplicitlyspecifiedasaccessibleattributes.4.Database

(d)Relationaldatabasemanagementsystems.5.RDBMS

(e)OforrelatingtoacombinatorialsystemdevisedbyGeorgeBoolethatcombinespropositionswiththelogicaloperatorsANDandORandIFTHENandEXCEPTandNOT..Ⅱ.ArethefollowingstatementsTrue(T)orFalse(F)?

1．()SQLiscasesensitive,soSELECTisdifferentfromselect.

2．()Aqueryoptimizertranslatesthedescriptionintoaproceduretoperformthedatabasemanipulation.

3．()

SQLitselfmakesnoreferencestotheunderlyingdatabaseswhichitcanaccess.

4．()SQLcanaccessandmanipulatedatainvariousdatabasesystems.

5．()Thesamedatastoredinthesameformatindifferentdatabasesystems.

6．()New-linecharactersareignoredinSQL.

7．()ManyDBMSsystemsexpecttohaveSQLcommandsendedwithaperiodcharacter.

8．()SQListhestandardlanguagefordatamanipulation,soitimplementedthesamewayonvariousDBMS.

9．()Eachtableinthedatabasehasanumberofrowsbutonlyonefield.

10．()Therowsinatablewouldcontainthevalueswhichdefineeachinstanceofanentityset.Ⅲ.TranslatethefollowingwordsandphrasesintoChinese.Ⅳ.TranslatethefollowingChinesestatementsintoEnglish.

1.数据库管理系统相当于用户、计算机操作系统和数据库之间的接口。

2.数据库是存储在一起的相关数据的集合。

3.多个用户可以同时共享数据库中的数据资源，即不同的用户可以同时读取数据库中的同一个数据。

4.在关系数据库中，对数据的操作几乎全部建立在一个或多个关系表格上。

5.SQL语言的功能包括查询、操作、定义和控制，是一个综合的、通用的关系数据库语言，同时又是一种高度非过程化的语言。

Ⅴ.Fillineachoftheblankswithoneofthefollowingwordsorphrases.

relationalclassifiedacollectionofaccordingtoaccessed

standarddistributedobject-orientedtypicallycatalogs

Adatabaseis

informationthatisorganizedsothatitcaneasilybe

,managed,andupdated.Inoneview,databasescanbeclassified

typesofcontent:bibliographic,full-text,numeric,andimages.

Incomputing,databasesaresometimes

accordingtotheirorganizationalapproach.Themostprevalentapproachisthe

database,atabulardatabaseinwhichdataisdefinedsothatitcanbereorganizedandaccessedinanumberofdifferentways.A

databaseisonethatcanbedispersedorreplicatedamongdifferentpointsinanetwork.An

programmingdatabaseisonethatiscongruentwiththedatadefinedinobjectclassesandsubclasses.

Computerdatabases

containaggregationsofdatarecordsorfiles,suchassalestransactions,product

andinventories,andcustomerprofiles.Typically,adatabasemanagerprovidesusersthecapabilitiesofcontrollingread/writeaccess,specifyingreportgeneration,andanalyzingusage.Databasesanddatabasemanagersareprevalentinlargemainframesystems,butarealsopresentinsmallerdistributedworkstationandmid-rangesystemssuchastheAS/400andonpersonalcomputers.SQL(StructuredQueryLanguage)isa

languageformakinginteractivequeriesfromandupdatingadatabasesuchasIBM’sDB2,Microsoft’sSQLServer,anddatabaseproductsfromOracle,Sybase,andComputerAssociates.DatabaseManagementSystemandDatabaseModelAdatabase(sometimesspelleddatabase)isalsocalledanelectronicdatabase,referringtoanycollectionofdataorinformationthatisspeciallyorganizedforrapidsearchandretrievalbyacomputer.Databasesarestructuredtofacilitatethestorage,retrieval,modification,anddeletionofdatainconjunctionwithvariousdata-processingoperations.Databasescanbestoredonmagneticdiskortape,opticaldisk,orsomeothersecondarystoragedevice.SUPPLEMENTARY

Adatabaseconsistsofafileorasetoffiles.Theinformationinthesefilesmaybebrokendownintorecords,eachofwhichconsistsofoneormorefields.Fieldsarethebasicunitsofdatastorage,andeachfieldtypicallycontainsinformationpertainingtooneaspectorattributeoftheentitydescribedbythedatabase.Usingkeywordsandvarioussortingcommands,userscanrapidlysearch,rearrange,group,andselectthefieldsinmanyrecordstoretrieveorcreatereportsonparticularaggregateofdata.

Complexdatarelationshipsandlinkagesmaybefoundinallbutthesimplestdatabases.Thesystemsoftwarepackagethathandlesthedifficulttasksassociatedwithcreating,accessing,andmaintainingdatabaserecordsiscalledadatabasemanagementsystem(DBMS).TheprogramsinaDBMSpackageestablishaninterfacebetweenthedatabaseitselfandtheusersofthedatabase.(Theseusersmaybeapplicationsprogrammers,managersandotherswithinformationneeds,andvariousOSprograms.)

ADBMScanorganize,process,andpresentselecteddataelementsformthedatabase.Thiscapabilityenablesdecisionmakerstosearch,probe,andquerydatabasecontentsinordertoextractanswerstononrecurringandunplannedquestionsthataren’tavailableinregularreports.Thesequestionsmightinitiallybevagueand/orpoorlydefined,butpeoplecan“browse”throughthedatabaseuntiltheyhavetheneededinformation.Inshort,theDBMSwill“manage”thestoreddataitemsandassembletheneededitemsfromthecommondatabaseinresponsetothequeriesofthosewhoaren’tprogrammers.

Adatabasemanagementsystem(DBMS)iscomposedofthreemajorparts:

(1)astoragesubsystemthatstoresandretrievesdatainfiles;

(2)amodelingandmanipulationsubsystemthatprovidesthemeanswithwhichtoorganizethedataandtoadd,delete,maintain,andupdatethedata;

(3)andaninterfacebetweentheDBMSanditsusers.

Severalmajortrendsareemergingthatenhancethevalueandusefulnessofdatabase

managementsystems：

(1)Managersrequiremoreup-to-datainformationtomakeeffectivedecision.

(2)Customersdemandincreasinglysophisticatedinformationservicesandmorecurrentinformationaboutthestatusoftheirorders,invoices,andaccounts.

(3)Usersfindthattheycandevelopcustomapplicationswithdatabasesystemsinafractionofthetimeittakestousetraditionalprogramminglanguages.

(4)Organizationsdiscoverthatinformationhasastrategicvalue;theyutilizetheirdatabasesystemstogainanedgeovertheircompetitors.

TheDatabaseModel

Adatabasemodeldescribesawaytostructureandmanipulatethedatainadatabase.Thestructuralpartofthemodelspecifieshowdatashouldberepresented(suchastree,tables,andsoon).Themanipulativepartofthemodelspecifiestheoperationwithwhichtoadd,delete,display,maintain,print,search,select,sortandupdatethedata.Thecommonlyclassificationofthedatabasemodel：HierarchicalModel

Thefirstdatabasemanagementsystemsusedahierarchicalmodel-thatis-theyarrangedrecordsintoatreestructure.Somerecordsarerootrecordsandallothershaveuniqueparentrecords.Thestructureofthetreeisdesignedtoreflecttheorderinwhichthedatawillbeusedthatis,therecordattherootofatreewillbeaccessedfirst,thenrecordsonelevelbelowtheroot,andsoon.

Thehierarchicalmodelwasdevelopedbecausehierarchicalrelationshipsarecommonlyfoundinbusinessapplications.Asyouhaveknown,anorganizationchartoftendescribesahierarchicalrelationship:topmanagementisatthehighestlevel,middlemanagementatlowerlevels,andoperationalemployeesatthelowestlevels.Notethatwithinastricthierarchy,eachlevelofmanagementmayhavemanyemployeesorlevelsofemployeesbeneathit,buteachemployeehasonlyonemanager.Hierarchicaldataarecharacterizedbythisone-to-manyrelationshipamongdata.

Inthehierarchicalapproach,eachrelationshipmustbeexplicitlydefinedwhenthedatabaseiscreated.Eachrecordinahierarchicaldatabasecancontainonlyonekeyfieldandonlyonerelationshipisallowedbetweenanytwofields.Thiscancreateaproblembecausedatadonotalwaysconformtosuchastricthierarchy.

RelationalModel

Amajorbreakthroughindatabaseresearchoccurredin1970whenE.F.Coddproposedafundamentallydifferentapproachtodatabasemanagementcalledrelationalmodel,whichusesatableasitsdatastructure.

Therelationaldatabaseisthemostwidelyuseddatabasestructure.Dataisorganizedintorelatedtables.Eachtableismadeupofrowscalledrecordsandcolumnscalledfields.Eachrecordcontainsfieldsofdataaboutsomespecificitem.Forexample,inatablecontaininginformationonemployees,arecordwouldcontainfieldsofdatasuchasaperson’slastname,firstname,andstreetaddress.

NetworkModel

Thenetworkmodelcreatesrelationshipsamongdatathroughalinkedliststructureinwhichsubordinaterecordscanbelinkedtomorethanoneparentrecord.Thisapproachcombinesrecordswithlinks,whicharecalledpointers.Thepointersareaddressesthatindicatethelocationofarecord.Withthenetworkapproach,asubordinaterecordcanbelinkedtoakeyrecordandatthesametimeitselfbeakeyrecordlinkedtoothersetsofsubordinaterecords.Thenetworkmodehistoricallyhashadaperformanceadvantageoverotherdatabasemodels.Today,suchperformancecharacteristicsareonlyimportantinhigh-volume,high-speedtransactionprocessingsuchasautomatictellermachinenetworksorairlinereservationsystem.

Bothhierarchicalandnetworkdatabasesareapplicationspecific.Ifanewapplicationisdeveloped,maintainingtheconsistencyofdatabasesindifferentapplicationscanbeverydifficult.Forexample,supposeanewpensionapplicationisdeveloped.Thedataarethesame,butanewdatabasemustbecreated.

ObjectModel

Thenewestapproachtodatabasemanagementusesanobjectmodel,inwhichrecordsarerepresentedbyentitiescalledobjectsthatcanbothstoredataandprovidemethodsorprocedurestoperformspecifictasks.

Thequerylanguageusedfortheobjectmodelisthesameobject-orientedprogramminglanguageusedtodevelopthedatabaseapplication.Thiscancreateproblemsbecausethereisnosimple,uniformquerylanguagesuchasSQL.Theobjectmodelisrelativelynew,andonlyafewexamplesofobject-orienteddatabaseexist.Ithasattractedattentionbecausedeveloperswhochooseanobject-orientedprogramminglanguagewantadatabasebasedonanobject-orientedmodel.1．酒店预订的方式酒店预订的方式通常有以下几种：●电话预订(Telephone)；●传真订房(FAX)；●国际互联网预订(Internet)；●信函订房(Mail)；●口头订房(Verbal)；●合同订房(Contract)，指酒店与旅行社或商务公司之通过签订订房合同，达到长期出租客房的目的。CONVERSATION

BookingHotels

预订酒店

2．酒店预订的种类

(1)临时预订(AdvanceReservation)：客人在即将抵达酒店前很短的时间内或在到达的当天联系订房。

(2)确认类预订(ConfirmedReservation)：酒店可以事先声明为客人保留客房至某一具体时间，过了规定时间，客人如未抵达酒店，也未与酒店联系，则酒店有权将客房出租给其他客人。

(3)保证类预订(GuaranteedReservation)：指客人保证前来住宿，否则将承担经济责任，因而酒店在任何情况下都应保证落实的预订。保证类预订又分为三种类型:

预付款担保；

信用卡担保；

合同担保。

3.预订渠道预订渠道通常有以下几种：

散客自订房，可以通过电话、互联网、传真等方式进行；

旅行社订房；

公司订房；

各种国内外会议组织订房；

分时度假(timeshare)组织订房；

国际订房网络组织订房；

其他组织订房。

4.国际酒店通行的几种收费方式

(1)欧洲式(EuropeanPlan,EP)：只包括房费而不包含任何餐费的收费方式，为世界上大多数酒店所采用。

(2)美国式(AmericanPlan,AP)：不但包括房费，而且还包括一日三餐的费用，因此又被称为“全费用计价方式”，多为远离城市的度假性酒店或团队客人所采用。

(3)修正美式(ModifiedAmericanPlan,MAP)：包括房费和早餐，除此而外，还包括一顿午餐或晚餐(二者任选其一)的费用。这种收费方式较适合于普通旅游客人。

(4)欧洲大陆式(ContinentalPlan,CP)：包括房费及欧陆式早餐(ContinentalBreakfast)。欧陆式早餐的主要内容包括冷冻果汁(OrangeJuice、GrapeJuice、PineappleJuiciest等)、烤面包(ServedwithButter&Jam)、咖啡或茶。

(5)百慕大式(BermudaPlan,BP)：包括房费及美式早餐(AmericanBreakfast)。美式早餐除了包含欧陆式早餐的内容以外，通常还包括鸡蛋(Fried、Scrambledup、Poached、Boiled)、火腿(Ham)、香肠(Sausage)或咸肉(Bacon)等。ExampleDialogue1

F:Hello,welcometoPriseStarHotel.HowmayIdoforyou?

M:Hi,yes,Ihaveareservation.Mysecretarycalledandbookedaroomacoupleofweeksago;thereservationshouldbeforadoublebed,nonesmokingroom.

F:Andwhatnameofreservationmadeunder?

M:ItshouldbeunderSteveJohnson.

F:Mmm,letmesee,itseemsthereisnoJohnsonlistedforaroomfortonight,isthereanyothernamethatyoureservationlistunder？

M:No,hereistheconfirmationnumber,wouldthathelp?Itis898007,Ihadtheroombookedwithavisacordcard.

F:Ah,yes,hereitis,youhaveastandarddoubleroom,nonsmokingonthe3rdfloor,Ijustneedtoseesomeidentificationandthecreditcardyoubookedtheroomwithifyoudon’tmind.

M:Sure,hereitis.Woulditbepossibletocheckoutandpaythebillinthemorning,also,whattimeisbreakfastserved?

F:Thereisacontinentalbreakfastbuffetfrom6:00amto10:00am,it’sinthelobby.

M:Thankyou!

F:You’rewelcome!Dialogue2

A:Hello,thisisQuanChengHotel,isthereanythingIcanhelpyou,sir?

B:Yes,I’dliketobookaroom.

A:Sure,wehavedifferenttypeofrooms,whichwouldyouliketochoose?

B:I’mnotverycertain;couldyougivemeabriefintroduction,please?

A:OK,ourhotelprovidesstandardsingleroomanddoubleroom;accordingly,wealsohavespecialtreatmentforVIP.

B:Thankyou,Iwanttoreserveasingleroomwhichisbetterlocatedbetween4thfloorto7thfloor.Well,IneedthepersonnelinyourhoteltoopenthewindowandcleantheroombeforeIarrivethere.IsthatOK?

A:OK,sir,Ialreadytakensomenotesaboutyourrequirements.Nowletmechecktheroomonmycomputer.Well,onestandardsingleroomin6thfloorandthenumberis0603,needcleanandopenthewindow,anythingelse?

B:Thanks,howmuchdoesitcost?

A:Thatis580RMB.

B:Don’tyourhotelhavediscount?

A:I’mterriblysorry,sir.Ifyouneedadiscount,youshouldbeourVIPandstayhereforatleast3days.

B:OK,that’salright!Practice

ImaginethatMaryistheFrontDeskoftheABCHotel,andJohnDeepisgoingtoreservearoomfrom2ndto4th,May.JohnDeepiscallingtoMary.PleasecompletethefollowingdialoguebetweenMaryandJohnwiththegivenpoints:

Greeteachother.

Describingtheneededroomthatshouldbeasuitewithanoceanview.

Talkingthediscountandofferendedyesterday.

Talkingaboutthebreakfastandthecheck-intime.Tips酒店预订常用语

1．RoomReservations.MayIhelpyou?房间预订，有什么能帮助您的吗？

2．I’dliketobookadoubleroomforTuesdaynextweek.下周二我想订一个双人房间。

3．What’sthepricedifference？两种房间的价格有什么不同？

4．Adoubleroomwithafrontviewis140dollarspernight，onewitharearviewis115dollarspernight．一间双人房朝阳面的每晚140美元，背阴面的每晚115美元。

5．IthinkI’lltaketheonewithafrontviewthen．我想我还是要阳面的吧。

6．Howlongwillyoubestaying？您打算住多久？

7．We’llbeleavingSundaymorning．我们将在星期天上午离开。

8．AndwelookforwardtoseeingyounextTuesday．我们盼望下周二见到您。

9．I’dliketobookasingleroomwithbathfromtheafternoonofOctober4tothemorningofOctober10．我想订一个带洗澡间的单人房间，10月4日下午到10月10日上午用。

10．Wedohaveasingleroomavailableforthosedates．我们确实有一个单间，在这段时间可以用。

11．Whatistherate，please？请问房费多少？

12．Thecurrentrateis$50pernight．现行房费是50美元一天。

13．Whatservicescomewiththat？这个价格包括哪些服务项目呢？

14．Thatsoundsnotbadatall．I’lltakeit．听起来还不错。这个房间我要了。

15．Bytheway，I’dlikeaquietroomawayfromthestreetiftheispossible．顺便说一下，如有可能我想要一个不临街的安静房间。

16．I’dliketoconfirmmyreservation.ThisisXXXfromHongKong.I’vereservedadoubleroomforJanuarysecond.我想确定我的订房结果。我是从香港来的XXX。我已经预订了一间供1月2日入住的双人房。

17．MayIordermybreakfastfortomorrowmorning?我可以预订明天早上的早餐吗?

18．Bytheway,youmighthavemythingssentuphere.顺便说一句，请您把我的东西搬到这儿来。

19．I’dliketocancelmyreservationandmakeanewreservation.我想取消我原来的预订，并作新的预订。

20．Thisisratherexpensive.Imusthaveacheaperone.Can’tyoushowmesomethinglessexpensive？这有点贵。我要一间比较便宜的。可否给我看些较廉价的房间?

21．Yes，wedohaveareservationforyou．对了，我们这儿是有您预订的房间。

22．WouldyoupleasefilloutthisformwhileIprepareyourkeycardforyou？

23．请您把这份表填好，我同时就给您开出入证，好吗？

24．WhatshouldIfillinunderROOMNUMBER？“房间号码”这一栏我该怎么填呢？

25．I’lltakealookatthehotel’sbookingsituation．我来查看一下本店房间的预订情况。

26．Thisisareceiptforpayinginadvance．Pleasekeepit．这是预付款收据，请收好。

1.Askyourclienttolistthedealpoints.Thiscanbeintheformofalist,outlineornarration.Doingthiswillhelptheclientfocusonthetermsoftheagreement.要求你的客户列出合同交易的要点，也可以说是合同的清单、目录或概述。这一招首先帮助你的客户弄清合同的重点所在。

WRITING

HowtoWriteBusinessContract

如何写商务合同

2.Engageyourclientin“whatif”scenarios.Agoodcontractwillanticipatemanypossiblefactualsituationsandexpresstheparties’understandingincasethosefactsarise.Talkingtoyourclientaboutthiswillgeneratemanyissuesyoumaynototherwiseconsider.让你的客户提供一些假设可能发生的情况。好的合同不仅能够预见到许多可能发生的情况，而且还能清楚地描述出发生这些情况后合同双方的立场。和客户聊这些情况将有助于你发现一些你可能没有考虑到的问题。

3.SearchyourofficecomputerortheInternetforasimilarform.Manytimesyoucanfindasimilarformonyourcomputer.Itmaybeoneyoupreparedforanotherclientoroneyounegotiatedwithanotherlawyer.Justremembertofindandreplacetheoldclient'sname.Startingwithanexistingformsavestimeandavoidstheerrorsoftyping.在办公室的电脑中或是在因特网上搜索类似的合同范本。通常你会在你的电脑上找到你想要的东西，这些类似的合同范本要么是你给其他客户准备的，要么是你和其他的律师共同协商起草的。使用这些旧合同可以为你节省时间和避免打印错误。

4.Don’tletyourclientsignaletterofintentwithoutthiswording.Sometimesclientsareanxioustosignsomethingtoshowgoodfaithbeforethecontractisprepared.Aproperlywordedletterofintentisusefulatsuchtimes.Justbesurethattheletterofintentclearlystatesthatitisnotacontract,butthatitismerelyanoutlineofpossibletermsfordiscussionpurposes.如果没有特别申明，不要让你的客户在意向书上签字。有时候，在合同未准备好之前，客户为了表示诚意，往往急于签署某些东西。当然，在这种情况下，如果客户急于签署的是有特别申明的意向书，这也是可以的，但一定要注明：本意向书并非合同，只是双方为了更好地沟通协商而拟定的对未来条款的概述。

5.Statethecorrectlegalnamesofthepartiesinthefirstparagraph.Asobviousasthisis,itisoneofthemostcommonproblemsincontracts.Forindividuals,includefullfirstandlastname,andmiddleinitialsifavailable,andotheridentifyinginformation,ifappropriate,suchasJr.,M.D.,etc.Forcorporations,checkwiththeSecretaryofStatewhereincorporated.在合同的第一段要写清楚双方的名称，这是个简单而又不得不引起重视的问题。如果是个人，要写清姓和名,中间有大写字母和其他身份信息的，也要注明，例如Jr.，M.D等；如果是公司，为避免弄错，写名称时可以到公司注册地的相应机构去核对一下。

6.Becarefulwhenusinglegaltermsfornicknames.Donotuse“Contractor”asanicknameunlessthatpartyislegallyacontractor.Donotuse“Agent”unlessyouintendforthatpartytobeanagent,andifyoudo,thenyoubetterspecifythescopeofauthorityandotheragencyissuestoavoidfuturedisagreements.使用法定术语作为双方当事人的别称时要小心。除非一方当事人在法定上就是承包人，否则不要将“承包人”作为其别称。同样，除非你想让一方当事人成为法定上的代理人，否则不要称其为“代理人”，如果坚持要用，最好明确一下代理范围并找到其他可以避免将来争执的方案。

7.Watchoutwhenusing“herein”.Does“whereverusedherein”meananywhereinthecontractoranywhereintheparagraph?Clarifythisambiguityifitmatters.使用术语“本文”(herein，也可译为“在这里”)时要当心。为了避免含糊不清，使用“本文”时最好特别申明一下“本文”是指整个合同，还是指其所在的某一段落。

8.Writenumbersasbothwordsandnumerals:ten(10).Thiswillreducethechanceforerrors.写数目时要汉字和阿拉伯数字并用，如拾(10)。这将减少一些不经意的错误。

9.Whenyouwrite“including”consideradding“butnotlimitedto.”Unlessyouintendthelisttobeall-inclusive,youhadbetterclarifyyourintentthatitismerelyanexample.如果你想用“包括”这个词，就要考虑在其后加上“但不限于……”的分句。除非你能够列出所有被包括的项，否则最好用“但不限于……”的分句，来说明你只是想举个例子。

10.Beconsistentinusingwords.Ifyourefertothesubjectmatterofasalescontractas“goods”usethattermthroughoutthecontract;donotalternatelycallthem“goods”and“items”.Maintainingconsistencyismoreimportantthanavoidingrepetition.Don’tworryaboutputtingthereadertosleep;worryabouttheopposinglawyerayearfromnowhuntingforambiguitiestogetyourcontractintocourt.用词一致。在一份销售合同中，如果你想用“货物”来指整个合同的标的物，就不要时而称它们为“货物”，时而又改称它们为“产品”。保持用词一致性比避免重复更加重要。不要担心这会让读者打瞌睡，你应该提防的是对方律师会因为含糊不清的合同而将你告上法庭。Example

houldeitherofthepartiestothecontractbepreventedfromexecutingthecontractbyforcemajeure,suchasearthquake,typhoon,flood,fire,warorotherunforeseenevents,andtheiroccurrenceandconsequencesareunpreventableandunavoidable,thepreventedpartyshallnotifytheotherpartybytelegramwithoutanydelay,andwithin15daysthereafterprovidedetailedinformationoftheeventsandavaliddocumentforevidenceissuedbytherelevantpublicnotaryorganizationexplainingthereasonofitsinabilitytoexecuteordelaytheexecutionofallorpartofthecontract.在合作期间，由于地震、台风、水灾、火灾、战争或其他不可预见并且对其发生和后果不能防止及避免的不可抗力事故，致使直接影响合同的履行或者不能按约定的条件履行时，遇有上述不可抗力的一方，应立即将事故情况电报通知对方，并应在15天内提供事故的详细情况及合同不能履行，或者部分不能履行，或者需要延期履行的理由的有效证明文件。此项证明文件应由事故发生地区的有权证明的机构出具。

ThiscontractissignedbytheauthorizedrepresentativesofbothpartiesonDec.9,1999.Aftersigningthecontract,bothpartiesshallapplytotheirrespectiveGovernmentAuthoritiesforratification.Thedateofratificationlastobtainedshallbetakenastheeffectivedateofthecontract.Bothpartiesshallexerttheirutmosteffortstoobtaintheratificationwithin60daysandshalladvisetheotherpartybytelexandthereaftersendaregisteredletterforconfirmation.

本合同由双方代表于1999年12月9日签订。合同签订后，由各方分别向本国政府当局申请批准，以最后一方的批准日期为本合同的生效日期，双方应力争在60天内获得批准，用电传通知对方，并用挂号信件确认。Practice确认函致：中外运-敦豪公司客户服务部我司已知悉此类特殊安排存在风险并且DHL无法就成功完成此类特殊安排作出承诺。现我司确认中外运敦豪公司对快件______________(请填写运单号码)进行如下特殊安排(请勾选以下服务类别选项)，并同意支付由此产生的运费、海关税费或其他附加费用。对于未成功操作的服务，DHL将不收取服务费。ABC有限公司Article18Miscellaneous

1.Thepenalty,compensations,storageexpensesandvariouseconomiclossesasspecifiedinthiscontractshallbepaidwithin______days