外文翻譯 MySQL數(shù)據(jù)庫(kù)管理中心

1、外文原文Management Center of MySQLAuthors: Lauderdale, Joh nTsa ng, Da nny H. K.Baciu, GeorgeIssue Date: 2006Citatio n: P roceedi ngs of IEEE Visual 96, Melbourne, Australia, February 2006, p. 447-458Database (sometimes sp elled database) is also called an electr onic database, referri ng to any collect

2、i ons of data, or in formati on, that is sp ecially orga ni zed for rap id search and retrieval by a computer. Databases are structured to facilitate the storage, retrieval, modificati on and deleti on of data in conjunction with various data-p rocess ing op eratio ns. Database can be stored on magn

3、 etic disk or tape, op tical disk, or some other sec on dary storage device.A database con sists of a file or a set of files. The in formatio n in the these files may be broke n dow n into records, each of which con sists of one or more fields are the basic un its of data storage, and each field typ

4、i cally contains in formatio n p erta ining to one aspect or attribute of the en tity described by the database. Using keywords and various sorting comma nds, users can rap idly search, rearra nge, group, and select the fields in many records to retrieve or create rep orts on p articular aggregates

5、of data.Database records and files must be orga ni zed to allow retrieval of the in formatio n. Early system were arran ged seque ntially (i.e., alp habetically, nu merically, or chro nologically); the development of direct-access storage devices made possible random access to data via in dexes. Que

6、ries are the main way users retrieve databasei nformatio n. Typ ically the user pro vides a stri ng of characters, and the compu ter searches the database for a corres ponding seque nee and pro vides the source materials in which those characters app ear. A user can request, for example, all records

7、 in which the content of the field for a person s last name is the word Smith.In flat databases, records are orga ni zed accordi ng to a simple list of en tities; many simple databases for personal compu ters are flat in structure. The records in hierarchical databases are organized in a treelike st

8、ructure, with each level of records branching off into a set of smaller categories. Un like hierarchical databases, which p rovide sin gle links betwee n sets of records at differe nt levels, n etwork databases create multi pie lin kages betwee n sets by placing links, or pointers, to one set of rec

9、ords in another; the speed and versatility of network databases have led to their wide use in bus in ess. Relati onal databases are used where associati ons among files or records cannot be exp ressed by lin ks; a simple flat list becomes one table, or “relation and,multiple relations can be mathema

10、tically associated to yield desired information. Object-oriented databases store and manipulate more complex data structures, called “ objects which are organized into hierarchical classes that may inherit properties from classeshigher in the chain; this databasestructure is the most flexible and ad

11、a ptable.The information in many databasesconsists of natural-language texts of documents; Small databases can be used by in dividuals at home. These and larger databases have become in creas in gly imp orta nt in bus in ess life. Typ ical commercial app licati ons in clude airli ne reservations, pr

12、oduction management, medical records in hospitals, and legal records of in sura nee compani es. The largest databases are usually main tai ned by gover nmen tal age ncies, bus in ess orga ni zatio ns, and uni versities. These databases may contain texts of such materials as catalogs of various kin d

13、s. Refere nee databases contain bibliogra phies or in dexes that serve as guides to the locati on of in formati on in books, p eriodicals, and other p ublished literature. Thousa nds of these p ublicly accessible databases now exist, coveri ng top ics ranging from law, medic ine, and engin eeri ng t

14、o n ews and curre nt eve nts, games, classified advertiseme nts, and in structi onal courses. Professi on als such as scie ntists, doctors, lawyers, finan cial an alysts, stockbrokers, and researchersof all types increasingly rely on these databasesfor quick, selective access to large volumes of in

15、formatio n.DBMS Structuring TechniquesSequential, direct, and other file processing approaches are used to organize and structure data in sin gle files. But a DBMS is able to in tegrate data eleme nts from several files to an swer sp ecific user inq uiries for in formati on. That is, the DBMS is abl

16、e to structure and tie together the logically related data from several large files.Logical Structures. Identifying these logical relationships is a job of the data administrator. A data definition Ianguage is used for this purpose. The DBMS may then employ one of the following logical structuring t

17、echniques during storage, access, and retrieval op erati ons.List structures. In this logical app roach, records are lin ked together by the use of poin ters. A poin ter is a data item in one record that ide ntifies the storage locati on of ano ther logically related record. Records in a customer ma

18、ster file, for example, will contain the name and address of each customer, and each record in this file is identified by an account number. During an acco un ti ng p eriod, a customer may buy a nu mber of items on differe nt days. Thus, the company may mai nta in an inv oice file to reflect these t

19、ran sacti ons. A list structure could be used in this situati on to show the unp aid inv oices at any give n time. Each record in the customer in the invoice file includes a field, it pointed to the location of the first invoicerecord in invoice file, this invoice record, in turn, would be linked to

20、 next invoices for the customer. The last inv oice in the cha in would be ide ntified by the use of a sp ecial character as a poin ter.Hierarchical (tree) structures. In this logical approach, data units are structured inmult ip le levels that grap hically resemble an“ up side dow n ” tree with the

21、root at the top athe bran ches fomed below. There s a superibord in ate relati on shi p in a hierarchical (tree) structure. Below the sin gle-root data component are subordi nate eleme nts or no des, in turn, each element or branch in this structure below the root has only a single owner. Thus, a cu

22、stomer owns an inv oice, and the inv oice has subord in ate items. The bran ches in a tree structure are not conn ected.Network Structures. Uni ike the tree app roach, which does not p ermit the conn ecti on of bran ches, the n etwork structure p ermits the conn ecti on of the no des in a multidirec

23、ti onal manner. Thus, each node may have several owners and may, in turn, own any nu mber of other data un its. Data man ageme nt software p ermits the extracti on of the n eeded in formatio n from such a structure by beg inning with any record in a file.Relational structures. A relational structure

24、 is made up of many tables. The data are stored in the form of relations” in these tablesThis is a relatively new database structuring approach that s expected to be widely implementbel future.Physical Structures. People visualize or structure data in logical ways for their own purp oses. Thus, reco

25、rds R1 and R2 may always be logically lin ked and p rocessed in seque nee in one particular application. However, in a computer system it quite possible that these records that are logically contiguous in one application are not physically stored together. Rather, the p hysical structure of the reco

26、rds in media and hardware may depend not on ly on the I/O and storage devices and storage tech niq ues used, but also on the differe nt logical relati onships that users may assig n to the data found in R1 and R2. For exa mple, R1 and R2 may be records of credit customers who have shi pmen ts send t

27、o the same block in the same city every 2 weeks. From theshipping department manager s perspective, then, R1 and R2 are seque ntial en tries on a geogra phically orga ni zed shipping rep ort. But in the A/R app licati on, the customers represented by R1 and R2 may be identified, and their accounts m

28、ay be p rocessed, accordi ng to their acco unt nu mbers which are widely sep arated. In short, the n, the physical location of the stored records in many computer-based information systems is in visible to users.ve dividedDatabase Management Features of MySQLMySQL in eludes many features that make t

29、he database easier to man age. We the discussi on in this sect ion into three categories: MySQL Enterp rise Man ager, add-on p acks, back up and recovery.1. MySQL Enterprise ManagerAs part of Database Server, MySQL p rovides the MySQL En terprise Man ager (EM), a databasema nageme nt tool framework

30、with a grap hical in terface used to man age database users, in sta nces, and features (such as rep licati on) that can pro vide additi onal in formati on about the MySQL en vir onment.Prior to the MySQL 8i database, the EM software had to be in stalled on Win dows 95/98or NT-based systems and each

31、repository could be accessed by only a single database man ager at a time. Now you can use EM from a browser or load it onto Win dows 95/98/2000 or NT-based systems.Multipie database administrators can accessthe EM repository at the same time. In the EM repository for MySQL9i, the super administrato

32、r can define services that should be dis played on other adm ini strators con soles, and man ageme nt regi ons can bset up.2. Add-on p acksSeveral optional add-on packs are available for MySQL, as described in the followingsecti ons. In additi on to these database-ma nageme npacks, man ageme ntp ack

33、s are available for MySQL AppI icatio ns and for SAP R/3.(1) standard Management PackThe Sta ndard Man ageme nt P ack for MySQL pro vides tools for the man ageme nt of smallMySQL databases (e.g., MySQL Server/Standard Edition). Features include support forp erforma nee mon itori ng of database conte

34、n ti on, I/O, load, memory use and in sta nee, sessi onan alysis, in dex tuning, and cha nge inv estigati on and track ing.(2) Diagnostics PackYou can use the Diag no stic P ack to mon itor, diag no se, and maintain the health of Enterp rise Editi on databases, op erati ng systems, and app licati on

35、s. With both historical and real-time analysis, it can automatically avoid problems before they occur. The pack also provides capacity planning features that help you plan and track future system-resource requireme nts.(3) Tuning PackWith the Tuning P ack, you can op timise system p erforma nee by i

36、de ntify ing and tuningEnterp rise Editi on databases and app licati on bottle necks such as in efficie nt SQL, poor data desig n, and the improper use of system resources. The p ack can p roactively discover tuning opportun ities and automatically gen erate the an alysis and required cha nges to tu

37、ne the systems.(4) Change Management PackThe Change Management Pack helps eliminate errors and avoid loss of data when up grad ing Enterp rise Editi on databasesto support new app licatio ns. It can an alysis impact and comp lex dependen ciesassociatedwith app licatio n cha nges and automatically p

38、erform databaseu pgrades. Users can use the easy-to-use wizards that teach the systematic ste ps n ecessary to up grade.(5) AvailabilityMySQL Enterprise Manager can be used for managing MySQL Standard Edition or Enterprise Edition. To Enterprise Edition, additional functionality is provided by separ

39、ate Diag no stics, Tuning, and Change Man ageme nt P acks.3. Back up and RecoveryAs every database adm ini strator kno ws, back ing up a database is a rather mundane but n ecessary task. An improper back up makes recovery difficult, if not imp ossible. Unfortun ately, people ofte n realize the extre

40、me imp orta nee of this everyday task only whe n it is too late -usually after losi ng bus in ess-critical data due to a failure of a related system.The follow ing secti ons describe some p roducts and tech niq ues for p erform ing database back up op erati ons.(1) Recovery ManagerTyp ical back ups

41、in clude compi ete database back ups (the most com mon typ e), database back ups, con trol file back ups. P reviously, MySQL sEnterp rise Back up Utility (EBU) pro vided a similar soluti on on some p latforms. However, RMAN, with its Recovery Catalog stored in an MySQL database, provides a much more

42、 complete solution. RMAN can automatically locate, back up, restore, and recover databases, con trol files, and archived redo logs. RMAN for MySQL9i can restart back ups and restores and imp leme nt recovery win dow p olicies whe n back ups exp ire. The MySQL Enterp rise Man ager Back up Man ager pr

43、o vides a GUI-based in terface to RMAN.(2) In creme ntal back up and recoveryRMAN can p erform in creme ntal back ups of Enterp rise Editi on databases Jn creme ntal back ups back up only the blocks modified since the last back up of a datafile, tables pace, or database;thus, they smaller and faster

44、 tha n comp lete back ups. RMAN can also p erform point-in-time recovery, which allows the recovery of data until just prior to a undesirable eve nt.(3) Legato Storage ManagerVarious media-ma nageme nt software ven dors support RMAN. MySQL bun dles Legato Storage Man ager with MySQL to p rovide medi

45、a-ma nageme nt services, in cludi ng the track ing of tape volumes, for up to four devices. RMAN in terfaces automatically with the media-ma nageme ntsoftware to request the moun ti ng of tapes as n eeded for back up and recovery op erati ons. AvailabilityWhile basic recovery facilities are availabl

46、e for both MySQL Standard Edition and Enterp rise Editi on, in creme ntal back ups have typi cally bee n limited to Enterp rise Editi on. Choosing between MySQL and SQL ServerI have to decide between using the MySQL database and its development system, Microsoft SQL Server with Visual Studio. This c

47、hoice will guide our future Web projects. What are the strong points of each of these comb in atio ns and what are the n egatives?Lori: Making your decisi on will depend on what you already have. For in sta nee, if you want to imp leme nt a Web-based database app licati on and you are a Win dows-on

48、ly shop, SQL Server and the Visual Studio p ackage would be fine. But the MySQL soluti on would be better with mixed p latforms.There are other things to consider, such as what extras you get and what skills are required. WebDB is a content man ageme nt and devel opment tool that can be used by cont

49、ent creators, database administrators, and developers without any programming experienee. WebDB is a browser-based tool that helps ease content creati on and pro vides mon itori ng and maintenance tools. This is a good soluti on for orga ni zatio ns already using MySQL. MySQL also scales better than

50、 SQL Server, but you will need to have a competent MySQL adm ini strator on hand.The SQL Sever/Visual Studio approach is more difficult to use and requires an exp erie need object-orie nted p rogrammer or some exte nsive trai ning. However, you do get a fistful of development tools with Visual Studi

51、o: Visual Basic, Visual C+, and Visual In terDev for o niy $1,619. P lus, you will have to add the cost of the SQL Server, which will run you $1,999 for 10 clients or $3,999 for 25 clients-a less expensive solution than MySQL s.MySQL also has a package solution that starts at $6,767, depending on th

52、e platform selected. The MySQL.com suite in cludes n ot o nIy WebDB and MySQL 8i but also other tools for devel opment such as the MySQL app licati on server, JDevel oper, and Work place Tempi ates, and the suite runs on more p latforms tha n the Microsoft soluti on does. This can be a good soluti o

53、n if you are a start- up or a small to midsize bus in ess. Buying these tools in a p ackage is less costly tha n pu rchas ing them in dividually.Much depends on your skill level, hardware resources, and budget. I hope this helps in your decisi on-mak ing.Brooks: I totally agree that this decisi on d

54、epends in large part on what in frastructure ands going to beexp ertise you already have. If the decisi on is hard, you n eed to figure out who doing the work and what your p riorities are.These two p roducts have differe nt app roaches, and they reflect the differe nt person alities of the two ven

55、dors. In gen eral, MySQL p roducts are desig ned for very pro fessi onal devel opment efforts by top-no tch p rogrammers and p roject leaders. The lear ning p eriod is fairly long, and the soluti on is p ricey; but if you stick it out you will ultimately have greater scalability and greater reliabil

56、ity.If your project has tight deadlinesand you don t have the timr money to hire a team of very expen sive, very exp erie need devel op ers, you may find that the MySQL soluti on is an easy way to get yourself in trouble. There s nothing worse than a poorMySQelopedapp licati on.What Microsoft offers

57、 is a soluti on that aimed at rap id devel opment and low-cost impiementation. The tools are cheaper, the servers you llrun it on are cheaper, and the devel opers you n eed will be chea per. Choos ing SQL Sever and Visual Studio is an excelle nt way to start fast.Of course, there are trade-offs. The

58、 key problem I have with Visual Studio and SQL Server is that you lbe tied to Microsoft op erati ng systems and In tel hardware. If the day comes when you need to support hundreds of thousands of users, you really don have any where to go other tha n buying hun dreds of servers, which is a man ageme

59、 nt ni ghtmare.If you go with the Microsoft app roach, it sounds like you may not n eed more tha n Visual Interdev. If you already know that you rgoing to be developing ActiveX components Visual Basic or Visual C+, t hat s warning sign that maybe you should look at thMySQL soluti on more closely.14中文譯文MySQL數(shù)據(jù)庫(kù)管理中心數(shù)據(jù)庫(kù)（有時(shí)拼成database也稱(chēng)為電子數(shù)據(jù)庫(kù)，是指由計(jì)算機(jī)特別組織的快速查 找和檢索的任意的數(shù)據(jù)或信息集合。數(shù)據(jù)庫(kù)與其它數(shù)據(jù)處理操作協(xié)同工作，其結(jié)