Map-Oriented Visual Language : MOL

Masahide Ohtomo and Hideto Ikeda

Information Pticessing Center, Hiroshima University l-l-89 Higashi-Senda, Naka, Hiroshima 7W JAPAN

Abstrm New technologies and instruments of computer are

widely used, and it is the time to make eflorts in shap- ing the wmputer world to the user’s world. One of the efforts is improvement of a programming language. In Me ama of databaae systems, some fourth generation lan- guages adopted visual representations in order to improve their user interfaces. These ore, however, not s&Cent for naive users because of poor capability for describing pmce- duml ptvgnxma ?nd dificulty of understanding. This paper proposed a new visual language named MOL, which can be used by non-progmmmers to develop application systems. The structure .of database is represented as a special dia- gram which is referred to a ‘map” in this paper. On the map, iherr an some information centers which manage a collection of data. These centers are connected by avenues, when the& arc certain Mationships betweek respective data of two injoenation centers. A progmm is represented as a trail of the map. In order to access data with MOL, a user orders a messenger to. tnaes avenues, visit information cen- ters, collect data, fir1 a reporting sheet with the data and bring b&k it. The collected da+ can be processed on a spnsid sheet. By using MOL, user interface can be im- pmved to be mom fiendly for non-pmgmmmers than the other fourth genemtion languages without loss of powerful cupability of pmceduml languages.

Keywords and key-phrases : visual language, fourth generation language, information retrieval language, user interface, end user computing

1. Introduction E.F. Codd and J. Martin pointed out the effedtive-

ness of the end user computing against the application backlog [5,6&j. Many fourth generation languages (4GLs)

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haa been developed to support end user computing [l2]. One of the important problems of 4GL la improvement cif the user interface. Visual representations are ef&ctive and promising approach to the problem. Wide use of work- s’tation with a bit-mapped display and a pointing device accelerates visualization of programming languages. An icon technique is spread over various fields because icons make easy to find what can be done in the system.

A. Makinouchi and B.D. Yoon [lo] claaaified 4GLa into three groupe from the view point of user interface. A ttiget of the first group, e.g., SNAP (11, Ski [Q], GUIDE 1151, QPE [3], ia to support in making of a query. A focus of the second group, VIEW [14], MINOS [4], GRAIN [2] and TIMBER [131, is to present data in a vi- sual way. An intention of the last group, e.g., LID 17) and ISIS [S], is to f&ill both targets at a time,

It is important to visualize various kinds of proces8es by some standardized and restricted ways. but in general, simplification of a visual language conflicts with variety of representable processes. Xnformation retrieval is a kind of process. Practically, it is important to develop a language because a retrieval program is frequently used by end ueera and is a typical process.

,

On the other hand, J. Martin claaeified a 4GL into a procedural type and a non-procedural type. A nbn- procedural language has a merit in eaaineae for develop- ment of applications by end users. However, all applica- tions, especially, complex once, cannot be described with it.

SNAP [l] represents the .structure of 8 datebaae as an entity-relationship diagram. A wer makes a graph with selection of entities and relation&& and apeclflcationa of retrieval conditions. Queries rire generated from the graph. The graph is a visual representation of a retrieval process. Since an entity and a relationship are al&r&t notivne, au end user feels not friendly in use of the language.

MOL is a new visual language based on a map. The map is composed of information centers which are con- ncctad lly avenues. Each information center manages a coltcction of data. When there is a certain relatiolwhip between rapective data of two information centers, the ceuters are connected by an avenue named after the rela-

fnternational Symposium on Database Systems for Advanced Applications

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Seoul, Korea, April, 1999

tionship. A user calls a messenger on the map and directs him to visit information centers and collect data. The mes- senger traces avenues in the map, collects the data, fills a spread sheet with the data and returns it to the aser. The user can mauipulate the data on the spread sheet. A trail is a map in which the footprints of the messenger are marked. A user can save the trail which can be used when he executes the same process. A reuse of a trail corre- sponds to an automatic execution of the retrieval, and so a trail is a retrieval program.

MOL represents data and relationships as a map in familiarly to end users. Navigation is visualized as be- haviour of a messenger. Such a representation helps a user in his intuitive understanding of a program. An interac- tive interface of MOL relieves an end user from tortures of describing a complex procedure.

MOL is implemented on a workstation with a bit- mapped display and a pointing device. MOL uses LUG.2 to access a remote database. LU6.2 established by OS1 is a remote access protocol for database systems. MOL generates a sequence of commands to access a database corresponding to each action of a messenger. Data which are transferred to a workstation from a database system are processed by operations of spread sheet such as calcu- lation, derivation and deletion.

Section 2 describes basic concepts of a map-oriented visual language MOL and Section 3 illustrates actious of MOL. Moreover animplementation of MOL is discussed in Section 4.

2. Basic Concepts d~Ik&3&. . . .

2.1 Map MOL visualizes struetnre of a database as a map.

A map is composed of information centers which are con- nected with avenues. An information center manages a collection of data, and has a name which shows a content of the data. When there is a certain relationship between respective data of two information centers, the centers are connected by an avenue. A map is drawn by a database ad- ministrator. Example of a map is shown in Figure 1. The map corresponds to an entity-relationship diagram shows in Figure 2. A building in the map shows an information center. In this example, CUSTOMER information center in Figure 1 corresponds to CUSTOMER entity in Figure 2. EMPLOYEE information center corresponds to three entities; SALESMAN, ACCOUNTANT and BUYER. It implies a possibility of one-to-N correspondence.

2.2 User A user of MOL makes a ‘direct&m for a messenger.

A direction is represented by a map, reporting sheets and security kkys. All information centera that the messenger should visit are marked.. Reporting sheets inelude the data items to be collected and conditions of retrievals. A user has an office. A user calls a messenger to hi8 office and gives a direction. The user receives a report from the mes- senger, check them, and modifies the direction. When the user gets final reports, he saves the map, security keys, result sheets and closes his office.

SALESMAN

ACCOUNTAN

Figure 2. Entity-Relationship Diagram of SALES Management System

2.3 Merrenger

--

A messenger ie B pereon who col- lects information under some direc- tions of a user. He visits some informa- tion centers, collects data, fills sheets with the data and return them to his host. Figure 4 shows an interior of, a user office and a messenger who has 8 sheet bag and 8 key bag. MOL repre- aenta a retrieval process as behaviour of a messenger OII 8 map.

2.4 xnfbrmation cieQter An information cchter m

8 cobz’tion of data. Itirch &kfbrma- tion center has the same functions.

Figure 3. EMPLOYEE Information Center

Each center contains a securilg control bos, recap- tion desks, a general information desk, a work desk, a mail boz and a printer. Figure 3 shows an in- terior of an information center. A privilege of a messenger is checked at a security control gate. En& reception desk corrcmponcls to some! entit,ics.

A messenger can get information of data managed in the center and how to use of the facilities from the general information desk. A work desk is used to verify and calcu- late the data. A mail box is used to send reporting sheets to and receive modified directiona from his host.

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diirded.by the User. The contents of a waste &&et‘ is permanently di5

posed when the U&er closes hll office.

2.6 Avenue An avenue connects some infor-

mation centers. Each avenue has a name which is corresponding to a rela- tionship of data, Passing of the mes- senger on a avemte joins data in two centers. For example, in Figure 1, SALES avezu~ connects SALES and Eh4PLOYl% information centers and joins two sets of data by two items, salesman-name and employee-name.

2.5 User Of&e

Interior of a user o&e is shown in T:~FPv- -!.

2.7 Reportii Sheet Aqvxtiag sheet is contained in

a directian~for a messenger from the user. A- mesn&nger fills a sheet with collected data and returns it to his host. Figure 5 shows a reporting sheet. The datri items. to be collected are noted in the first- row. In the second row, the conditions of retrievals are noted. An example in Figure 5 implies directions; %etrieve the sales data of BIG Co&d. or SMALL Co.,Ltd. in 1988 ycsr tid report the names of merchandise, p&e and names of sales- men.” The messbnger notes collected data in a sheet. Whenever there is a sheet on a work desk, a lser can process data by operations of spread $heet, such a~ calculation, deletion, derivation.

2.8 Security -T&KI~ Is a &urity control gate

in ekty ihlhsamrrtioa ceate!t to protect data from wrcv% acces~~. A messen- gerneedea~keytopaa6agate. A dattabaue aihninkttator gives keys with a map to users.

2.9 Trail A trail is a map in which

sume footprints of a messenger are There is a beet kx on a work d&. Tl1c trr,s i:; I~!~~cc~I. A u$~r,cau save and reuse a trail to collect data a container of mails from his ruessengcr. A KIWI- along the :;RIKX route. Figure 6 shows a trail. When the saves reporting sheets, maps and tr;lils ia n c~h%ct. r~ssergn,r ~W:C~VW :3 trail, he traces his footprints. A reuse When a user wants to ask a mcssc:~:~cr S(Jnwt.~iiIq+ t.!~? of a trail enrrcspczds to execution of a retrieval ptowss. user makes a direction and sc~nc! it tc: thr: mcssc:I- Thus. a tmii is a retrieval program in MOL. There are ger. A wade ha&et contains reporting sleets which :II’” bwo wqr 60 execilte a trail. One is an automatic ezec&on

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Figure 6. Trail

I Salesran :1989.d.5 IIll

I Cur-rent data:2849

DJ -

hccowtant:1989.4.1 culm?nt data: 751

figure 7. General Information

and the other ia a steptiae esecution. Under a stepwise ezecdion, a meqenger waits for a direction of his host in each information center. A ueer can terminate an action of hia messenger any time.

3. ACTfONS of MOL

3.1 Direction MOL starts from an user office. Figure 4 shows an

user office. A user makes a direction on his desk. As

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shown in Figure 5, a direction is to collect data of sales for BIG Co., Ltd. or SMALL Co.,Ltd. in 1988. After making the direction, the user calls a messenger and gives him the direction. The messenger puts some reporting sheets and security keys in a sheet bag and.a key bag respectively. He gets out of the user office with the bags.

2.2 Visiting At first, the messenger goes to SALES information

3.4 Getting information The messenger goes to a general

information desk and asks about sales data in 1988. Figure 7 shows a menu of information. He-selects data items fol- lowing the characters i.e. the renewal date, the number of data, and so on.

Figure 8. Reporting Sheet ,at SALES.lnformation

3.5 Reception of data The messenger takes out a re-

porting sheet from his sheet bag. A sheet shown in. Figure 8 was filled with sales data at SALES information cen- ter. He puts a sheet on a reception desk. Since he.comes out of SALES information center through SALES av- enue, data of EMPLOYEE are joined with name of salesman. As shown in Figure 9, a sheet which is filled with data of EMPLOYEE is returned to the messenger.

3.6 Verification and calculation The messenger puts a sheet.on’a

work desk to show collected data to his host. He can manipulate the data in the spread sheet.

+‘:ei:r: 9. i.;cpo;:lng SS,.c;[ 2: EMPLOYEE information Center

3.7 Printing In order to print collected data, messenger picks a

printer. Then the user gets the printed data.

3.8 Mailing

center. He obtains data satisfying the condition shown in Figure 5. He puts a sheet on a reception desk. Then the sheet is BIled with resultant data. He goes out from SALES information center, takes SALES avenue and visits EMPLOYEE information center. r 3.3 Permission

Figure 3 shows the interior of EMPLOYEE information center. The messenger shows a security key at en- trance -gate of EMPLOYEE informa- tion center. He is permitted to enter the center.

3.9 Save When the user gets all reports, he saves the sheets,

the security keys, the trails and the maps. He closes his office and MOL is terminated.

A mailing service is also applicable for sending rc- porting sheets and security keys to the user.

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Window Manager t .J

I I I-

Window -

I IT

3 curity

>ata

LU6.2

-+

f3 Data

Figure 10, Configuration of MOL

4. Implementation A con&ration of MOL is shown in Figure 10. MOL

is implemented based on three software tools, a window manager, a database access protocol [LU6.2) and a spread sheet. MC% is a pTogrsm to control the three t&s.

The window manager controls all windows used in MOL. A user specifies directions for a messenger in each window.. By the specification, MOL decides a window to be active, generates a sequence of commands to access a database or transforms a format of received data into an- other format which spread sheet software can read.

LU6.2 is a remote access protocol for database sys- tems. When a user requests to retrieve data, MOL gener- ates a sequence df commands of LU6*2. By using LU6.2, the commands are transferred to a database and the result are sent back to LU6.2. The resultant data are transformed into a spread sheet by MOL.

A spre& she&t is caned by a window of MOL. In .a window, a user can manipulate collected data by opera- tions of the spread sheet software.

By use of the three tools, we can implement MOL as a.104 program of B workstation.

5. Discussion In this paper, we proposed a map-oriented vi-

sual language MOL which is a procedural language for information retrievals. A structure of a database is represented as a map. A procedure is represented as actions of a messenger on a map. A map is

well familiar and easy to understand for naive users. A map is also g&d to represent navigations.

A user sometimes gives a messenger a wrong instruc- tion. Collected data are often so large beyond user’s ex- pectation. A user of MOL can see and process collected data any time even on a way of collection. An interactive interface of MOL enables a user to specify his requests step-by-step.

We use LU6.2 for remote database access &rind a spread sheet software for calculations and modifications. It is easy to implement MOL because the programs to be developed are only interfaces among LU6.2, a spread sheet software and a window manager.

A large map can be divided into some screens in MOL, Rut .&I$ one or two screeus are used because al- most practical applications of their database include up to. 30 entities.

References

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