SAR Journal. Volume 2, Issue 1, Pages 39-46, ISSN 2619-9955, DOI: 10.18421/SAR21-06 March 2019.

Application of ORACLE Database Design in the Creation of Information Systems for Small and Medium Enterprises

Fadil Novalić, Hamza Kamberović, Muzafer Saračević

University of Novi Pazar, D. Tucovića bb, Novi Pazar,

Abstract – This paper describes the importance of the The access to the creation and the use of development of information systems for the needs of information systems should be comprehensive. In small and medium enterprises. The paper refers to order to successfully create and implement the other researches which prove the necessity of system, the starting point is modeling the actual introducing information systems in small and medium system. For this task are used some of the modeling enterprises. Oracle Database Design is presented as a simple and efficient manner to create a database on the tools in order to encompass all the necessary system grounds of which the information system has been entities and the relationships among them, while successfully developed. This paper provides a complete avoiding inclusion of unnecessary data, duplication example of database design. The conclusion provides a of data, placement of data in a place that is not the proposal for further researches that can be based on best for it, and similar defects in modeling. this paper. The course of work is determined by the flows in the development and application of information Keywords – Oracle, Information system, ERD, Database. systems in small and medium enterprises. Therefore, it is possible to say that the subject of this research is problem analysis of the businesses of small and 1. Introduction medium enterprises caused by the lack of use of

In the era of accelerated development of information systems in the business, presentation of information and communication technologies and the tools for modeling the real system, and a their applications in many spheres of everyday life, description of an actual example of a system information systems have become a business's developed according to Oracle rules for modeling helping tool in almost every small and medium-sized real system and database design. enterprise. For the purposes of this paper was used the research on the importance of using Web application as a kind of information system in small and medium-sized enterprises. [1] The aim of the paper is to present the rules for efficient modeling of the real system according to the DOI: 10.18421/SAR21-06 requirements and for the needs of a particular https://dx.doi.org/10.18421/SAR21-06 company’s business. The realization of the Corresponding author: Fadil Novalić, mentioned goal of the paper should result with a University of Novi Pazar, D. Tucovida bb, Novi Pazar, good solution in creating a quality model of the real Serbia system which presents a small enterprise. Email: [email protected] The paper deals with modeling of the real system according to Oracle database design principles. Received: 22 January 2019. These rules manage to successfully bring designers Accepted: 05 March 2019. Published: 25 March 2019. to complete solutions, which sometimes may be complex. It starts from modeling the real system, © 2019 Fadil Novalić, Hamza Kamberović, which gives the conceptual model of the system. Muzafer Saračević; published by UIKTEN. This work is System entities are treated as entities, their licensed under the Creative Commons Attribution- characteristics, essential for the functioning of the NonCommercial-NoDerivs 3.0 License. system, represent the attributes of the entities, and

The article is published with Open Access at relationships between them are related. Of course, www.sarjournal.com during all of this are taught the rules about optimal data structure, in order to keep data within the

SAR Journal – Volume 2 / Number 1 / 2019. 39 SAR Journal. Volume 2, Issue 1, Pages 39-46, ISSN 2619-9955, DOI: 10.18421/SAR21-06 March 2019. structure running at the best location, avoiding "Objects-links diagram (ERD) is a graphical unnecessary duplication of data, etc. These rules are presentation of the associated entities and constraints defined through three forms of normalization. The that constitute the given design or project. As with conceptual model of the system is represented other visually-oriented design methodologies, it through the Entity Relationship Diagram - ERD, in provides a graphical summary of the database which the elements are represented by a standard, so structure that is very useful to the designer. "[5] that anyone who knows the standards of creating Based on the above, we realize that the ERD is these diagrams can understand them. After the based on important participants in the system conceptual model, the next step is moved to creating (entities), their features (attributes) and relationships a physical database, again according to the well- (relations). Of course, creating a conceptual data defined rules according to which the entities become model is not that simple. It is necessary to include in tables, the attributes become columns, and the links it all the necessary details. serve to define foreign keys by which tables are An entity is an object in a system, an event, or a interconnected.. concept. According to the Oracle database design rules, the entity name consists of a noun singular and 2. Oracle database design printed in capital letters. For example, CAR, ACCOUNT, CARPART, etc. Data describing the The design of database represents an interphase in entity are its attributes. The attribute is a specific designing the information system. In order for the piece of information that: describes an entity, information system to support the real-world quantifies an entity, qualifies an entity, classifies an functions of the system, it should make its image entity, and / or specifies an entity. Attributes have understandable for information technology. In other their own data type. They can represent a number, a words, the information system is a model of the real string of characters, a date, a file, and so on. For system. Through the process of developing the example, for an entity CARPART, the attributes can information system, real-world model systems are be a code, a name, a category, a date of production, a created on several levels. The first model obtained is price, etc. Instance is the notion that must be called a logical or conceptual model, and the mentioned in the story about the entities. It represents following one is a physical model, which implies a one copy of the entity. Each instance is uniquely database. The starting point in modeling the identified by one attribute or a combination of information system is to comprehend the real system multiple attributes. This attribute or combination of as a set of elements interacting with one another. attributes is called a Unique Identifier(s)-UID. The "The system is most generally defined as a set of UID has a different value for each instance, while objects (entities) and their interconnections. Objects other attributes can have the same value in multiple in the system can be some physical objects, concepts, instances, but only one value for one instance at one events, and more. Objects in a model of a system are time. For example, the instance CARPART can be a described through their properties (attributes) and set battery. It may have its own UID in the form of an relationships that connect these objects, as well as the article code and this code can not be assigned to any characteristic of those relations."[6] other car part. The attribute price may have the same uses the model of entity value for multiple car parts, but each car part can relations represented through a diagram when have only one price at a time. modeling the information systems. "Model of Entity Sometimes it makes sense to divide the entity into Relations (ER Model) is a list of all entities and subtypes. This can be the case when a group of attributes, as well as all relationships between entities instances has special properties, such as attributes that are of significance. This model also provides and connections that exist only for this group of basic information such as entity names, data types, instances. In this case, the entity is called an entity's and constraints. This model does not necessarily overhead, and each group is called an entity subtype. include an image, but usually the model presented For example, in car service, the entity SERVICE can through a diagram is very valuable."[4] be related to the sale of car parts and to the car's Oracle's conceptual model is called Entity service itself. These subjects in the car service Relationship Diagram - ERD. "The entities-links business have common attributes, but car parts must diagram, known as ERD, is a consistent tool that can have a price, while the price of the service itself will be used to represent the needs for data regardless of be based on the price of a working hour. which database type is used and even when the Oracle has set conventions on the presentation of database is not used at all." [2] the ERD elements. This allows a proper The ERD can also be called a data model, since it interpretation of the conceptual model of the system is the starting model of the information system. by the database designer. According to the above conventions, the entity and its attributes are placed in

40 SAR Journal – Volume 2 / Number 1 / 2019. SAR Journal. Volume 2, Issue 1, Pages 39-46, ISSN 2619-9955, DOI: 10.18421/SAR21-06 March 2019. an oval box. An entity is named in singular and 3. An example of a car service system modeling printed in capital letters. Attributes are marked with one or more words that represent their meaning. As an example we have taken an actual car service. They are written in lowercase. In front of the After analyzing the car service business through a attribute, the label is #: for UID, * for mandatory conversation with the company management, we attributes and o for optional ones. have received the following scenario for modeling Relations between entities determine the entity's the system: mutual relationship based on two criteria: cardinality "The service sells car parts and their installation and optionality. Cardinality determines whether each and other services that do not require car parts sale. instance of the first entity is associated with one or There is no car sale without car servicing. Each time more instances of another entity, and the optionality a car comes to service, a new order is opened. The of whether each instance of the first entity must or order records the date of servicing, the current must not but may be related to the instances of mileage of the car, the price of a working hour, the another entity. For example, each REPAIR must separate rebate amount both for the parts and the include one and only one SERVICE, while each service. The rebate amount will be suggested by the SERVICE may or may not be executed in one or information system based on a specific algorithm more REPAIR. Based on the cardinality, the relations defined by the service management. It must be can be: one to one (1:1), one to more (1:M) and more known who of the employees of the service has to more (M:M). In terms of optionality, relations opened the account and whether a bill is issued for might be mandatory and optional. The relation can be that order. The order includes any repairs made on mandatory at one end and optional on the other. the car during one visit to the service. The repair There are barred relations, too. These relate to the includes the sale and installation of car parts or the inclusion of foreign keys in the UID, which is then provision of a service that does not require called a complex unique identifier. For example, installation of a car part. It is described by code, the each repair can be uniquely identified by means of number of car parts installed, the current car part unit the code assigned to it, but also via a complex key price, and the time of operation. The amount for the that includes the UID of the car, the UID of the built-in car part is determined based on its current service and the date of the repair. price and quantity, and for the performed repair Drawing relations in the ERD is subject to based on the work period and the price of the conventions. Mandatory relations are drawn in full working hours taken from the order. It is not line, and the optional ones are dashed. The relation is necessary to record the serial number of the included at the end "one" indicated by a single line, and at the car part. end "more" with three lines that are assembled into In the order, the amounts without rebates for parts one at the other end of the connection. The barred and services are calculated on the basis of the value relation is indicated by a vertical line at the end of of the repairs, while the other necessary values of the the link where the complex UID is formed. amount will be calculated on the basis of the amount Based on the conceptual model of the system, a without rebates and the actual amount of the rebates. relation database is created that represents the These are the amounts for parts, for services and in physical model of the system. Oracle Corporation total, and the amounts of rebates and the amounts for calls this process the translation of the ERD. There is payment. also a change in terminology, which is called The management's request is to present an amount mapping of terms with which the basic elements of without rebates for each order, the amount of the the ERD are named. The following is the term rebates and the amount to be paid. It must also have mapping scheme: the ability to review reports on the total turnover and debts of the vehicle owner. The report should include Conceptual model Physical model amounts from all orders opened for all vehicles Entity Table owned by that customer. Instance Row For the service are important the data code and Attribute Column name, and for car part even the price. Relation Foreign Key

Figure 1. Term mapping scheme

SAR Journal – Volume 2 / Number 1 / 2019. 41 SAR Journal. Volume 2, Issue 1, Pages 39-46, ISSN 2619-9955, DOI: 10.18421/SAR21-06 March 2019.

The invoice contains the number of the account, For the customer, it is necessary to know the the date of issuance and the VAT rate, indications Personal Identification Number, surname, name, whether the account was issued to the customer and address, city, mobile phone number, and may also whether it was paid, the surname and the name of the have information about the home phone number, employee who billed the account and the surname work phone number and the email address. and the name of the person who took the bill. It does The company is described by the name, address, not have to be the owner of the car, it can be city, land-line and mobile phone, the fax number and someone else who takes the bill on behalf of the the manager. The company can be expanded to owner. In addition to these data, the bill takes over multiple facilities that can be located in different from the order: the number of the order, the surname locations, even in several cities. " and name of the vehicle owner, the price of a On the basis of the scenario, the following entities working hour, the amount of rebates for parts and are identified: EMPLOYEE, COMPANY, services and all calculated amounts. CUSTOMER, VEHICLE, SERVICE, PART, The employee’s Personal Identification Number REPAIR, ORDER AND ACCOUNT. The service must be known, his surname, name and the mobile entity is overheaded, and PART is a subtype. These phone number, and it might have information about entities, with attributes and relations, will be the address and city of residence, the number of the presented in the following entity-relations diagram home phone and the email address. (ERD): The vehicle should contain information about the owner, brand, model, registration plate number, chassis number, engine number and year of production, and the type of the fuel may also be recorded.

42 SAR Journal – Volume 2 / Number 1 / 2019. SAR Journal. Volume 2, Issue 1, Pages 39-46, ISSN 2619-9955, DOI: 10.18421/SAR21-06 March 2019.

CITY CUSTOMER EMPLOYEE gives incoming # postal code # code * name of the city # code * PIN gives incoming * PIN * surname owns * surname * name finds * name * address * mobile phone * mobile phone COMPANY o address o home phone has o home phone o work phone # code o email address manages o email address * name * address owns * phone number open issues * fax number o mobile number belongs BRAND belongs VEHICLE belongs MODEL # code has # code has # code * name * registration * name * chasis number * engine number uses * make year FUEL is used # code * name has

REPAIR SERVICE contains # code # code * parts quantity consists * name * parts price * time of work PART * price belongs

contains

ORDER # number * order date open open * mileage * working hour price forms BILL * parts rabate * service rabate formed # number * bill date * VAT rate issued * issued * paid * bill received

Figure 2. The conceptual model of the car service system presented through the ERD

Based on the ERD shown, a physical model of the about the services and auto parts separately, we have car service system has been created. Due to the mapped the overheaded and the subtype by "two-tab requirement of a service manager to keep the data implementation".

SAR Journal – Volume 2 / Number 1 / 2019. 43 SAR Journal. Volume 2, Issue 1, Pages 39-46, ISSN 2619-9955, DOI: 10.18421/SAR21-06 March 2019.

Table 1. Scheme of the physical model of the car service EMPLOYEES (EMPLS) system Key type Optionality Column name BRANDS (BRNS) pk * code Key type Optionality Column name uk * PIN pk * code * surname * name * name

* phone_mobile MODELS (MDLS) o address Key type Optionality Column name o phone_fix pk * code o email * name fk o post_no_city uk * code_brands

COMPANIES (CMNS) FUELS (FLS) Key type Optionality Column name Key type Optionality Column name pk * code pk * code * name * name * address * phone_fix CITIES (CTS) * fax Key type Optionality Column name o phone_mobile pk * post_no fk * code_manager * name_city fk * post_no_city

SERVICES (SRCS) PARTS (PTS) Key type Optionality Column name Key type Optionality Column name pk * code pk * code * name * name

* price CUSTOMERS (CMRS)

Key type Optionality Column name REPAIRS (RPRS) pk * code Key type Optionality Column name uk * PIN pk * code * surname * type_service * name o quantity_parts * address o price_parts * phone_mobile o time_work o phone_fix fk o code_service o email fk o code_part fk * post_no_city fk * no_order

VEHICLES (VHLS) ORDERS (ORDS) Key type Optionality Column name Key type Optionality Column name pk * code pk * number * registration * date * no_chasis * mileage * no_engine * price_hour * year_manufac * rabate_pts fk o code_fuel * rabate_src fk * code_owner fk * code_vehicle fk * code_model

fk * code_empl

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BILLS (BLS) price of working hour, the amount of rebates for Key type Optionality Column name parts and services and all calculated amounts. pk * number - The car part price is not a foreign key in the Correction table, but only takes the current value * date from the Parts table, because it is possible that the * var_rate price of the car part in the Parts table changes in * issued time. * paid - In the Corrections table, the column's optional * receive_bill service code, part code, part quantity, part price fk, uk * number_order and time of operation depend on the mandatory column type of service, which determines whether fk * code_empl the repair involves a service with the installation of a car part or a service that does not require the Scheme of the physical model contains all the sale and installation of the car part. necessary elements for creating a database in the DBMS and is understandable for database designers. Based on the example of the model of the car It contains tables of relational database. Plenty could service, an efficient information system can be be written about relational databases. We will briefly developed.. summarize one definition that is found in the literature: "Relational database is a set of data sets 4. Conclusions, discussions and suggestions that can be viewed at the logical level as normalized relation of corresponding degrees and dynamic The results of the research used by the authors of content. A set of relational schemes of relational this paper, show that the most striking problems of databases is a relational database scheme. Base the business of small and medium-sized enterprises, relations are relations that are defined independently including the car services themselves, are poor of other relations in the database, and which can not insight into the performed tasks and payment flows. be derived from other base relations. They are The reason for this is very often a loss of represented at the physical level by the appropriate documentation, since in car services, according to the data structures."[3] very nature of the work, there is a "mess" among the There are certain rules in the business of the car things and the documentation. service "Ključ" which can not be presented in the Also, the lack of time for paper scans and data ERD nor in the scheme structure of the database analysis in order to obtain information useful for table. Such rules are documented in order to be making decisions in relation to service users is one of observed during the creation of the interface of the the main problems. information system, with the help of the program In this regard, it is necessary to introduce code. The rules are as follows: information system into the car service, in order for

- The amount of rebate will be proposed by the the relationship with the users of the service to be information system based on a specific algorithm provided on accurate information about the history of defined by the service management. servicing their vehicle. This should lead to more - In the order, the amounts without rebates for parts efficient repairs, so that users and service managers and services shall be calculated on the basis of the are more satisfied with mutual "clean bills" and the values of the repairs, while amounts for the parts, introduction of benefits, which would be a the services and in total, the amount of the rebate consequence of the actual state of their business and the amounts for payment, will be calculated cooperation already achieved. The accuracy of the on the basis of the amount without rebates and the information would be achieved by the timely actual amount of the rebate. submission of the records and their prompt analysis - For each order it is necessary to display the and presentation in the form of reports transparent to amount without rebates in the interface, the the manager of the service. amount of the rebates and the amount for In the development of an information system, it is payment. necessary to do business analysis of the company. - There must be the ability to review reports on This leads to demands that the company's total turnover and debt of vehicle owners. The management places as a task for designers and report should include amounts from all orders developers, a task that can be solved with the help of opened for all vehicles owned by that customer. information technology. The first logical step to do is - The following data taken from the order should be modeling the system. In this paper we have taken an included in the account: the number of the order, example of a system of one car service. The Oracle the surname and name of the vehicle owner, the Corporation rules were used for modeling. In the

SAR Journal – Volume 2 / Number 1 / 2019. 45 SAR Journal. Volume 2, Issue 1, Pages 39-46, ISSN 2619-9955, DOI: 10.18421/SAR21-06 March 2019. modeling of information systems, it is the use of the References model of entity connections that is represented by a diagram. Such a diagram is called ERD. The basis of [1] Novalić, F., Selimović, F., & Saračević, M. (2011). ERD consists of important participants in the system The Importance of Information Systems in Small and (entities), their properties (attributes) and mutual Medium Companies. International scientific conference SMEPP 2011 (pp. 543-550). Novi Pazar: relationships (relations). Oracle has set convention University of Novi Pazar. on the presentation of the elements of the ERD. This [2] Oracle. (2013). eStudy 2013-2015 Database Design . allows for a proper interpretation of the conceptual Retrived from: http://ilearning.oracle.com/ model of the system by the database designer. [accessed: 04. November 2018]. Database designers, on the basis of the conceptual [3] Pavlović Lažetić, G. (1999). Introduction to model of the system, create a database that represents relational databases. : Faculty of the physical model of the system. Oracle Corporation Mathematics, . calls this process the translation of the ERD. There is [4] Speelpenning, J., Daux, P., & Gallus, J. (2001). Data also a change in terminology, which is called Modeling and Relational Database Design. Redwood mapping of terms. It is not necessary for a database City: Oracle Corporation. [5] Veinović, M., Šimić, G., Jevremović, A., & Tair, M. to be created in a Database Management System (2018). Database. Belgrade: Singidunum University. (DBMS), but it can be presented graphically. Such a [6] Veljović, A., & Njeguš, A. (2004). Basics of graphical representation contains all the necessary relational and analytical databases. Belgrade: elements for creating a database in the DBMS. of Applied Sciences. This paper provides an example of the conceptual and the physical model of the car service system, with documented business rules that can not be presented in the diagram or in the scheme of the database structure. On the basis of the presented model of the car service system, the information system was successfully developed, which achieved practical application. This proves the efficiency and justification of the use of ORACLE database design in the creation of information systems for small and medium enterprises. The authors propose that, based on the results of this paper, the development of an information system with the aim of providing better quality services will result in an increase in the volume of work, which is the ultimate goal of every entrepreneur, and that IS is realized in the form of a Web application. This would allow access to the system regardless of the location of the user. This is important primarily because a significant number of car services have multi-site operations. It would also avoid the risk of a pause in the use of the system in situations when there is a computer's fault where it is installed on, given that for the access to the Web application it is sufficient to access the Internet and any Web browser.

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