One of the main aspects of studying databases in higher education institutions by future IT specialists is database design and software product development. This, in turn, is the most important problem of the developer's interaction with the customer. To facilitate the process of database design, ER-diagrams are used, which are based on the concepts of “Entity” and “Relationship”. An ER diagram allows you to present a database in the form of visual graphical objects that define a specific subject area. The article considers the available cloud services for the construction of ER-diagrams for learning databases of future IT specialists and their selection the method expert evaluation. For this purpose, the criteria and indicators for the selection of cloud services for the construction of ER-diagrams of databases by future information technology specialists have been determined. As a result, it was found that the cloud services Dbdesigner.net and Lucidchart are the most convenient to learn. It is determined that for a teacher of a higher education institution the use of cloud services is an opportunity to use licensed software in education without additional costs.
One of the main aspects of studying the discipline “Databases” in higher education institutions by future information technology specialists is database design and soft-ware product development, which in turn is the most important problem of interaction between the developer and the customer. While studying it, students should realize that the task of the developer is to reproduce the wishes of the customer as accurately as possible by developing a database management software product. Therefore, the main problem that future IT professionals need to learn to solve is the correct construction of a database diagram. To do this, future developers must study in detail the subject area of the database and make the requirements of the customer. The result of this work should be a database that is clear and that most accurately reflects the problem to be solved and does not contain redundant data.
To facilitate the database design process, ER charts are used, which are based on the concepts of “Entity” and “Relationship”. ER diagram allows you to present a data-base in the form of visual graphical objects that define a specific subject area. 1.1. Analysis of recent research and publications Many scientific papers are devoted to database theory (DB), database normalization processes, database design methodology, database architecture, consideration and description of modern DBMS, SQL query language, etc.
Dowming Yeh and Yuwen Li and William Chu investigated the possibilities of extracting the
diagram of the relationship of the entity from the table of an outdated database [
Paul Schmieder, Beryl Plimmer, Gillian Dobbie consider the possibilities of computer tools
for building sketches for informal sketching and automatic conversion into oficial submissions
[
Another group of authors (P. S. Dhabe, M. S. Patwardhan, Asavari A. Deshpande, M. L. Dhore, B.V. Barbadekar and H. K. Abhyankar) considered the Articulated Entity-Relationship, which was considered an extension of the Entity-Relationship diagram. The researchers considered these types of diagrams as an integral part to fully automate normalization in the case of placing information about functional dependence [3].
A group of authors (Xiong Jing, Liu Yong-ge, Gao Feng, Wang Ji-peng) analyzed the similarities between the model of entity relationships and the model RDF (model for representing named properties and property values), also, proposed ideas and processes of transformation. The researchers also implemented the Oracle Bone Inscriptions ontology using a transformation method that requires manual intervention during the transformation process [4].
Other scientists (Alexander L. Hayes, Mayukh Das, Phillip Odom and Sriraam Natarajan) have proposed a convenient automatic construction of background knowledge by constructing a mode from ER diagrams. The authors have developed a graphical user interface that allows a domain expert to interact with the system using entity relationship diagrams used to build modes for the learning system [5].
Cloud technology has been studied by many scientists [6, 7, 8, 9, 10, 11, 12]. In particular, Albert A. Azaryan, Kateryna P. Osadcha, Viacheslav V. Osadchyi, Svitlana V. Symonenko, Svitlana O. Sysoieva, investigated cloud technologies for enhancing communication of IT professionals [13]. Nataliya O. Kushnir, Viacheslav V. Osadchyi, Nataliia V. Valko considered cloud technologies for STEM education [14], Svitlana L. Proskura and Svitlana H. Lytvynova considered the approaches to Web-based education of computer science bachelors in higher education institutions [15]. Oksana M. Markova, Serhiy O. Semerikov, Andrii M. Striuk, Hanna M. Shalatska, Pavlo P. Nechypurenko and Vitaliy V. Tron investigated the implementation of cloud service models in training of future information technology specialists [9].
However, the question of appropriate selection of cloud services for the construction of ER-diagrams for training databases of future information technology professionals has not been explored, so this will be the purpose of this article.
Methods of analysis and generalization were used to determine the criteria and indicators for the selection of cloud services.
To determine the most important cloud services for the construction of ER-diagrams of
databases that can be used in the educational process of future specialists in information
technology, the method of expert evaluation was used [
Experts were involved in this method twice. The first stage of involving experts was to determine the most efective cloud services for building ER-diagrams of databases. At this stage, experts and teachers of higher education institutions were involved as experts, which in one way or another are related to the database learning of IT specialists (17 people).
For consideration by ranking experts, 12 diferent cloud services were proposed to build ER-diagrams of databases that can be used in the training of databases of future information technology professionals.
Experts were ofered a scoring system [
The main parameter for assessing significance is its total rank , which is calculated by the
formula [
= ∑︁ , ,
=1 where is the total rank of the -th indicator; = 1, 2, 3, . . . , ; is the number of indicators; – number of experts; , – the rank of the -th indicator, determined by the -th expert.
Besides, to determine the level of agreement between experts, it is necessary to calculate the
Kendell concordance coeficient [
(2) (2) = 12 · (2) 2(3 − ) = − 0.5 · ( + 1),
(2) = ∑︁ ,
2 =1
After the calculations, if the value obtained difers significantly from zero, it indicates that there is an objective agreement between the experts and therefore the total rankings are quite objective.
The second stage of involving experts was to select the most important cloud services for building ER-diagrams of databases according to certain criteria and indicators. At this stage, 15 respondents were involved to test the manifestation of each of these criteria for each of the selected cloud services to build ER-diagrams of databases.
At this stage, respondents were asked to evaluate all indicators for each criterion. Evaluation
of indicators was proposed to be carried out on a well-known scale [
The degree of manifestation of the criterion was determined by the following scale: if 76% – 100% of its indicators are positive, the criterion is characterized by the high expression, 56% – 75% – suficient manifestation, 50% – 55% – critical manifestation, if less than 50% of its indicators were positive – the criterion is considered insuficiently manifested.
To build an ER-diagram of the database at the logical and conceptual levels, we propose to use cloud services. Such tools help to design a database to better form the ideal data structure according to customer needs.
We share the opinion of Mariia P. Shishkina and Maiia V. Marienko, who note that cloud
services are used to provide the user with electronic educational resources, as well as to ensure
the processes of creation and supply of educational services [
The use of cloud services in the training of future specialists in information technology opens the way to individualization of learning, interactive interaction, and active cooperation between participants in the educational process.
Consider in detail the available cloud services for building ER-diagrams of databases. Note that we will consider completely free services or those that have a free tarif plan, but with some limitations of functionality.
Erwin Data Modeler [
Cloud service SQL DBM [
Toad Data Modeler [
Gen My Model [
Valentina [
Lucidchart [
This service is characterized by: • export the edited database schema to SQL and transfer it from Lucidchart to the database at the user’s choice, • support for the most common DBMS platforms, including MySQL, Oracle, PostgreSQL, and SQL Server, • intuitive interface, • import and export of Microsoft Visio documents, • conversion of results into PDF, JPG, PNG, • ready-made templates and forms, • quick addition or merging of objects, • adding images; • adding schemes to blog or wiki pages, • version control with preservation of previous developments, • group chat, • post-it comments; • distribution of images and samples, etc.
The free version includes the creation of 3 documents (up to 60 objects per document), access to a limited set of ready-made templates, as well as available integration with the disk, documents, spreadsheets, presentations, and e-mail from Google and Microsoft.
In the free plan of the cloud service, Creately [
The functionality includes: establishing joint work between users, creating joint projects, adding comments when working in a team, the ability to share charts with other users, monitoring of project changes.
Each change is saved, but the user can easily revert to previous versions of documents. The service has a large library of forms and templates, ofers unlimited possibilities and diferent types of charts and visual efects, export charts to PDF, JPG or PNG, image import, Drag & Drop support, ofers work with JIRA, Confluence, GoogleApps, and more.
Dbdesigner.net [
The QuickDBD [
Vertabelo [
At any time, you can see the SQL preview that will be generated for the selected item. It is also possible to share your baseline models at three diferent levels of access: Owner, Editor, and Viewer. In this service, when working together, it is possible only one user to edit the model, for others it is read-only, everyone can see the changes in the model immediately after an autosave.
If the user wants to share the model with other users, but they do not want to create Vertabelo accounts, it is possible to create a public link to the model or send it via e-mail. Thus, there is a visualization of the database data structure and joint work on it.
Vertabelo cloud service is fully accessible to students, teachers, and non-profit organizations, provided that it is used only for educational or non-profit purposes.
DModelAid [
Characteristic features of this service are: • allows you to visualize tables with keys, indexes, and links, • supports keyboard shortcuts for easy access, • automatically documents the created database project, • perform physical design using the following databases: Microsoft SQL Server, Oracle,
MySQL, SQLite, MS Access, • supports SQL queries, • allows you to export a script from a project to create physical databases, • change the database at any time, and it will be correlated with the data type and so on.
Draw.io cloud service [
At the first stage of the expert evaluation method, the experts were ofered a survey, which proposed to rank the following cloud services to build ER-diagrams of databases: 1) Creately; 2) Dbdesigner.net; 3) DModelAid; 4) Draw.io; 5) ErwinDataModeler; 6) GenMyModel; 7) Lucidchart; 8) QuickDBD; 9) SQL DBM; 10) ToadDataModeler; 11) Valentina; 12) Vertabelo.
According to the results of the survey, the relevant data on the ranking of the proposed cloud services for the construction of ER-diagrams of databases were obtained (see table 1).
According to the results of the survey, the following cloud services were selected: Dbdesigner.net, ErwinDataModeler, Lucidchart, SQL DBM.
Based on experimental data (see table 1), we calculate the Kendell concordance coeficient according to formulas (1) – (4). As a result, we have = 0.64. Since difers significantly from 0, there is an objective agreement between the experts and the total ranks are fairly objective. 6
The analysis of the available cloud services for the construction of database charts allowed to identify the following criteria and relevant indicators for the selection of cloud services for the construction of ER-charts of databases: 1) design-didactic: integration of diferent technologies for creating databases (1.1); model for a DB (1.2); setting up SQL queries (1.3); collaboration (1.4); key fields and links (1.5); the ifnal view of the database schema (1.6); 2) technological: access rights (2.1); availability of templates (2.2); communication capability (2.3); cloud data storage (2.4); free of charge (2.5); 3) functional: import of existing database diagrams (3.1); project settings (3.2); version control (3.3); export to various formats (3.4).
The design-didactic criterion characterizes the service for designing ER-diagrams of databases and its didactic component: • The indicator “integration of diferent technologies for creating databases” provides for the creation of charts for the following databases: MSSQL, MySQL, PostgreSQL, SQLite, NoSQL, etc. • The indicator “model for a DB” provides the ability to automatically create a chart based on an existing database. • The indicator “setting up SQL queries” characterizes the ability to generate an SQL script. • The indicator “collaboration” provides an opportunity to work together on the project, which is the basis of project work for future professionals in information technology. • The indicator “key fields and links” characterizes the ability to identify key fields and establish relationships between tables. • The indicator “the final view of the database schema” characterizes the appearance of the ifnal diagram of the database, its readability, and intelligibility.
The resulting data on the indicators of design-didactic criteria for each of the selected cloud services for the construction of ER-diagrams of databases contains table 2.
The technological criterion characterizes the technical capabilities of cloud services for the construction of database diagrams, and includes the following indicators: • “Access rights”, which provides access to the created database diagram at diferent levels. • “Availability of templates”, which characterizes whether this service has ready-made templates for quick creation of a database diagram. • “Communication capability” means the ability to chat with other users who have accessed this chart. • “Cloud data storage” characterizes the ability to store the created charts in the data warehouse.
• “Free of charge” means free access to the cloud service or its specific functionality.
The resulting data on the indicators of the technological criterion for each of the selected cloud services for the construction of ER-diagrams of databases are contained in table 3.
The functional criterion characterizes the available functionality of the cloud service for building ER-diagrams of databases. Consider in detail all the indicators of this criterion. • The indicator “import of existing database diagrams” provides the ability to import an existing database diagram and the ability to refine it. • The “project settings” indicator provides the ability to change project settings, such as copying or moving columns between tables, viewing only table names or only keys, and more. • The “version control” indicator provides an opportunity to compare diferent versions of the constructed diagrams to one DB. • The indicator “export to various formats” provides the ability to present the results of work in the cloud service in various formats, including pdf, jpg, png, etc.
The resulting data on the indicators of the functional criterion for each of the selected cloud services for the construction of ER-diagrams of databases are contained in table 4. The generalized results are presented in table 5.
Thus, as research shows, the most convenient and high-quality tools among cloud services for building ER-diagrams of databases on the manifestation of all criteria were Dbdesigner.net and under certain conditions Lucidchart.
These services allow you to quickly and eficiently design a database based on the built ER-diagrams, which in turn are used for research and development of software and information systems for business.
Therefore, the construction of ER-diagrams of databases by future IT professionals is convenient to do using cloud services for the purpose, which significantly speeds up the process, as it saves time (does not require installation, configuration, and upgrade), allow students to work in pairs and small groups, in free versions there is enough functionality for training.
Criteria and indicators for the selection of cloud services for building ER-diagrams of databases by future information technology specialists have been determined, according to which it has been established that the services Dbdesigner.net and Lucidchart are the most convenient to learn. For a teacher of higher education, the use of cloud services is an opportunity to use licensed software in education at no additional cost.
Thus, the importance and timeliness of the introduction of such services in the training of databases of future information technology professionals will help improve the educational process of the discipline “Databases”.
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