DEVELOPMENT AND IMPLEMENTATION OF A SPECIALIZED REGULATORY REFERENCE DATABASE (DB) "SOWING EQUIPMENT FOR TILLED AND VEGETABLE CROPS”

This paper discusses the procedure for the develop-ment and operation algorithm of the specialized regulatory and reference database “Sowing equipment for tilled and vegetable crops” which contains a description and tech-nical characteristics of domestic and foreign precision seeders (their units and assemblies) for tilled and vegeta-ble crops in the system precision and zero agriculture. The main function of the program is the accumulation and sys-tematization of information on sowing equipment for tilled and vegetable crops with the possibility of interactive search, filtering and comparison of results. The structure of the database being developed has been determined; it includes 4 blocks: a graphical interface; control algorithms; data management; control components and general pur-pose components. Taking into account this structure, the stages of creating a database are determined: analysis of real world objects for the implementation of the modeling process, selection of tables and fields that are capable of identifying each object, designing relationships between tables and setting referential integrity rules. The developed software solves the following tasks: searches according to the main characteristics of sowing equipment for tilled and vegetable crops; forms an initial set of characteristics and their limit values; implements sorting and filtering of search results; provides the ability to select from the table-list a specific instance of equipment with the output of detailed information; provides the ability to select from the table-list of several copies of equipment for their detailed compari-son; provides personalized access to entering and modify-ing information in the database. The advantage of using the developed database is its regular replenishment; at the moment the information volume (content) is: for mechanical seeders -23 items; pneumatic seeders -78 items; “direct sowing” (“zero” farming) equipment -10 items.

Referential Integrity in Cloud NoSQL Databases

<p>Cloud computing delivers on-demand access to essential computing services providing benefits such as reduced maintenance, lower costs, global access, and others. One of its important and prominent services is Database as a Service (DaaS) which includes cloud Database Management Systems (DBMSs). Cloud DBMSs commonly adopt the key-value data model and are called Not only SQL (NoSQL) DBMSs. These provide cloud suitable features like scalability, flexibility and robustness, but in order to provide these, features such as referential integrity are often sacrificed. In such cases, referential integrity is left to be dealt with by the applications instead of being handled by the cloud DBMSs. Thus, applications are required to either deal with inconsistency in the data (e.g. dangling references) or to incorporate the necessary logic to ensure that referential integrity is maintained. This thesis presents an Application Programming Interface (API) that serves as a middle layer between the applications and the cloud DBMS in order to maintain referential integrity. The API provides the necessary Create, Read, Update and Delete (CRUD) operations to be performed on the DBMS while ensuring that the referential integrity constraints are satisfied. These constraints are represented as metadata and four different approaches are provided to store it. Furthermore, the performance of these approaches is measured with different referential integrity constraints and evaluated upon a set of experiments in Apache Cassandra, a prominent cloud NoSQL DBMS. The results showed significant differences between the approaches in terms of performance. However, the final word on which one is better depends on the application demands as each approach presents different trade-offs.</p>

Referential Integrity in Cloud NoSQL Databases

<p>Cloud computing delivers on-demand access to essential computing services providing benefits such as reduced maintenance, lower costs, global access, and others. One of its important and prominent services is Database as a Service (DaaS) which includes cloud Database Management Systems (DBMSs). Cloud DBMSs commonly adopt the key-value data model and are called Not only SQL (NoSQL) DBMSs. These provide cloud suitable features like scalability, flexibility and robustness, but in order to provide these, features such as referential integrity are often sacrificed. In such cases, referential integrity is left to be dealt with by the applications instead of being handled by the cloud DBMSs. Thus, applications are required to either deal with inconsistency in the data (e.g. dangling references) or to incorporate the necessary logic to ensure that referential integrity is maintained. This thesis presents an Application Programming Interface (API) that serves as a middle layer between the applications and the cloud DBMS in order to maintain referential integrity. The API provides the necessary Create, Read, Update and Delete (CRUD) operations to be performed on the DBMS while ensuring that the referential integrity constraints are satisfied. These constraints are represented as metadata and four different approaches are provided to store it. Furthermore, the performance of these approaches is measured with different referential integrity constraints and evaluated upon a set of experiments in Apache Cassandra, a prominent cloud NoSQL DBMS. The results showed significant differences between the approaches in terms of performance. However, the final word on which one is better depends on the application demands as each approach presents different trade-offs.</p>

Enhancing virtual ontology based access over tabular data with Morph-CSV

Ontology-Based Data Access (OBDA) has traditionally focused on providing a unified view of heterogeneous datasets (e.g., relational databases, CSV and JSON files), either by materializing integrated data into RDF or by performing on-the-fly querying via SPARQL query translation. In the specific case of tabular datasets represented as several CSV or Excel files, query translation approaches have been applied by considering each source as a single table that can be loaded into a relational database management system (RDBMS). Nevertheless, constraints over these tables are not represented (e.g., referential integrity among sources, datatypes, or data integrity); thus, neither consistency among attributes nor indexes over tables are enforced. As a consequence, efficiency of the SPARQL-to-SQL translation process may be affected, as well as the completeness of the answers produced during the evaluation of the generated SQL query. Our work is focused on applying implicit constraints on the OBDA query translation process over tabular data. We propose Morph-CSV, a framework for querying tabular data that exploits information from typical OBDA inputs (e.g., mappings, queries) to enforce constraints that can be used together with any SPARQL-to-SQL OBDA engine. Morph-CSV relies on both a constraint component and a set of constraint operators. For a given set of constraints, the operators are applied to each type of constraint with the aim of enhancing query completeness and performance. We evaluate Morph-CSV in several domains: e-commerce with the BSBM benchmark; transportation with the GTFS-Madrid benchmark; and biology with a use case extracted from the Bio2RDF project. We compare and report the performance of two SPARQL-to-SQL OBDA engines, without and with the incorporation of Morph-CSV. The observed results suggest that Morph-CSV is able to speed up the total query execution time by up to two orders of magnitude, while it is able to produce all the query answers.

Beyond validation: Using programmed diagnostics to learn about, monitor, and successfully complete your DH project

Digital humanities projects have long relied on various schema languages—chiefly, RELAX NG and Schematron—for validating the XML documents in their data collections; however, these languages are limited in their ability to check for consistency, coherence, and completeness across the entire project. In our work as part of “Endings”, an umbrella project that comprises four diverse digital edition projects from different fields, we have developed a methodology for checking and enforcing correctness, completeness, and coherence across the entire document set. The following article describes the various stages (what we term “levels”) of our diagnostics process, all of which are driven by XSLT (Extensible Stylesheet Language Transformations) stylesheets, and produce a human readable report. These levels include checks for referential integrity, correct entity tagging, and potential duplicates in the data set. Using examples from the Endings projects, we show how diagnostic processes not only ensure correctness in the data set, but can also aid in determining project milestones and completion dates. Diagnostics, we argue, are thus a crucial extension to schema-based validation for complex digital projects and can provide concrete ways for digital humanities projects to enforce coherence and consistency and track their progress toward completion.