Search results for "Database schema"

A summary of genomic databases: overview and discussion

2009

In the last few years both the amount of electronically stored biological data and the number of biological data repositories grew up significantly (today, more than eight hundred can be counted thereof). In spite of the enormous amount of available resources, a user may be disoriented when he/she searches for specific data. Thus, the accurate analysis of biological data and repositories turn out to be useful to obtain a systematic view of biological database structures, tools and contents and, eventually, to facilitate the access and recovery of such data. In this chapter, we propose an analysis of genomic databases, which are databases of fundamental importance for the research in bioinfo…

Grammars++ for modelling information in text

1999

Abstract Grammars provide a convenient means to describe the set of valid instances in a text database. Flexibility in choosing a grammar can be exploited to provide information modelling capability by designing productions in the grammar to represent entities and relationships of interest to database applications. Additional constraints can be specified by attaching predicates to selected nonterminals in the grammar. When used for database definition, grammars can provide the functionality that users have come to expect of database schemas. Extended grammars can also be used to specify database manipulation, including query, update, view definition, and index specification.

Migration of Relational Database to Document-Oriented Database: Structure Denormalization and Data Transformation

2015

Relational databases remain the leading data storage technology. Nevertheless, many companies want to reduce operating expenses, to make scalable applications that use cloud computing technologies. Use of NoSQL database is one of the possible solutions, and it is forecasted that the NoSQL market will be growing at a CAGR of approximately 50 percent over the next five years. The paper offers a solution for quick data migration from a relational database into a document-oriented database. We have created semi-automatically two logical levels over physical data. Users can refine generated logical data model and configure data migration template for each needed document. Data migration features…

Schema theory: A new approach?

1987

Complex objects modeling: An entity-relationship approach

1989

Facilities for complex object modeling are nowadays needed in several areas of database applications (CAD/CAM, office automation, robotics, ...). Consequently, either new models are developed, or existing ones are extended to better respond to this requirement. Current proposals in the latter category are mainly based on the relational approach (with, as major outcome, the NF2 family of models) or on functional models like DAPLEX. This paper intends to show that the entity-relationship approach may secure an equivalent result, preserving the well known advantages inherent to this approach : increased readability and graphical display of the database schema.

Schema-Based Visual Queries over Linked Data Endpoints

2019

We present the option to use the schema-based visual query tool ViziQuer over realistic Linked Data endpoints. We describe the tool meta-schema structure and the means for the endpoint schema retrieval both from an OWL ontology and from a SPARQL endpoint. We report on a store of the endpoint-specific schemas and the options to support the schema presentation to the end-user both as a class tree within the environment and as external visual diagram.

Export of Relational Databases to RDF Databases: A Case Study

2010

The vast amount of business information nowadays is stored in relational databases. For the Semantic Web vision to become a reality, we need ways how to exploit this data in form of RDF triples. The universal and commonly accepted solution for this problem still does not exist. In most cases, mapping languages are used for specification of correspondences between OWL ontology and DB schema. At the same time, these languages generally are not well suited for specification of mappings in cases when there is a substantial difference between OWL ontology and DB schema. In this paper, we describe a new model transformation-based method for specification of correspondences between the elements of…

Publish By Example

2008

We propose an approach for producing database publishing programs by example. The main idea is to interactively build an example document, representative of the program output. The system infers from this document, without ambiguity, the publishing program. The end-user does not need to know a programming language, a query language or the database schema.

ViziQuer: A Tool to Explore and Query SPARQL Endpoints

2011

The presented tool uses a novel approach to explore and query a SPARQL endpoint. The tool is simple to use as a user needs only to enter an address of a SPARQL endpoint of one's interest. The tool will extract and visualize graphically the data schema of the endpoint. The user will be able to overview the data schema and use it to construct a SPARQL query according to the data schema. The tool can be downloaded from http://viziquer.lumii.lv. There is also additional information and help on how to use it in practice.

Export of Relational Databases to RDF Databases by Model Transformations

2011

The Semantic Web is a Web of Data. To fulfill this web with data we need methods how to transfer business data from existing relational databases. In most cases, textual mapping languages are used for the specification of correspondences between relational DB schema and OWL ontology. These languages generally are rather awkward and not well-suited for the specification of mappings in cases when there is a substantial semantic gap between the source ER schema and the target OWL ontology. At the same time specification of mappings is a classical use case for graphical model transformation languages. In our previous work [10] we have proposed a new, model transformation-based method for the sp…