A heterogeneous database system is an automated (or semi-automated) system for the
integration
Integration may refer to:
Biology
* Multisensory integration
* Path integration
* Pre-integration complex, viral genetic material used to insert a viral genome into a host genome
*DNA integration, by means of site-specific recombinase technolo ...
of heterogeneous, disparate
database management system
In computing, a database is an organized collection of data stored and accessed electronically. Small databases can be stored on a file system, while large databases are hosted on computer clusters or cloud storage. The design of databases span ...
s to present a user with a single, unified query interface.
Heterogeneous database systems (HDBs) are computational models and software implementations that provide heterogeneous database integration.
Problems of heterogeneous database integration
This article does not contain details of
distributed database management systems (sometimes known as
federated database system A federated database system (FDBS) is a type of meta- database management system (DBMS), which transparently maps multiple autonomous database systems into a single federated database. The constituent databases are interconnected via a computer ne ...
s).
Technical heterogeneity
Different
file format
A file format is a Computer standard, standard way that information is encoded for storage in a computer file. It specifies how bits are used to encode information in a digital storage medium. File formats may be either proprietary format, pr ...
s, access
protocols, query languages etc. Often called syntactic heterogeneity from the point of view of data.
Data model heterogeneity
Different ways of representing and storing the same data. Table decompositions may vary, column names (data labels) may be different (but have the same semantics), data
encoding
In communications and information processing, code is a system of rules to convert information—such as a letter (alphabet), letter, word, sound, image, or gesture—into another form, sometimes data compression, shortened or secrecy, secret ...
schemes may vary (i.e., should a measurement scale be explicitly included in a field or should it be implied elsewhere). Also referred as schematic heterogeneity.
Semantic heterogeneity
Data across constituent databases may be related but different. Perhaps a database system must be able to integrate genomic and proteomic data. They are related—a gene may have several protein products—but the data are different (
nucleotide
Nucleotides are organic molecules consisting of a nucleoside and a phosphate. They serve as monomeric units of the nucleic acid polymers – deoxyribonucleic acid (DNA) and ribonucleic acid (RNA), both of which are essential biomolecul ...
sequences and
amino acid
Amino acids are organic compounds that contain both amino and carboxylic acid functional groups. Although hundreds of amino acids exist in nature, by far the most important are the alpha-amino acids, which comprise proteins. Only 22 alpha ...
sequences, or hydrophilic or -phobic amino acid sequence and positively or negatively charged amino acids). There may be many ways of looking at semantically similar, but distinct, datasets.
The system may also be required to present "new" knowledge to the user. Relationships may be inferred between data according to rules specified in domain
ontologies.
See also
*
Big data
*
Expert system
In artificial intelligence, an expert system is a computer system emulating the decision-making ability of a human expert.
Expert systems are designed to solve complex problems by reasoning through bodies of knowledge, represented mainly as if� ...
*
Knowledge base
A knowledge base (KB) is a technology used to store complex structured and unstructured information used by a computer system. The initial use of the term was in connection with expert systems, which were the first knowledge-based systems. ...
*
Ontology
In metaphysics, ontology is the philosophical study of being, as well as related concepts such as existence, becoming, and reality.
Ontology addresses questions like how entities are grouped into categories and which of these entities ...
References
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Database management systems