Data exchange

Data exchange is the process of taking data structured under a source schema and transforming it into a target schema, so that the target data is an accurate representation of the source data. Data exchange allows data to be shared between different computer programs.

It is similar to the related concept of data integration except that data is actually restructured (with possible loss of content) in data exchange. There may be no way to transform an instance given all of the constraints. Conversely, there may be numerous ways to transform the instance (possibly infinitely many), in which case a "best" choice of solutions has to be identified and justified.

Single-domain data exchange

In some domains, a few dozen different source and target schema (proprietary data formats) may exist. An "exchange" or "interchange format" is often developed for a single domain, and then necessary routines (mappings) are written to (indirectly) transform/translate each and every source schema to each and every target schema by using the interchange format as an intermediate step. That requires a lot less work than writing and debugging the hundreds of different routines that would be required to directly translate each and every source schema directly to each and every target schema.

Examples of these transformative interchange formats include:

• Standard Interchange Format for geospatial data;
• Data Inter chance Format for spreadsheet data;
• Open Document Format for spreadsheets, charts, presentations and word processing documents;
• GPS eXchange Format or Keyhole Markup Language for describing GPS data;
• GDSII for integrated circuit layout.

Data exchange methods

There are two types of data exchange: broadcast data exchange vs peer-to-peer (unicast) data exchange.^[1]

In a broadcast network, data is transmitted simultaneously to all participants. Just as a conference call, all participants get the exact same information from the speaker at the same time. ^[2]

In a peer-to-peer (unicast) data exchange model, data is sent only to the targeted receiver defined by a specific address. Just as a telephone call or a email, information only flows between two network participants. ^[3]

Data exchange languages

See also: Modeling language

A data interchange (or exchange) language/format is a language that is domain-independent and can be used for data from any kind of discipline.^[4] They have "evolved from being markup and display-oriented to further support the encoding of metadata that describes the structural attributes of the information."^[5]

Practice has shown that certain types of formal languages are better suited for this task than others, since their specification is driven by a formal process instead of particular software implementation needs. For example, XML is a markup language that was designed to enable the creation of dialects (the definition of domain-specific sublanguages).^[6] However, it does not contain domain-specific dictionaries or fact types. Beneficial to a reliable data exchange is the availability of standard dictionaries-taxonomies and tools libraries such as parsers, schema validators, and transformation tools.^{[citation needed]}

Popular languages used for data exchange

The following is a partial list of popular generic languages used for data exchange in multiple domains.

Name/Abbreviation	Schemas	Flexible	Semantic verification	Dictionary	Information Model	Synonyms and homonyms	Dialecting	Web standard	Transformations	Lightweight	Human readable	Compatibility
RDF	Yes[1]	Yes	Yes	Yes	Yes	Yes	Yes	Yes	Yes	Yes	Partial	Subset of Semantic web
XML	Yes[2]	Yes	No	No	No	No	Yes	Yes	Yes	No	Yes	subset of SGML, HTML
Atom	Yes	Un­known	Un­known	Un­known	No	Un­known	Yes	Yes	Yes	No	No	XML dialect
JSON	No	Un­known	Un­known	Un­known	No	Un­known	No	Yes	No	Yes	Yes	subset of YAML
YAML	No[3]	Un­known	Un­known	Un­known	No	Un­known	No	No	No[3]	Yes	Yes[4]	superset of JSON
REBOL	Yes[7]	Yes	No	Yes	No	Yes	Yes	No	Yes[7]	Yes	Yes[5]
Gellish	Yes	Yes	Yes	Yes[8]	No	Yes	Yes	ISO	No	Yes	Partial[6]	SQL, RDF/XML, OWL

Nomenclature

• Schemas – Whether the language definition is available in a computer interpretable form
• Flexible – Whether the language enables extension of the semantic expression capabilities without modifying the schema
• Semantic verification – Whether the language definition enables semantic verification of the correctness of expressions in the language
• Dictionary-Taxonomy – Whether the language includes a dictionary and a taxonomy (subtype-supertype hierarchy) of concepts with inheritance
• Synonyms and homonyms – Whether the language includes and supports the use of synonyms and homonyms in the expressions
• Dialecting – Whether the language definition is available in multiple natural languages or dialects
• Web or ISO standard – Organization that endorsed the language as a standard
• Transformations – Whether the language includes a translation to other standards
• Lightweight – Whether a lightweight version is available, in addition to a full version
• Human-readable – Whether expressions in the language are human-readable (readable by humans without training)^[7]
• Compatibility – Which other tools are possible to use or required when using the language

Notes:

1. ^ RDF is a schema-flexible language.
2. ^ The schema of XML contains a very limited grammar and vocabulary.
3. ^ Available as an extension.
4. ^ In the default format, not the compact syntax.
5. ^ The syntax is fairly simple (the language was designed to be human-readable); the dialects may require domain knowledge.
6. ^ The standardized fact types are denoted by standardized English phrases, which interpretation and use needs some training.
7. ^ The Parse dialect is used to specify, validate, and transform dialects.
8. ^ The English version includes a Gellish English Dictionary-Taxonomy that also includes standardized fact types (= kinds of relations).

XML for data exchange

The popularity of XML for data exchange on the World Wide Web has several reasons. First of all, it is closely related to the preexisting standards Standard Generalized Markup Language (SGML) and Hypertext Markup Language (HTML), and as such a parser written to support these two languages can be easily extended to support XML as well. For example, XHTML has been defined as a format that is formal XML, but understood correctly by most (if not all) HTML parsers.^[6]

YAML for data exchange

YAML is a language that was designed to be human-readable (and as such to be easy to edit with any standard text editor). Its notion often is similar to reStructuredText or a Wiki syntax, who also try to be readable both by humans and computers. YAML 1.2 also includes a shorthand notion that is compatible with JSON, and as such any JSON document is also valid YAML; this however does not hold the other way.^[8]

REBOL for data exchange

REBOL is a language that was designed to be human-readable and easy to edit using any standard text editor. To achieve that it uses a simple free-form syntax with minimal punctuation and a rich set of datatypes. REBOL datatypes like URLs, emails, date and time values, tuples, strings, tags, etc. respect the common standards. REBOL is designed to not need any additional meta-language, being designed in a metacircular fashion. The metacircularity of the language is the reason why, e.g., the Parse dialect used (not exclusively) for definitions and transformations of REBOL dialects is also itself a dialect of REBOL.^[9] REBOL was used as a source of inspiration for JSON.^[10]

Gellish for data exchange

Gellish English is a formalized subset of natural English, which includes a simple grammar and a large extensible English Dictionary-Taxonomy that defines the general and domain specific terminology (terms for concepts), whereas the concepts are arranged in a subtype-supertype hierarchy (a taxonomy), which supports inheritance of knowledge and requirements. The Dictionary-Taxonomy also includes standardized fact types (also called relation types). The terms and relation types together can be used to create and interpret expressions of facts, knowledge, requirements and other information. Gellish can be used in combination with SQL, RDF/XML, OWL and various other meta-languages. The Gellish standard is a combination of ISO 10303-221 (AP221) and ISO 15926.^[11]

See also

• Atom (file format)
• Data transfer
• Lightweight markup language
• RSS
• Comma-separated values (CSV)

References

1. Heidarzadeh, A.; Sprintson, A. (2017-03-30). "Optimal exchange of data over broadcast networks with adversaries". 2016 Information Theory and Applications Workshop (ITA). ISBN 978-1-5090-2529-9 – via IEEE.
2. "What is a Broadcast?". IONOS Digital Guide. 2023-03-20. Retrieved 2024-04-03.
3. "Unicast". IONOS Digital Guide. 2023-03-23. Retrieved 2024-04-03.
4. Billingsley, F.C. (1988). "General Data Interchange Language". ISPRS Archives. 27 (B3): 80–91. Retrieved 25 May 2018. The transformation routines will constitute a language and syntax which must be discipline and machine independent.
5. Nurseitov, N.; Paulson, M.; Reynolds, R.; Izurieta, C. (2009). "Comparison of JSON and XML Data Interchange Formats: A Case Study". Scenario: 157–162.
6. Lewis, J.; Moscovitz, M. (2009). AdvancED CSS. APress. pp. 5–6. ISBN 9781430219323. Retrieved 25 May 2018.
7. "human-readable". Oxford Dictionaries. Oxford University Press. Archived from the original on May 30, 2018. Retrieved 29 May 2018.
8. Bendersky, E. (22 November 2008). "JSON is YAML, but YAML is not JSON". Eli Bendersky's website. Retrieved 29 May 2018.
9. Sassenrath, C. (2000). "The REBOL Scripting Language". Dr. Dobb's Journal. 25 (314): 64–8. Retrieved 29 May 2018.
10. Sassenrath, C. (13 December 2012). "On JSON and REBOL". REBOL.com. Retrieved 29 May 2018.
11. van Renssen, A.; Vermaas, P.E.; Zwart, S.D. (2007). "A Taxonomy of Functions in Gellish English". Proceedings from the International Conference on Engineering Design 2007: DS42_P_230. Retrieved 29 May 2018.