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Data transformation can be simple or complex based on the required changes to the data between the source (initial) data and the target (final) data. Data transformation is typically performed via a mixture of manual and automated steps.<ref name="livinglab.mit.edu">DataXFormer. Morcos, Abedjan, Ilyas, Ouzzani, Papotti, Stonebraker. An interactive data transformation tool. Retrieved from: http://livinglab.mit.edu/wp-content/uploads/2015/12/DataXFormer-An-Interactive-Data-Transformation-Tool.pdf {{Webarchive|url=https://web.archive.org/web/20190805211122/http://livinglab.mit.edu/wp-content/uploads/2015/12/DataXFormer-An-Interactive-Data-Transformation-Tool.pdf |date=2019-08-05 }}</ref> Tools and technologies used for data transformation can vary widely based on the format, structure, complexity, and volume of the data being transformed.
A [[master data]] recast is another form of data transformation where the entire database of data values is transformed or recast without extracting the data from the database. All data in a well
When the data mapping is indirect via a mediating [[data model]], the process is also called '''data mediation'''.
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'''Data mapping''' is the process of defining how individual fields are mapped, modified, joined, filtered, aggregated etc. to produce the final desired output. Developers or technical data analysts traditionally perform data mapping since they work in the specific technologies to define the transformation rules (e.g. visual [[Extract, transform, load|ETL]] tools,<ref>DWBIMASTER. Top 10 ETL Tools. Retrieved from: http://dwbimaster.com/top-10-etl-tools/ {{Webarchive|url=https://web.archive.org/web/20170829035105/http://dwbimaster.com/top-10-etl-tools/ |date=2017-08-29 }}</ref> transformation languages).
'''Code generation''' is the process of generating executable code (e.g. SQL, Python, R, or other executable instructions) that will transform the data based on the desired and defined data mapping rules.<ref>Petr Aubrecht, Zdenek Kouba. Metadata
'''Code execution''' is the step whereby the generated code is executed against the data to create the desired output. The executed code may be tightly integrated into the transformation tool, or it may require separate steps by the developer to manually execute the generated code.
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Batch data transformation is the cornerstone of virtually all data integration technologies such as data warehousing, data migration and application integration.<ref name="cio.com"/>
When data must be transformed and delivered with low latency, the term "microbatch" is often used.<ref name="tdwi.org"/> This refers to small batches of data (e.g. a small number of rows or a small set of data objects) that can be processed very quickly and delivered to the target system when needed.
===Benefits of batch data transformation===
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Once they've finished transforming the data, the system can generate executable code/logic, which can be executed or applied to subsequent similar data sets.
By removing the developer from the process, interactive data transformation systems shorten the time needed to prepare and transform the data, eliminate costly errors in the interpretation of user requirements and empower business users and analysts to control their data and interact with it as needed.<ref name="ReferenceA"/>
==Transformational languages==
There are numerous languages available for performing data transformation. Many [[transformation language]]s require a [[grammar]] to be provided. In many cases, the grammar is structured using something closely resembling [[Backus–Naur form]] (BNF). There are numerous languages available for such purposes varying in their accessibility (cost) and general usefulness.<ref>DMOZ. Extraction and Transformation. Retrieved from: https://dmoztools.net/Computers/Software/Databases/Data_Warehousing/Extraction_and_Transformation/ {{Webarchive|url=https://web.archive.org/web/20170829041136/https://dmoztools.net/Computers/Software/Databases/Data_Warehousing/Extraction_and_Transformation/ |date=2017-08-29 }}</ref> Examples of such languages include:
* [[AWK]] - one of the oldest and most popular textual data transformation
* [[Perl]] - a high-level language with both procedural and object-oriented syntax capable of powerful operations on binary or text data.
* [[Web template|Template languages]] - specialized to transform data into documents (see also [[template processor]]);
* [[TXL (programming language)|TXL]] - prototyping language-based descriptions, used for source code or data transformation.
* [[XSLT]] - the standard XML data transformation language (suitable by [[XQuery]] in many applications);
Additionally, companies such as Trifacta and Paxata have developed ___domain-specific transformational languages (DSL) for servicing and transforming datasets. The development of ___domain-specific languages has been linked to increased productivity and accessibility for non-technical users.<ref>{{Cite web|url=https://docs.trifacta.com/display/PE/Wrangle+Language|title=Wrangle Language - Trifacta Wrangler - Trifacta Documentation|website=docs.trifacta.com|access-date=2017-09-20|archive-date=2017-09-21|archive-url=https://web.archive.org/web/20170921045735/https://docs.trifacta.com/display/PE/Wrangle+Language|url-status=live}}</ref> Trifacta's “Wrangle” is an example of such a ___domain
Another advantage of the recent ___domain-specific transformational languages trend is that a ___domain-specific transformational language can abstract the underlying execution of the logic defined in the ___domain-specific transformational language. They can also utilize that same logic in various processing engines, such as [[SPARK (programming language)|Spark]], [[MapReduce]], and [[Microsoft Dataflow|Dataflow]]. In other words, with a ___domain-specific transformational language, the transformation language is not tied to the underlying engine.<ref name=":0" />
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In other words, all instances of a function invocation of foo with three arguments, followed by a function invocation with two arguments would be replaced with a single function invocation using some or all of the original set of arguments.
==See also==
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