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Astronomical Data Query Language
Astronomical Data Query Language (ADQL) is a language for astronomical data query based on SQL 92. Overview ADQL is a specialized variant of the SQL query language adapted for accessing the astronomical datasets of the virtual observatory, via the Table access protocol (TAP). ADQL is dedigned to handle large datasets distributed over several locations, while not retrieving data that is not needed. Language ADQL is a query language Query languages, data query languages or database query languages (DQL) are computer languages used to make queries in databases and information systems. A well known example is the Structured Query Language (SQL). Types Broadly, query language ... that allows data to be retrieved via a single command, the ''select'' statement, which is designed to perform as the ''select'' statement in the SQL language. ADQL has extensions designed to improve handling of astronomical data such as spherical co-ordinates that are not handled by standard SQL. I ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Query Language
Query languages, data query languages or database query languages (DQL) are computer languages used to make queries in databases and information systems. A well known example is the Structured Query Language (SQL). Types Broadly, query languages can be classified according to whether they are database query languages or information retrieval query languages. The difference is that a database query language attempts to give factual answers to factual questions, while an information retrieval query language attempts to find documents containing information that is relevant to an area of inquiry. Other types of query languages include: * Full-text. The simplest query language is treating all terms as bag of words that are to be matched with the postings in the inverted index and where subsequently ranking models are applied to retrieve the most relevant documents. Only tokens are defined in the CFG. Web search engines often use this approach. * Boolean. A query language that also ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
TOPCAT (software)
TOPCAT is an interactive graphical viewer and editor for tabular data. Although a general purpose tool capable of handling large and sparse datasets with correlation functionality its specialist application area is astronomy and it was initially designed to support virtual observatories. It is able to handle several digital file formats including FITS which is in common use in astronomy. The Acronym ''TOPCAT'' derives from ''Tool for OPerations on Catalogues And Tables''. History The project was initially developed by Mark Taylor, an astrophysicist from the University of Bristol in 2003. Taylor acknowledges inspiration for some features from ''Mirage'' from Bell Labs and ''VOPlot'' from VO-India. Initially funded from the Starlink Project it has been funded by various other projects since. Features Written in Java, TOPCAT can be used both standalone and within a web browser. It is suitable for use as a graphical viewer and data editor of tabular data from FITS and o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |