Search
Search capacities of crystallographic databases differ widely. Basic functionality comprises search by keywords, physical properties, and chemical elements. Of particular importance is search by compound name and lattice parameters. Very useful are search options that allow the use of wildcard characters and logical connectives in search strings. If supported, the scope of the search can be constrained by the exclusion of certain chemical elements.
More sophisticated algorithms depend on the material type covered. Organic compounds might be searched for on the basis of certain molecular fragments. Inorganic compounds, on the other hand, might be of interest with regard to a certain type of coordination geometry. More advanced algorithms deal with conformation analysis (organics), supramolecular chemistry (organics), interpolyhedral connectivity (‘non-organics’) and higher-order molecular structures (biological macromolecules). Search algorithms used for a more complex analysis of physical properties, e.g. phase transitions or structure-property relationships, might apply group-theoretical concepts.
Modern versions of crystallographic databases are based on the relational database model. Communication with the database usually happens via a dialect of the Structured Query Language (SQL). Web-based databases typically process the search algorithm on the server interpreting supported scripting elements, while desktop-based databases run locally installed and usually precompiled search engines.
Read more about this topic: Crystallographic Database
Famous quotes containing the word search:
“On short, still days
At the shut of the year
We search the pathways
Where the coverts were.”
—Philip Larkin (1922–1986)
“When a person doesn’t understand something, he feels internal discord: however he doesn’t search for that discord in himself, as he should, but searches outside of himself. Thence a war develops with that which he doesn’t understand.”
—Anton Pavlovich Chekhov (1860–1904)
“The search for happiness is one of the chief sources of unhappiness.”
—Eric Hoffer (1902–1983)