Differences
This shows you the differences between two versions of the page.
Both sides previous revision Previous revision Next revision | Previous revision | ||
tutorial:poly_db_querying [2017/07/26 14:47] – paffenholz | tutorial:poly_db_querying [2018/02/10 11:38] (current) – deleted after merging into doku.php/tutorial/poly_db_tutorial oroehrig | ||
---|---|---|---|
Line 1: | Line 1: | ||
- | ==== Querying the Database ==== | ||
- | |||
- | There are three commands that can be used to query the database: | ||
- | * '' | ||
- | * '' | ||
- | * '' | ||
- | |||
- | == Queries == | ||
- | |||
- | Queries are given as perl hashes. In its most basic form a query has the form | ||
- | { " | ||
- | for example | ||
- | { " | ||
- | Note that the database is pretty strict with types, so strings always need to be quoted, while integers should not be. The following would fail: | ||
- | { " | ||
- | You can query elements in an array with their index, e.g. | ||
- | { " | ||
- | gives polytopes with 12 edges (the entry at position one of the f-vector). | ||
- | |||
- | You can query ranges with '' | ||
- | { DIM => { ' | ||
- | to obtain polytopes of dimension less than 4. Observe the single quotation marks around '' | ||
- | { DIM => { ' | ||
- | to obtain those polytopes with dimensions between 4 and 10. | ||
- | |||
- | == Obtain Objects that Satisfy a Query == | ||
- | |||
- | |||
- | |||
- | == Count Objects that Satisfy a Query == | ||
- | |||
- | == Obtain Object '' | ||
- | |||
- | |||
- | |||