tutorial:poly_db_querying

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tutorial:poly_db_querying [2017/08/03 21:47] – paffenholztutorial:poly_db_querying [2017/08/09 09:46] – paffenholz
Line 81: Line 81:
        $p=$a->next;        $p=$a->next;
        print $p->N_LATTICE_POINTS;        print $p->N_LATTICE_POINTS;
 +       
 +=== Obtain Information about Searchable Fields in a Collection ===
 +
 +You can list all searchable entries of a collection with the command ''db_print_searchable_fields'' that takes the name of a database and a collection inside this database. 
 +<code>
 +db_print_searchable_fields(db=>"LatticePolytopes",collection=>"SmoothReflexive");
 +
 +Entries for smooth reflexive polytopes in dimensions 1 to 7
 +----------------------------
 +AFFINE_HULL  [dense, int]
 +CENTROID
 +CONE_AMBIENT_DIM  [int]
 +CONE_DIM  [int]
 +EHRHART_POLYNOMIAL_COEFF
 +FACETS  [dense, int]
 +FACET_WIDTHS  [int]
 +FULL_DIM  [int]
 +F_VECTOR  [int]
 +GORENSTEIN  [int]
 +H_STAR_VECTOR  [int]
 +[...]
 +
 +Entries for smooth reflexive polytopes in dimension 8
 +----------------------------
 +AFFINE_HULL  [dense, int]
 +[...]
 +
 +Entries for smooth reflexive polytopes in dimension 9
 +----------------------------
 +AFFINE_HULL  [dense, int]
 +[...]
 +</code>
 +
 +There may be more than one list of searchable properties, e.g. if some properties cannot be stored or computed for some objects. Observe the header line of the list of properties to see which list applies to the objects you are looking for. The above lists apply to smooth reflexive polytopes in dimensions 1 to 7, in dimension 8 and in dimension 9. If a property appears in more than one list any search for this property will be executed on all objects that belong to one of the lists. 
 +       
 +=== Type Information ===
 +
 +For most objects in the database there is a corresponding type information entry that specifies the properties present in the objects following this type information and some metadate information on the objects. Usually this is only interesting when inserting the objects into the database to ensure that all objects in a collection contain the same information (to allow comprehensive searches on the data). There can be more than one type information entry for a collection, e.g. if for some part of a collection should or cannot be computed or stored in the database (e.g. storing all lattice points for the nin-dimensional Fano polytopes is not feasible). To distinguish between these type information entries each entry in the database has a key specifying the type information used. In the objects retrieved from the database this is stored in the ''polyDB''-attachment as the property ''key''.
 +
 +You can retrieve the type information entry with ''db_get_type_information''. For example
 +   $t = db_get_type_information(db=>"LatticePolytopes", collection=>"SmoothReflexive", type_information_key=>'fano');
 +   
 +For the format of such a type information entry in the database see [[devel/polydb/format|here]].