Method for searching a database and database

Database with a plurality of elements comprising:

• a. a plurality of hierarchically structured nodes describing attributes of the elements of the database;
• b. a plurality of unique identifiers (EID) assigned to selected nodes;
• c. a reference index, that allows to derive for each unique identifier (EID) of a selected node the corresponding element of the database;
• d. one or more search indexes, which correlate unique identifiers (EID) for ancestor nodes with nodes, which can be the subject of the one or more search conditions (c0,ci, . . . ).

Method for searching within elements on the same level of a hierarchically structured database, the method comprising

• a. storing the database in a memory, wherein each of the elements has one or more hierarchically structured nodes for defining attributes of said element, and wherein one or more nodes of the searched element must fulfill one or more search conditions;
• b. selecting a plurality of nodes and assigning a unique identifier to each of the selected nodes.
• c. creating a reference index, that allows to derive for each unique identifier of a selected node the corresponding element of the database;
• d. for each of the one or more search conditions:
• retrieving a set of unique identifiers of ancestor nodes for nodes, which fulfill the respective search condition;
• e. intersecting the sets to obtain a final set of unique identifiers;
• and
• f. retrieving the searched elements based on the final set of unique identifiers and the reference index.

A memory medium comprising program instructions for searching within elements on the same level of a hierarchically structured database, wherein each of the elements has one or more hierarchically structured nodes for defining attributes of said element, and wherein one or more nodes of the searched element must fulfill one or more search conditions (c0,ci, . . . ), wherein the program instructions are executable by a processor to implement:

• a. selecting a plurality of nodes and assigning a unique identifier (EID) to each of the selected nodes;
• b. creating a reference index, that allows to derive for each unique identifier (EID) of a selected node the corresponding element of the database;
• c. for each of the one or more search conditions (c0,ci, . . . ):
• retrieving a set (L, Ei) of unique identifiers (EID) of ancestor nodes for nodes, which fulfill the respective search condition;
• d. intersecting the sets (L, Ei) to obtain a final set (L) of unique identifiers (EID);
• and
• e. retrieving the searched elements based on the final set (L) of unique identifiers (EID) and the reference index.