Indexing XML documents efficiently
First Claim
1. A method for providing access to data for nodes of an information hierarchy, wherein said data for said nodes are stored in a plurality of rows of a table, the method comprising the steps of:
- generating a plurality of hash values that reflects an order of a plurality of pathnames associated with said nodes;
wherein each pathname of said plurality of pathnames corresponds to a row of said plurality of rows and identifies a location within the information hierarchy of a node whose data is stored in the row; and
storing said plurality of hash values in a data structure that associates said plurality of hash values with said plurality of rows.
1 Assignment
0 Petitions
Accused Products
Abstract
Information hierarchies are efficiently stored and accessed in a relational or object-relational database system. A path signature, similar to a pathname, is stored in a database system in association with data for the node identified by the pathname. For example, a path signature identifying an element is stored in a row that holds data for the element. To retrieve data for a hierarchical query that identifies the data requested using, for example, an XPATH string, a string pattern is generated that is matched by path signatures identified by the XPATH string. Pattern matching is then used to select rows associated with matching path signatures, and data from the selected rows is used to compute the XPATH query. Furthermore, hash values representing path signatures are generated in a way that preserves the ordering of data in an information hierarchy. The hash values can be indexed to provide quick access.
-
Citations
19 Claims
-
1. A method for providing access to data for nodes of an information hierarchy, wherein said data for said nodes are stored in a plurality of rows of a table, the method comprising the steps of:
-
generating a plurality of hash values that reflects an order of a plurality of pathnames associated with said nodes;
wherein each pathname of said plurality of pathnames corresponds to a row of said plurality of rows and identifies a location within the information hierarchy of a node whose data is stored in the row; and
storing said plurality of hash values in a data structure that associates said plurality of hash values with said plurality of rows. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16)
-
-
17. A computer-readable medium, comprising:
-
a table with a plurality of rows, each row of said plurality of rows storing data for a node of a plurality of nodes in an information hierarchy;
an index of said table having a plurality of hash values as key values within said index, wherein each hash value of said plurality of hash values corresponds to a pathname associated with a node of said plurality of nodes;
wherein the pathnames associated with the plurality of the nodes have an order; and
wherein said plurality of hash values reflects said order. - View Dependent Claims (18, 19)
-
Specification