Mechanism to efficiently index structured data that provides hierarchical access in a relational database system

• US 7,366,708 B2
• Filed: 09/27/2002
• Issued: 04/29/2008
• Est. Priority Date: 02/18/1999
• Status: Expired due to Term

• Current Assignee: Oracle International Corporation (Oracle Corporation)
• Original Assignee: Oracle Corporation
• Inventors: Jalali, Neema, Sedlar, Eric, Murthy, Ravi, Agarwal, Nipun
• Primary Examiner(s): Lee; Wilson
• Assistant Examiner(s): Nguyen; Merilyn P
• Application Number:
  US10/260,381
• Publication Number:
  US 20030033285A1
• Time in Patent Office: 2,041 Days
• Field of Search: 707 1-1041, 707/202, 726/2
• US Class Current: 707/741
• CPC Class Codes: G06F 16/284 Relational databases
• CPC Class Codes: Y10S 707/954 Relational
• CPC Class Codes: Y10S 707/99931 Database or file accessing
• CPC Class Codes: Y10S 707/99932 Access augmentation or optimizing
• CPC Class Codes: Y10S 707/99939 Privileged access

Abstract

Described is a hierarchical index that captures the hierarchical relationship of a hierarchy emulated by a relational database system. The hierarchical index is implemented, using a database table which contains rows that serve as entries of the hierarchical index. Another table has rows that are associated with nodes in the hierarchy. Each entry in the hierarchal index maps to a row that corresponds to a node in the hierarchy. A node in the hierarchy may be a parent node with one or more child nodes. In this case, the corresponding entry in the hierarchical index contains identifiers which identify other entries in the index, where the other entries correspond to rows associated with child nodes of the parent node.

Claims

1. A method used for resolving a path name that has a sequence of path elements, comprising the steps of:

traversing an index to resolve said path name;

wherein said index comprises at least a first entry that corresponds to a first path element of said sequence of path elements, wherein said first entry corresponds to a first node in an information hierarchy, wherein said first entry includes data identifying a second entry in said index that coffesponds to a second node that is a child of said first node;

wherein said second entry corresponds to a second path element from said sequence of path elements;

wherein access control data in the second entry indicates access privileges of one or more users for an item associated with the second path element;

wherein traversing said index further comprises;

accessing in said first entry said data identifying said second entry in said index;

based on the data accessed in said first entry identifying the second entry, accessing the second entry that corresponds to said second path element from said sequence of path elements; and

based on examining said access control data accessed in the second entry, determining and storing the access privileges of the item associated with the second path element.

2. The method of claim 1, wherein:

at least one path element follows said second path element in said sequence; and

the steps further include attempting to access an entry in said index that corresponds to said at least one path element only if said user may access said item according to said access privileges.

3. The method of claim 1, wherein said item is a row in a table that contains rows that correspond to nodes in a hierarchy.

4. The method of claim 1, wherein the step of determining whether a user may access the item includes determining whether the user is permitted to access an item associated with any descendant node of the second node.

5. The method of claim 1,

wherein each entry of a plurality of entries within said index is associated with an identifier that uniquely identifies said each among said plurality of entries;

and

wherein said data identifying said second entry in said index comprises the identifier that uniquely identifies said second entry.

6. The method of claim 1, wherein said access privileges further comprise any one of:

the right to read content of an item;

the right to write content of an item;

the right to define user privileges for an item;

the right to delete an item;

or

the right to traverse an item.

7. A computer-readable storage medium storing one or more sequences of instructions used for resolving a path name that has a sequence of path elements, wherein execution of the one or more sequences of instructions by one or more processors causes the one or more processors to perform the steps of:

traversing an index to resolve said path name;

wherein said index comprises at least a first entry that corresponds to a first path element of said sequence of path elements, wherein said first entry corresponds to a first node in an information hierarchy, wherein said first entry includes data identifying a second entry in said index that corresponds to a second node that is a child of said first node;

wherein said second entry corresponds to a second path element from said sequence of path elements;

wherein access control data in the second entry indicates access privileges of one or more users for an item associated with the second path element;

wherein traversing said index further comprises;

accessing in said first entry said data identifying said second entry in said index;

based on the data accessed in said first entry identifying the second entry, accessing the second entry that corresponds to said second path element from said sequence of path elements; and

based on examining said access control data accessed in the second entry, determining and storing the access privileges of the item associated with the second path element.

8. The computer-readable storage medium of claim 7, wherein:

at least one path element follows said second path element in said sequence; and

the steps further include attempting to access an entry in said index that corresponds to said at least one path element only if said user may access said item according to said access privileges.

9. The computer-readable storage medium of claim 7, wherein said item is a row in a table that contains rows that correspond to nodes in a hierarchy.

10. The computer-readable storage medium of claim 7, wherein the step of determining whether a user may access the item includes determining whether the user is permitted to access an item associated with any descendant node of the second node.