METHOD AND SYSTEM FOR MAPPING MULTI-DIMENSIONAL MODEL TO DATA WAREHOUSE SCHEMA

• US 20080256121A1
• Filed: 04/10/2008
• Published: 10/16/2008
• Est. Priority Date: 04/13/2007
• Status: Active Grant

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Xie, Guo Tong, Liu, Sheng Ping, Yang, Yang, Qiu, Zhao Ming
• Granted Patent: US 8,099,382 B2
• Time in Patent Office: Days
• US Class Current: 707/102
• CPC Class Codes: G06F 16/283 Multi-dimensional databases or data warehouses, e.g. MOLAP or ROLAP

Abstract

A system maps a multidimensional model to data warehouse schema. The system includes a multidimensional model editor for defining a multidimensional model based on a conceptual model; a mapping reasoner for generating more simple mappings from basic mappings by reasoning on the conceptual model so as to provide mappings for concerning elements in an ontology path in the multidimensional model; a data warehouse schema analyzer for generating a data structure capable of indicating information of the data warehouse schema by making an analysis on the information of the data warehouse schema; and a mapping composition engine for generating result mappings according to mappings for the concerning elements of the ontology path in the multidimensional model and by searching in the data structure paths corresponding to the concerning elements of the ontology path in the multidimensional model. A method and computer program product are also disclosed.

Claims

1. A system for mapping multidimensional model to data warehouse schema, comprising:

a multidimensional model editor for defining a multidimensional model based on a conceptual model;

a mapping reasoner for generating more simple mappings from basic mappings by reasoning on the conceptual model so as to provide mappings for concerning elements in an ontology path in the multidimensional model;

a data warehouse schema analyzer for generating a data structure capable of indicating information of the data warehouse schema by making an analysis on the information of the data warehouse schema; and

a mapping composition engine for generating result mappings according to mappings for the concerning elements of the ontology path in the multidimensional model and by searching in the data structure paths corresponding to the concerning elements of the ontology path in the multidimensional model.

2. The system according to claim 1, comprising:

a user interface for supporting selection of the result mappings.

3. The system according to claim 1, wherein the basic mappings comprise mappings from each element in the conceptual model to the data warehouse schema, and the basic mappings are built in advance.

4. The system according to claim 1, wherein the mapping reasoner employs at least following reasoning rules:

a class inherits all the mappings of its subclasses; and

a property inherits all the mappings of its sub-properties.

5. The system according to claim 1, wherein the data warehouse schema analyzer indicates the information of the data warehouse schema in terms of a functional dependency graph.

6. The system according to claim 5, wherein the mapping composition engine is further configured for:

obtaining sets of start nodes and end nodes in the functional dependency graph corresponding to the ontology path; and

searching shortest paths in the functional dependency graph based on the sets of start ends and end nodes.

7. The system according to claim 5, wherein the functional dependency graph is a weighted and directed graph, and weights of the respective edges in the directed graph are adjustable, and wherein the mapping composition engine is further configured for ranking the result mappings according to current weights in the functional dependency graph so as to be selected by the user.

8. The system according to claim 7, wherein the mapping composition engine ranks the result mappings according to the following expression:

Rank(p)=weight(p)+α

×

(1−

|S_m∩

S_p|/|S_m|), 0<

α

<

1

wherein p is the obtained shortest path, S_m is the set of nodes in the functional dependency graph corresponding to the class and properties other than the start class (C1) and end property, and S_p is the set of the nodes which the path p covers.

9. A method for mapping a multidimensional model to data warehouse schema, comprising the steps of:

defining a multidimensional model based on a conceptual model;

generating more simple mappings from basic mappings by reasoning on the conceptual model so as to provide mappings for concerning elements in an ontology path in the multidimensional model;

generating a data structure capable of indicating information of the data warehouse schema by making an analysis on the information of the data warehouse schema; and

generating result mappings according to mappings for the concerning elements of the ontology path in the multidimensional model and by searching in the data structure paths corresponding to the concerning elements of the ontology path in the multidimensional model.

10. The method according to claim 9, comprising the step of:

selecting the result mappings.

11. The method according to claim 9, wherein the basic mappings comprise mappings from each element in the conceptual model to the data warehouse schema, and the basic mappings are built in advance.

12. The method according to claim 9, wherein reasoning rules employed in the step of generating more simple mappings from the basic mapping comprise:

a class inherits all the mappings of its subclasses; and

a property inherits all the mappings of its sub-properties.

13. The method according to claim 9, wherein the information of the data warehouse schema is indicated in terms of a functional dependency graph.

14. The method according to claim 13, further comprising the steps of:

obtaining sets of start nodes and end nodes in the functional dependency graph corresponding to the ontology path; and

searching shortest paths in the functional dependency graph based on the sets of start ends and end nodes.

15. The method according to claim 13, wherein the functional dependency graph is a weighted and directed graph, and weights of the respective edges in the directed graph are adjustable, and wherein the method further comprises the step of:

ranking the result mappings according to current weights in the functional dependency graph so as to be selected by the user.

16. The method according to claim 15, wherein the result mappings are ranked according to the following expression:

Rank(p)=weight(p)+α

×

(1−

|S_m∩

S_p|/|S_m|), 0<

α

<

1

wherein p is the obtained shortest path, S_m is the set of nodes in the functional dependency graph corresponding to the class and properties other than the start class (C1) and end property, and S_p is the set of the nodes which the path p covers.