Methods and transformations for transforming metadata model

• US 7,185,016 B1
• Filed: 09/01/2000
• Issued: 02/27/2007
• Est. Priority Date: 09/01/2000
• Status: Expired due to Fees

• Current Assignee: International Business Machines Corporation
• Original Assignee: Cognos Incorporated (International Business Machines Corporation)
• Inventors: Rasmussen, Glenn D.
• Primary Examiner(s): Corrielus; Jean M.
• Assistant Examiner(s): To; Baoquoc N.
• Application Number:
  US09/653,827
• Time in Patent Office: 2,370 Days
• Field of Search: 707/100, 707/102, 707/103.Y, 707/10, 707/3, 707/104, 707/103.R, 707/4, 707/103.Z
• US Class Current: 1/1
• CPC Class Codes: G06F 16/25 Integrating or interfacing systems involving database management systems
• CPC Class Codes: G06Q 10/10 Office automation; Time management
• CPC Class Codes: Y10S 707/99934 Query formulation, input preparation, or translation
• CPC Class Codes: Y10S 707/99944 Object-oriented database structure

Abstract

Transformations are provided for transforming a metadata model that contains model objects. The metadata model has a multiple layers including a lower layer containing one or more lower abstraction model objects having a lower abstraction level and a higher layer containing one or more higher abstraction model objects having a higher abstraction level. The transformations transform the model objects from the lower layer to the higher layer.

Claims

1. A computer system comprising a metadata model transformer for transforming a metadata model that represents one or more data sources having physical data, the transformer comprising:

one or more data access model transformations for refining description of the physical data in the data source expressed by data access model objects in a metadata model having a data access layer containing the data access model objects having a lower degree of abstraction, a business layer containing business model objects having a higher degree of abstraction compared to the data access model objects, and a package layer containing package model objects;

one or more data access to business model transformations for constructing business model objects in the business layer based on the data access model objects in the data access layer by adding business rules for representing business concepts;

one or more business model transformations for refining the business rules expressed by the business model objects; and

one or more business to package model transformations for constructing package model objects in the package layer based on the business model objects in the business layer, whereby the package model objects provide a representation of the business concepts

wherein the metadata model is stored in a storage device.

2. A computer system as claimed in claim 1, wherein the data access model transformations refines the description by adding new data access model objects to data access model objects which are constructed via import from the data sources or one or more metadata sources.

3. A computer system as claimed in claim 1, wherein the business model transformations refine the business rules by changing the business model objects.

4. A computer system as claimed in claim 3, wherein the business model objects include business model objects which are constructed via import from one or more metadata sources.

5. A computer system as claimed in claim 1 further comprising:

one or more package model transformations for constructing a new package model object based on the package model objects in the model.

6. A computer system as claimed in claim 5, wherein the package model objects include package model objects which are constructed via import from one or more metadata sources.

7. A computer system as claimed in claim 1 further comprising:

a name mutation transformation for changing names of objects in the model based on user defined rules.

8. A computer system as claimed in claim 1, wherein the data access model transformations include a transformation which creates a new data access model object based on the data access model objects contained in the data access layer.

9. A computer system as claimed in claim 8, wherein

the data sources contain tables having columns and indexes;

the data access model objects include data access tables, data access columns and data access indexes which respectively describe information about the tables, columns and indexes in the data sources; and

the data access model transformations include a data access join constructing transformation for constructing a data access join between data access tables based on the data access indexes.

10. A computer system as claimed in claim 8, wherein

the data sources contain tables having columns and indexes;

the data access model objects include data access tables, data access columns and data-access indexes which respectively describe information about the tables, columns and indexes in the data sources; and

the data access model transformations include a data access key constructing transformation for creating a data access key for a data access table based on the data access indexes.

11. A computer system as claimed in claim 8, wherein

the data sources contain at least one of tables having columns and indexes, views having columns or files having columns or fields;

the data access model objects include at least one of data access tables, data access views, data access files, data access columns and data access indexes which respectively describe information about the tables, columns of the tables, indexes of the tables, the views, the columns of the views, the files, and the columns or fields of the files in the data sources; and

the data access model transformations include a table extract constructing transformation for constructing a table extract based on the data access tables, the data access views and the data access files.

12. A computer system as claimed in claim 8, wherein

the data access model objects include one or more logical cube, each of which defines a multidimensional space represented in a number of physical storage formats;

and

the data access model transformations include a data access cube constructing transformation for constructing data access cubes to instantiate the multidimensional space defined by each logical cube.

13. A computer system as claimed in claim 1, wherein the data access to business model transformations include a basic business model constructing transformation which obtains information about a data access model object in the data access layer, and create a business model object corresponding to the data access model object.

14. A computer system as claimed in claim 13, wherein

the business model objects include entities that exist as an implementation artifact of a many to many relationship, and business joins associated with the entities;

and

the business model transformations include a many to many join relationship fixing transformation for locating the entities, and replacing the associated business joins with a single business join.

15. A computer system as claimed in claim 13, wherein

the business model objects include entities that are related via a 1:

1 join relationship; and

the business model transformations include an entity coalescing transformation for locating the entities that are related via a 1;

1 join relationship, and coalescing the located entities into a single entity.

16. A computer system as claimed in claim 13,

the business model objects include one or more redundant joins that express the transitivity of two or more other join relationships in the business layer;

and

the business model transformations include a redundant join relationship eliminating transformation for locating the redundant joins, and eliminating the redundant joins from the business layer.

17. A computer system as claimed in claim 13, wherein

the business model transformations include a subclass relationship introducing transformation for introducing a new entity with a subclass relationship into the business layer.

18. A computer system as claimed in claim 13, wherein

the business model objects include an entity acting as a lookup table with respect to the other entity, and a business join between the entities, the business join is an associate type;

and

the business model transformations include an entity referencing transformation for locating the entity acting as a lookup table, and changing the business join which is an association type to a business join which is a reference type.

19. A computer system as claimed in claim 13, wherein

the business model transformations include an attribute usage determining transformation for determines the usage of an attribute based on how it is used by other business model objects.

20. A computer system as claimed in claim 13, wherein

the business model transformations include a date usage identifying transformation for examining attributes to determine where dates are used in the attributes.

21. A computer system as claimed in claim 1, wherein the business to package model transformations include a basic package model constructing transformation for constructing a package layer by forming a package with package model objects which corresponds to a subset of the business model objects.

22. A computer system as claimed in claim 5, wherein the package model transformations include a special package construction transformation for constructing a specific package which is usable by a specific client application from a generic package.

23. A computer system as claimed in claim 1 further comprising one or more multidimensional model transformations for a multidimensional model.

24. A computer system as claimed in claim 23, wherein the multidimensional model transformations include a measure identifying and measure dimension constructing transformation for analyzing the structure of each data source to identify entities that contain measure candidates and identifying a reasonable set of measures.

25. A computer system as claimed in claim 23, wherein the multidimensional model transformations include a category dimension and level constructing transformation for analyzing each data source, and constructing dimensions and levels for the source model.

26. A computer system as claimed in claim 24, wherein the multidimensional model transformations include a logical cube constructing transformation for constructing a set of logical cubes based on the dimensions in a corresponding data source.

27. A method for transforming in a computer system a metadata model that represent represents one or more data sources having physical data, the method comprising steps of:

refining description of physical data in the data sources expressed by data access objects in a metadata model having a data access layer containing the data access model objects having a lower degree of abstraction, a business layer containing business model objects having a higher degree of abstraction compared to the data access model objects, and a package layer containing package model objects;

constructing business model objects in the business layer based on the data access objects in the data access layer by adding business rules for representing business concepts;

refining the business rules expressed by the business model objects;

constructing package model objects in the package layer based on the business model objects in the business layer, whereby the package model objects provide a representation of the business concepts; and

storing the metadata model having the data access layer, the business layer and a package layer in a storage device.

28. A method as claimed in claim 27, wherein the step of refining the description comprises a step of adding new data access model objects to data access model objects which are constructed via import from the data sources or one or more metadata sources.

29. A method as claimed in claim 27, wherein the step of refining the business rules comprises a step of changing the business model objects.

30. A method as claimed in claim 27, wherein the step of refining the business rules uses the business model objects that include business model objects which are constructed via import from one or more metadata sources.

31. A method as claimed in claim 27, further comprising a step of constructing a new package layer based on the business model objects in the model.

32. A method as claimed in claim 31, wherein the step of constructing a new package layer uses the business model objects that include business model objects which are constructed via import from one or more metadata sources.

33. A method as claimed in claim 27 further comprising a step of changing names of objects in the model based on user defined rules.