Making and using abstract XML representations of data dictionary metadata

• US 20070011192A1
• Filed: 07/05/2005
• Published: 01/11/2007
• Est. Priority Date: 07/05/2005
• Status: Active Grant

• Current Assignee: Oracle International Corporation (Oracle Corporation)
• Original Assignee: Oracle International Corporation (Oracle Corporation)
• Inventors: Barton, Lee
• Granted Patent: US 8,275,810 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G06F 16/288 Entity relationship models
• CPC Class Codes: G06F 16/83 Querying

Abstract

An XML representation of the metadata for objects in a database system. The XML representation is called SXML. The SXML representations of two objects that belong to the same class of objects may be compared to produce a difference representation that shows the differences between the objects. Database commands that will create or alter objects may be produced from the difference representation, as well as an XML representation of the database commands. In addition to being comparable, SXML representations have the characteristics that a given property of the metadata is expressed in only one way in the representation, that SXML does not describe properties that belong only to particular instances of the object described by the metadata, that SXML describes only properties that the user can specify when creating an object, and that SXML is easy for humans to read, understand, and write.

Claims

1. Representations of the metadata of objects in a database system, the objects belonging to classes thereof, the representations being automatically produced by the database system from the metadata, and

the representations being characterized in that:

representations of the metadata for objects belonging to the same class are automatically comparable by the database system to determine differences between the metadata for the objects.

2. The representations set forth in claim 1 further characterized in that:

a given property specified by the metadata for an object belonging to the class is expressed in only one way in the representations.

3. The representations set forth in claim 1 further characterized in that:

the representations do not include properties specified by the metadata for an object belonging to a class that belong only to a particular instance of the object.

4. The representations set forth in claim 1 further characterized in that:

the representations include only those properties specified by the metadata for an object which a user may specify when creating the object.

5. The representations set forth in claim 1 wherein the database system is a relational database system that responds to SQL and

the representations are further characterized in that:

the representations employ constructs from the BNF syntax for SQL and SQL names for objects in the metadata,

whereby the representations are easily read by human beings.

6. The representations set forth in claim 1 wherein:

the database system automatically reads the representations to produce metadata for other objects that are like the objects.

7. The representations set forth in claim 6 wherein:

the database system is a relational database system that responds to SQL and

the database system automatically produces creation DDL f from the representations of the metadata.

8. The representations set forth in claim 6 wherein:

the database system is a relational database system that responds to SQL and

the database system automatically compares representations for first ones of the objects with representations for second ones of the objects and produces ALTER DDL which, when applied to the second objects by the database system, makes the second objects like the first objects.

9. The representations set forth in claim 1 wherein:

the database system automatically reads a first representation and a second representation of the metadata for objects belonging to the same class to produce a third representation that shows the differences between the metadata of the objects represented by the first representation and the second representation.

10. The representations set forth in claim 9 wherein:

the representations are made according to the XML standard.

11. The representations set forth in claim 1 wherein:

the representations are made according to the XML standard.

12. A data storage device characterized in that:

the data storage device contains the representations set forth in claim 1.

13. Apparatus employed in a database system for comparing metadata for a set of at least two objects belonging to the same class of object,

the apparatus comprising:

a representation of the metadata for one of the set of objects;

a representation of the metadata for another of the set of objects,

the representations being such that a given property specified by the metadata for an object belonging to the class is expressed in only one way in the representations; and

a metadata comparer which compares the representation of the metadata for one of the set of objects with the representation of the metadata for another of the set of objects and produces a difference representation which represents differences between the metadata for the one object and the metadata for the other object.

14. The apparatus set forth in claim 13 wherein:

the representations do not include properties specified by the metadata for an object belonging to a class that belong only to a particular instance of the object.

15. The apparatus set forth in claim 13 wherein:

the representations include only those properties specified by the metadata for an object which a user may specify when creating the object.

16. The apparatus set forth in claim 13 further comprising:

a generator which receives the difference representation and produces a description therefrom of how the one object is to be modified to become similar to the other object.

17. The apparatus set forth in claim 16 wherein:

the database system is a relational database system and

the description is one or more ALTER DDL statements for altering the one object so that the one object is similar to the other object.

18. The apparatus set forth in claim 16 wherein:

the database system is a relational database system and

the description is an XML representation of one or more ALTER DDL statements for altering the one object so that the one object is similar to the other object.

19. The apparatus set forth in claim 16 wherein:

the representations and the difference representation are made according to the XML standard.

20. The apparatus set forth in claim 13 wherein:

the representations and the difference representation are made according to the XML standard.

21. A data storage device characterized in that:

the data storage device includes code which, when executed in the database system, implements the metadata comparer set forth in claim 13.

22. A method employed in a database system for comparing metadata for a set of at least two objects belonging to the same class of object,

the method comprising the steps of:

accessing a representation of the metadata for one of the set of objects and a representation of the metadata for another of the set of objects, the representations being such that a given property specified by the metadata for an object belonging to the class is expressed in only one way in the representations; and

comparing the representation of the metadata for one of the set of objects with the representation of the metadata for another of the set of objects; and

producing a difference representation which represents differences between the metadata for the one object and the metadata for the other object.

23. The method set forth in claim 22 wherein:

the representations do not include properties specified by the metadata for an object belonging to a class that belong only to a particular instance of the object.

24. The method set forth in claim 22 wherein:

the representations include only those properties specified by the metadata for an object which a user may specify when creating the object.

25. The method set forth in claim 22 further comprising the steps of:

accessing the difference representation; and

producing a description from the difference representation of how the one object is to be modified to become similar to the other object.

26. The method set forth in claim 25 wherein:

the database system is a relational database system; and

in the step of producing the description, the description is one or more ALTER DDL statements for altering the one object so that the one object is similar to the other object.

27. The method set forth in claim 25 wherein:

the database system is a relational database system and

in the step of producing the description, the description is an XML representation of one or more ALTER DDL statements for altering the one object so that the one object is similar to the other object

28. The method set forth in claim 25 wherein:

the representations and the difference representation are made according to the XML standard.

29. The method set forth in claim 22 wherein:

the representations and the difference representation are made according to the XML standard.

30. A data storage device characterized in that:

the device contains code which, when executed in a database system, implements the method of claim 22.