Techniques for peer-to-peer replication of objects in a relational database

• US 6,889,229 B1
• Filed: 09/28/2001
• Issued: 05/03/2005
• Est. Priority Date: 09/28/2001
• Status: Active Grant

• Current Assignee: Oracle International Corporation (Oracle Corporation)
• Original Assignee: Oracle International Corporation (Oracle Corporation)
• Inventors: Wong, Lik, Muralidhar, Subramanian, Stamos, James W.
• Primary Examiner(s): AMSBURY, WAYNE P
• Application Number:
  US09/968,617
• Time in Patent Office: 1,313 Days
• Field of Search: 707/102, 707/10
• US Class Current: 707/610
• CPC Class Codes: G06F 16/275 Synchronous replication
• CPC Class Codes: Y10S 707/954 Relational
• CPC Class Codes: Y10S 707/955 Object-oriented
• CPC Class Codes: Y10S 707/99943 Generating database or data structure, e.g. via user interface

Abstract

Techniques for replicating a database object of a relational database managed by a database system from a first node on a network to a second node on the network include determining that the database object on the first node includes a user-defined object. A first routine of the database system is invoked. The first routine performs the step of copying the database object to the second node of the network. The first routine copies a name of a user-defined defined type of the user-defined object from the first node to the second node. The first routine also copies a first definition of the user-defined type from the first node to the second node. The first routine then copies a second definition of the database object from the first node to the second node. The second definition includes the name of the user-defined type. These techniques provide the benefits of peer-to-peer replication in a distributed database to users of object-relational databases that including user-defined objects.

Claims

1. A method for replicating a database object, of a relational database managed by a database system, from a first node on a network to a second node on the network, the method comprising the steps of:

determining that the database object on the first node includes a user-defined object defined by a user of the database system, and

during a replication operation that involves the first node and the second node, causing the database system to copy data that defines the database object, including data that defines the user-defined object, to the second node of the network.

2. The method of claim 1, wherein:

the user-defined object comprises a combination of elements, and

the step of causing the database system to copy the database object includes causing the database system to copy, as part of said database object, said combination of elements.

3. The method of claim 1, further comprising the step of causing the database system to copy from the first node to the second node a data structure holding a definition of the user-defined object.

4. The method of claim 1, wherein the database system performs the further steps of:

causing the database object to be instantiated on the second node; and

copying data from the database object on the first node into the database object on the second node.

5. The method of claim 1, wherein the step of causing the database system to copy the database object includes causing the database system to copy a table for logically arranging data items in rows and columns.

6. The method of claim 1, wherein the step of causing the database system to copy the database object includes causing the database system to copy a view specifying a set of rows and columns from one or more tables in the database.

7. The method of claim 1, wherein the step of causing the database system to copy the database object includes causing the database system to copy a procedure for operating on a user-defined object.

8. The method of claim 1, wherein the database object is a key column of a table of rows and columns.

9. A method for replicating a database object, of a relational database managed by a database system, from a first node on a network to a second node on the network, the method comprising the steps of:

determining that the database object on the first node includes a user-defined object defined by a user of the database system, and

causing the database system to copy the database object, including the user-defined object, to the second node of the networks wherein;

the database object is a table for logically arranging data items in rows and columns, each column having a column type, the data items in each column having a data type corresponding to the column type of the column in which the data items reside, the column types for the columns in the table stored in a data structure describing the table;

the user-defined object is a data item in a first column of a first row of the table; and

the step of causing the database system to copy the database object includes causing the database system to copy, as part of said database object, said data item from said first column of said first row of the table.

10. A method for replicating a database object, of a relational database managed by a database system, from a first node on a network to a second node on the network, the method comprising the steps of:

determining that the database object on the first node includes a user-defined object defined by a user of the database system, and

causing the database system to copy the database object, including the user-defined object, to the second node of the network, wherein the database system performs the further steps of;

copying a name of a user-defined type of the user-defined object from the first node to the second node;

copying a first definition of the user-defined type from the first node to the second node; and

after copying the first definition of the user-defined type, and after copying the name of the user-defined type, copying a second definition of the database object from the first node to the second node, the second definition including the name of the user-defined type.

11. A method for replicating a database object, of a relational database managed by a database system, from a first node on a network to a second node on the network, the method comprising the steps of:

determining that the database object on the first node includes a user-defined object defined by a user of the database system, and

causing the database system to copy the database object to the second node of the network, including performing the steps of;

copying a name of a user-defined type of the user-defined object from the first node to the second node;

copying a first definition of the user-defined type from the first node to the second node;

copying a second definition of the database object from the first node to the second node, the second definition including the name of the user-defined type;

causing the database object to be instantiated on the second node; and

copying data from the database object on the first node into the database object on the second node.

12. A method for use within a relational database system for generating on a second node a replicated database object based on a particular database object on a first node, the method comprising the steps of:

receiving, at the second node, sequence data indicating a sequence of identifiers for attributes of the particular database object;

receiving, at the second node, a series of values from the first node; and

storing the series of values at locations within the replicated database object based on the sequence data and a mapping between the attributes of the particular database object and attributes of the replicated database object.

13. The method of claim 12, wherein the sequence data also indicates a sequence of built-in types corresponding to the sequence of identifiers.

14. The method of claim 13, said step of generating the mapping further comprising the step of receiving at the second node data indicating a first identifier of the identifiers in association with a first local name of the local names.

15. The method of claim 12, further comprising the step of generating the mapping based on associating the identifiers for the attributes of the particular database object with corresponding local names for the attributes of the replicated database object.

16. The method of claim 12, wherein:

the particular database object includes a particular attribute having a user-defined type defined by a user of the relational database system based on a particular combination of leaf attributes;

each leaf attribute has a built-in type and a leaf name; and

the sequence data indicates a sequence of leaf names for the leaf attributes.

17. The method of claim 16, further comprising the step of generating the mapping at the second node based on associating the leaf names with corresponding local names for the leaf attributes of the particular attribute of the replicated database object.

18. The method of claim 17, said step of generating the mapping further comprising the steps of:

generating local names for each leaf attribute in the particular combination of leaf attributes; and

generating leaf names for each leaf attribute in the particular combination of leaf attributes.

19. The method of claim 18, further comprising the step of receiving at the second node definition data describing the user-defined type.

20. The method of claim 19, said step of generating the mapping further comprising the step of determining the particular combination of leaf attributes based on the definition data.

21. The method of claim 19, said step of generating leaf names further comprising the step of generating leaf names based at least in part on the definition data.

22. The method of claim 18, further comprising the step of receiving at the second node data that indicates a user-defined name for the particular attribute.

23. The method of claim 22, said step of generating leaf names further comprising the step of generating leaf names based at least in part on the user-defined name for the particular attribute.

24. The method of claim 16, wherein each leaf name is a fully-qualified name that includes a user-defined name for the particular attribute.

25. The method of claim 16, wherein an atomic-null attribute of the particular database object indicates whether values for the particular attribute having the user-defined type are absent in the series of values from the first node.

26. The method of claim 12, wherein a null-image attribute of the particular database object indicates whether a value for a second attribute of the particular database object is absent in the series of values from the first node.

27. The method of claim 12, wherein:

the particular database object is a database table; and

the attributes of the particular database object are columns of the database table.

28. A method for use within a relational database system for generating on a second node a replicated database object based on a particular database object on a first node, the method comprising the steps of:

determining a sequence for sending to the second node values of attributes of the particular database object;

sending to the second node sequence data indicating the sequence, the sequence data including for each attribute in the sequence a built-in type defined by the database system and a user-defined name defined by a user of the database system; and

sending to the second node a series of values from the particular database object based on the sequence.

29. A method for use within a relational database system for generating on a second node a replicated database object based on a particular database object on a first node, the method comprising the steps of:

determining a set of leaf attributes corresponding to a particular attribute of the particular database object, the particular attribute having a user-defined type defined by a user of the database system, each leaf attribute in the set having a built-in type defined by the database system and a leaf name; and

sending each value of the user-defined type that resides in the particular attribute as a set of values corresponding to the set of leaf attributes.

30. The method of claim 29, wherein:

the method further comprises the step of sending, to the second node, sequence data indicating a sequence of leaf attributes corresponding to the set of values; and

said step of sending the set of values is performed according to the sequence of leaf attributes indicated in the sequence data.

31. The method of claim 29, wherein

a first leaf attribute of the set of leaf attributes has a null-image type;

and

a value corresponding to the first leaf attribute indicates which other leaf attributes of the set of leaf attributes correspond to other values in the set of values.

32. A computer-readable medium carrying one or more sequences of instructions for replicating a database object of a relational database managed by a database system from a first node on a network to a second node on the network, 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:

determining that the database object on the first node includes a user-defined object defined by a user of the database system, and

during a replication operation that involves the first node and the second node, causing the database system to copy data that defines the database object, including data that defines the user-defined object, to the second node of the network.

33. The computer-readable medium of claim 32, wherein:

the user-defined object comprises a combination of elements; and

the step of causing the database system to copy the database object includes causing the database system to copy, as part of said database object, said combination of elements.

34. The computer-readable medium of claim 32, wherein execution of the one or more sequences of instructions by one or more processors further causes the one or more processors to perform the step of copying from the first node to the second node a data structure holding a definition of the user-defined object.

35. The computer-readable medium of claim 32, wherein execution of the one or more sequences of instructions by the one or more processors further causes the one or more processors to perform the steps of:

instantiating the database object on the second node; and

copying data from the database object on the first node into the database object on the second node.

36. The computer-readable medium of claim 32, wherein the step of causing the database system to copy the database object includes causing the database system to copy a table for logically arranging data items in rows and columns.

37. The computer-readable medium of claim 32, wherein the step of causing the database system to copy the database object includes causing the database system to copy a view specifying a set of rows and columns from one or more tables in the database.

38. The computer-readable medium of claim 32, wherein the step of causing the database system to copy the database object includes causing the database system to copy a procedure for operating on a user-defined object.

39. The computer-readable medium of claim 32, wherein the database object is a key column of a table of rows and columns.

40. A computer-readable medium carrying one or more sequences of instructions for replicating a database object of a relational database managed by a database system from a first node on a network to a second node on the network, 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:

determining that the database object on the first node includes a user-defined object defined by a user of the database system, and

causing the database system to copy the database object, including the user-defined object, to the second node of the network, wherein;

the database object is a table for logically arranging data items in rows and columns, each column having a column type, the data items in each column having a data type corresponding to the column type of the column in which the data items reside, the column types for the columns in the table stored in a data structure describing the table;

the user-defined object is a data item in a first column of a first row of the table; and

the step of causing the database system to copy the database object includes causing the database system to copy, as part of said database object, said data item from said first column of said first row of the table.

41. A computer-readable medium carrying one or more sequences of instructions for replicating a database object of a relational database managed by a database system from a first node on a network to a second node on the network, 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:

determining that the database object on the first node includes a user-defined object defined by a user of the database system;

causing the database system to copy the database object, including the user-defined object, to the second node of the network;

copying a name of a user-defined type of the user-defined object from the first node to the second node;

copying a first definition of the user-defined type from the first node to the second node; and

after copying the first definition of the user-defined type, and after copying the name of the user-defined type, copying a second definition of the database object from the first node to the second node, the second definition including the name of the user-defined type.

42. A computer-readable medium carrying one or more sequences of instructions for replicating a database object of a relational database managed by a database system from a first node on a network to a second node on the network, 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:

determining that the database object on the first node includes a user-defined object defined by a user of the database system, and

copying the database object to the second node of the network, including performing the steps of;

copying a name of a user-defined type of the user-defined object from the first node to the second node;

copying a first definition of the user-defined type from the first node to the second node;

copying a second definition of the database object from the first node to the second node, the second definition including the name of the user-defined type;

instantiating the database object on the second node; and

copying data from the database object on the first node into the database object on the second node.

43. A computer-readable medium carrying one or more sequences of instructions for use within a relational database system for generating on a second node a replicated database object based on a particular database object on a first node, wherein execution of the one or more sequences of instructions by one or more processors on the second node causes the one or more processors to perform the steps of:

receiving sequence data indicating a sequence of identifiers for attributes of the particular database object;

receiving a series of values from the first node; and

storing the series of values at locations within the replicated database object based on the sequence data and a mapping between the attributes of the particular database object and attributes of the replicated database object.

44. The computer-readable medium of claim 43, wherein the sequence data also indicates a sequence of built-in types corresponding to the sequence of identifiers.

45. The computer-readable medium of claim 44, said step of generating the mapping further comprising the step of receiving at the second node data indicating a first identifier of the identifiers in association with a first local name of the local names.

46. The computer-readable medium of claim 43, wherein the one or more sequences of instructions further cause the one or more processors to perform the step of generating the mapping based on associating the identifiers for the attributes of the particular database object with corresponding local names for the attributes of the replicated database object.

47. The computer-readable medium of claim 43, wherein:

the particular database object includes a particular attribute having a user-defined type defined by a user of the relational database system based on a particular combination of leaf attributes;

each leaf attribute has a built-in type and a leaf name; and

the sequence data indicates a sequence of leaf names for the leaf attributes.

48. The computer-readable medium of claim 47, wherein the one or more sequences of instructions further cause the one or more processors to perform the step of generating the mapping at the second node based on associating the leaf names with corresponding local names for the leaf attributes of the particular attribute of the replicated database object.

49. The computer-readable medium of claim 48, said step of generating the mapping further comprising the steps of:

generating local names for each leaf attribute in the particular combination of leaf attributes; and

generating leaf names for each leaf attribute in the particular combination of leaf attributes.

50. The computer-readable medium of claim 49, wherein the one or more sequences of instructions further cause the one or more processors to perform the step of receiving definition data describing the user-defined type.

51. The computer-readable medium of claim 50, said step of generating the mapping further comprising the step of determining the particular combination of leaf attributes based on the definition data.

52. The computer-readable medium of claim 50, said step of generating leaf names further comprising the step of generating leaf names based at least in part on the definition data.

53. The computer-readable medium of claim 49, wherein the one or more sequences of instructions further cause the one or more processors to perform the step of receiving data that indicates a user-defined name for the particular attribute.

54. The computer-readable medium of claim 53, said step of generating leaf names further comprising the step of generating leaf names based at least in part on the user-defined name for the particular attribute.

55. The computer-readable medium of claim 47, wherein each leaf name is a fully-qualified name that includes a user-defined name for the particular attribute.

56. The computer-readable medium of claim 47, wherein an atomic-null attribute of the particular database object indicates whether values for the particular attribute having the user-defined type are absent in the series of values from the first node.

57. The computer-readable medium of claim 43, wherein a null-image attribute of the particular database object indicates whether a value for a second attribute of the particular database object is absent in the series of values from the first node.

58. The computer-readable medium of claim 43, wherein:

the particular database object is a database table; and

the attributes of the particular database object are columns of the database table.

59. A computer-readable medium carrying one or more sequences of instructions for use within a relational database system for generating on a second node a replicated database object based on a particular database object on a first node, wherein execution of the one or more sequences of instructions by one or more processors on the first node causes the one or more processors to perform the steps of:

determining a sequence for sending to the second node values of attributes of the particular database object;

sending to the second node sequence data indicating the sequence, the sequence data including for each attribute in the sequence a built-in type defined by the database system and a user-defined name defined by a user of the database system; and

sending to the second node a series of values from the particular database object based on the sequence.

60. A computer-readable medium carrying one or more sequences of instructions for use within a relational database system for generating on a second node a replicated database object based on a particular database object on a first node, wherein execution of the one or more sequences of instructions by one or more processors on the second node causes the one or more processors to perform the steps of:

determining a set of leaf attributes corresponding to a particular attribute of the particular database object, the particular attribute having a user-defined type defined by a user of the database system, each leaf attribute in the set having a built-in type defined by the database system and a leaf name; and

sending each value of the user-defined type that resides in the particular attribute as a set of values corresponding to the set of leaf attributes.

61. The computer-readable medium of claim 60, wherein:

the one or more sequences of instructions further cause the one or more processors to perform the step of sending, to the second node, sequence data indicating a sequence of leaf attributes corresponding to the set of values; and

said step of sending the set of values is performed according to the sequence of leaf attributes indicated in the sequence data.

62. The computer-readable medium of claim 60, wherein

a first leaf attribute of the set of leaf attributes has a null-image type;

and

a value corresponding to the first leaf attribute indicates which other leaf attributes of the set of leaf attributes correspond to other values in the set of values.