Time-range locking for temporal database and branched-and-temporal databases

• US 20070050429A1
• Filed: 08/26/2005
• Published: 03/01/2007
• Est. Priority Date: 08/26/2005
• Status: Abandoned Application

• Current Assignee: Centric Software, Inc. (Dassault Systemes SA)
• Original Assignee: Centric Software, Inc. (Dassault Systemes SA)
• Inventors: Goldring, Robert, Gorvitovskiy, Yuriy
• Application Number:
  US11/213,258
• Publication Number:
  US 20070050429A1
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G06F 16/2315 Optimistic concurrency control
• CPC Class Codes: G06F 16/2336 Pessimistic concurrency control approaches, e.g. locking or multiple versions without time stamps
• CPC Class Codes: G06F 16/2477 Temporal data queries

Abstract

A method of accessing a version of a row in a temporal database includes checking at least a timestamp associated with the version of the row against a lock criteria for the row. Based on a result of the checking step, it is determined whether to access the version of the row. The version of the row is accessed without acquiring a lock for the row.

Claims

1. A method of accessing a version of a row in a temporal database, comprising:

checking at least a timestamp associated with the version of the row against a lock criteria for the row version;

based on a result of the checking step, determining whether to access the version of the row; and

accessing the version of the row without acquiring a lock for the row.

2. The method of claim 1, wherein:

the lock criteria for the row version is a time range lock period for the row.

3. The method of claim 1, wherein:

the timestamp includes a starting period time stamp for the row version.

4. The method of claim 3, wherein:

the time lock criteria for the row version is a time range lock period for the row; and

checking at least a timestamp associated with the version of the row against a time criteria for the row includes checking whether the starting period timestamp for the row version is prior to the time range lock period.

5. The method of claim 2, wherein:

checking against the time range lock period for the row includes checking whether a starting period timestamp associated with the row version is outside the time range lock period.

6. The method of claim 5, wherein:

an ending period timestamp for the row version is treated as being an ending period of the time range lock period if the ending period timestamp of the row version is greater than the start of the time range lock period for the row.

7. The method of claim 1, wherein:

the row version is being accessed from a current branch, and

the lock criteria for the row version includes lock criteria associated with a branch, other than the current branch, from which the row version is inherited.

8. The method of claim 7, wherein:

the time criteria associated with the branch from which the row version is inherited includes a lock ceiling associated with the branch from which the row version is inherited.

9. The method of claim 7, wherein:

the branch from which the row version is inherited is an ancestor branch to the current branch, and

the row version has been created by the ancestor branch prior to the branch floor of the current branch.

10. The method of claim 9, wherein:

there is at least one intermediate branch between the current branch and the branch from which the row version is inherited; and

the row version has additionally been created prior to the branch floor of each of the at least one intermediate branch.

11. A method of configuring a temporal database, comprising:

providing a table for time-range lock definitions associated with rows of the database; and

for each application table in the database that uses primary keys;

providing at least one column of the application table configured for characterizing, for each row version for each primary key, a time range associated with that row version; and

providing a primary key constraint on the application table that allows, for each row, duplicate primary key values for versions of that row characterized by non-overlapping time ranges.

12. The method of claim 11, further comprising:

providing a foreign key to associate a time-range lock with a branch.

providing a foreign key column to associate each row version with a branch;

providing a primary key constraint on the table that allows, for each row, duplicate primary key values for that row for versions of that row characterized by being in different branches.

13. A method of providing a new version of a row of a database, comprising:

posting a time-range lock for the row;

performing the update of the row within a time indicated by the time-range lock; and

committing the updates.

14. The method of claim 13, wherein:

posting the time-range lock for the row includes making the time-range lock visible to readers of the row.

15. The method of claim 13, wherein:

if the new version of the row is in a child branch of the database, and the time-range lock is characterized by a starting timestamp older than a floor of the child branch, not accepting for posting the time-range lock for the row.

16. The method of claim 14, wherein:

posting the time range lock for the row includes posting a time range lock for a branch to which the version of the row belongs.