Adaptive relational database access

• US 8,335,804 B2
• Filed: 03/29/2010
• Issued: 12/18/2012
• Est. Priority Date: 03/29/2010
• Status: Expired due to Fees

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Catterall, Roy Antony, Chandler, Allan Thomas, Place, Alan David, Shewell, Mark Andrew, Yates, Stephen James
• Primary Examiner(s): Alam, Shahid
• Assistant Examiner(s): Bullock, Joshua
• Application Number:
  US12/748,943
• Publication Number:
  US 20110238642A1
• Time in Patent Office: 995 Days
• Field of Search: 707/705, 707802-803
• US Class Current: 707/803
• CPC Class Codes: G06F 16/20 of structured data, e.g. relational data
• CPC Class Codes: G06F 16/213 with details for schema evolution support

Abstract

An approach is provided that receives an alteration request to mark a selected column in a database table as an unused column. A database control table is then updated to indicate that the selected column is unused. After the database control table is updated, when a read request is received for the selected column, the same data is returned for the selected column for each row being read and this data is not stored in the database table.

Claims

1. A machine-implemented method comprising:

receiving an alteration request to mark a selected column in a database table as an unused column;

updating a database control table indicating that the selected column is unused;

after the database control table is updated, returning data not stored in the selected column in response to a read request corresponding to the selected column;

retrieving a write value associated with the alteration request;

storing the write value in the control table;

receiving a write request corresponding to the selected column from a calling routine, wherein the write request includes write data and identifies one or more rows to write to the database table; and

in response to receiving the write request, retrieving the previously stored write value, and writing the previously stored write value to the selected column of the one or more rows, wherein the write data included in the write request is not written to the selected column of the one or more rows.

2. The method of claim 1 further comprising:

retrieving a get value associated with the alteration request; and

storing the get value in the control table.

3. The method of claim 2 further comprising:

receiving the read request corresponding to the selected column from a calling routine;

determining that the selected column is unused by checking the control table;

retrieving the get value from the control table in response to the determination; and

returning the get value to the calling routine.

4. The method of claim 1 wherein the write value includes a change value and a put value, and further comprising:

in response to receiving the write request, identifying whether the one or more rows currently exist in the database table; and

in response to the one or more rows currently existing in the database table;

passing the change value to the write logic so that the change value is written to the selected column of the one or more rows.

5. The method of claim 1 wherein the write value includes a change value and a put value, and further comprising:

in response to receiving the write request, identifying whether the one or more rows currently exist in the database table; and

in response to the one or more rows not currently existing in the database table;

passing the put value to the write logic so that the put value is written to the selected column of the one or more rows.

6. The method of claim 1 wherein the write value includes a change value and a put value, and further comprising:

in response to receiving the write request, identifying whether the one or more rows currently exist in the database table; and

in response to the one or more rows currently existing in the database table and the change value indicating that the change value is “

as is”

;

inhibiting writing of any data to the selected column of the one or more rows.

7. The method of claim 1 further comprising:

receiving a second alteration request to mark the selected column in the database table as a used column;

updating the database control table indicating that the selected column is used;

after the database control table is updated to indicate that the selected column is used;

receiving a subsequent read request to read a first set of one or more rows;

retrieving a data stored in the selected column from the database table at the first set of rows;

receiving a subsequent write request to write a provided data to a second set of one or more rows; and

writing the provided data to the selected column in the database table at the second set of rows.

8. An information handling system comprising:

one or more processors;

a memory accessible by at least one of the processors;

a nonvolatile storage medium accessible by at least one of the processors;

a database management system including a set of instructions stored in the memory and executed by at least one of the processors in order to perform actions of;

receiving an alteration request to mark a selected column in a database table as an unused column;

updating a database control table indicating that the selected column is unused;

after the database control table is updated, returning data not stored in the selected column in response to a read request corresponding to the selected column;

retrieving a write value associated with the alteration request;

storing the write value in the control table;

receiving a write request corresponding to the selected column from a calling routine, wherein the write request includes write data and identifies one or more rows to write to the database table; and

in response to receiving the write request, retrieving the previously stored write value, and writing the previously stored write value to the selected column of the one or more rows, wherein the write data included in the write request is not written to the selected column of the one or more rows.

9. The information handling system of claim 8 wherein the actions further comprise:

retrieving a get value associated with the alteration request; and

storing the get value in the control table.

10. The information handling system of claim 9 wherein the actions further comprise:

receiving the read request corresponding to the selected column from a calling routine;

determining that the selected column is unused by checking the control table;

retrieving the get value from the control table in response to the determination; and

returning the get value to the calling routine.

11. The information handling system of claim 8 wherein the write value includes a change value and a put value, and wherein the actions further comprise:

in response to receiving the write request, identifying whether the one or more rows currently exist in the database table; and

in response to the one or more rows currently existing in the database table;

passing the change value to the write logic so that the change value is written to the selected column of the one or more rows.

12. The information handling system of claim 8 wherein the write value includes a change value and a put value, and wherein the actions further comprise:

in response to receiving the write request, identifying whether the one or more rows currently exist in the database table; and

in response to the one or more rows not currently existing in the database table;

passing the put value to the write logic so that the put value is written to the selected column of the one or more rows.

13. The information handling system of claim 8 wherein the actions further comprise:

receiving a second alteration request to mark the selected column in the database table as a used column;

updating the database control table indicating that the selected column is used;

after the database control table is updated to indicate that the selected column is used;

receiving a subsequent read request to read a first set of one or more rows;

retrieving a data stored in the selected column from the database table at the first set of rows;

receiving a subsequent write request to write a provided data to a second set of one or more rows; and

writing the provided data to the selected column in the database table at the second set of rows.

14. A computer program product comprising:

a computer memory;

first program instructions to receive an alteration request to mark a selected column in a database table as an unused column;

second program instructions to update a database control table indicating that the selected column is unused;

third program instructions to, after the database control table is updated, return data not stored in the selected column in response to a read request corresponding to the selected column;

fourth program instructions to retrieve a write value associated with the alteration request;

fifth program instructions to store the write value in the control table;

sixth program instructions to receive a write request corresponding to the selected column from a calling routine, wherein the write request includes write data and identifies one or more rows to write to the database table;

seventh program instructions to, in response to receiving the write request, retrieve the previously stored write value, and write the previously stored write value to the selected column of the one or more rows, wherein the write data included in the write request is not written to the selected column of the one or more rows; and

wherein the first, second, third, fourth, fifth, sixth, and seventh program instructions are stored on the computer memory.

15. The computer program product of claim 14 further comprising:

eighth program instructions to retrieve a get value associated with the alteration request;

ninth program instruction to store the get value in the control table; and

wherein the eighth and ninth program instructions are stored on the computer memory.

16. The computer program product of claim 15 further comprising:

tenth program instructions to receive the read request corresponding to the selected column from a calling routine;

eleventh program instructions to determine that the selected column is unused by checking the control table;

twelfth program instructions to retrieve the get value from the control table in response to the determination;

thirteenth program instructions to return the get value to the calling routine; and

wherein the tenth, eleventh, twelfth, and thirteenth program instructions are stored on the computer memory.

17. The computer program product of claim 14 wherein the write value includes a change value and a put value, and further comprising:

fourteenth program instructions to, in response to receiving the write request, identify whether the one or more rows currently exist in the database table;

fifteenth program instructions to, in response to the one or more rows currently existing in the database table, to pass the change value to the write logic so that the change value is written to the selected column of the one or more rows; and

wherein the fourteenth and fifteenth program instructions are stored on the computer memory.

18. The computer program product of claim 14 wherein the write value includes a change value and a put value, and further comprising:

sixteenth program instructions to, in response to receiving the write request, identify whether the one or more rows currently exist in the database table;

seventeenth program instructions to, in response to the one or more rows not currently existing in the database table, pass the put value to the write logic so that the put value is written to the selected column of the one or more rows; and

wherein the sixteenth and seventeenth program instructions are stored on the computer memory.

19. The computer program product of claim 14 further comprising:

eighteenth program instructions to receive a second alteration request to mark the selected column in the database table as a used column;

nineteenth program instructions to update the database control table indicating that the selected column is used;

twentieth program instructions to receive a subsequent read request to read a first set of one or more rows;

twenty-first program instructions to retrieve a data stored in the selected column from the database table at the first set of rows;

twenty-second program instructions to receive a subsequent write request to write a provided data to a second set of one or more rows;

twenty-third program instructions to write the provided data to the selected column in the database table at the second set of rows; and

wherein the eighteenth, nineteenth, twentieth, twenty-first, twenty-second, and twenty-third program instructions are stored on the computer memory.