Apparatus and method for database migration

• US 20050149537A1
• Filed: 09/27/2004
• Published: 07/07/2005
• Est. Priority Date: 09/26/2003
• Status: Active Grant

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Microsoft Corporation
• Inventors: Balin, Irena, Balin, Dmitry, Bekelman, Igor
• Granted Patent: US 7,664,795 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G06F 16/214 Database migration support

Abstract

Systems and methods consistent with concepts of the present embodiment of the inventive concept provide mechanisms for database migration from one database (source database platform) platform to another (target database platform). The target and source databases can be any relational databases including, without limitation, Oracle, SQL Server (Microsoft), DB2 UDB (IBM), Sybase, MySQL, PostgreSQL, and the like. The inventive methodology will work well for migration of any relational database that implements SQL language from one platform to another. A feature of the invention is the provision of a virtual engine enabling the running of an original application on a migrated database.

Claims

1. A method for migrating a database from a source database platform to a target database platform, said method comprising:

(a) creating and loading into a memory a source meta-database, wherein said meta-database is presented in the form of a tree and represents the essence of a data model of said database;

(b) converting the schema of said database by migrating the source database objects into the destination ones, wherein during said conversion the objects can change their parameters, number of fields, or structure because of the inconsistency in the data types in source and destination databases;

(c) extracting the SQL code of the stored procedures;

(d) parsing the SQL code and presenting it in the internal tree structure, wherein declaration point reference are setup for local identifiers;

(e) converting of the parsed tree into the destination platform tree, wherein the tree is transformed appropriately to express the actual SQL code conversion;

(f) generating a script using the converted schema tree, wherein said script is loaded to create the target database objects; and

(g) loading the converted SQL stored procedures into previously converted target database.

2. The method of claim 1, wherein when a source object structure does not have a corresponding target object structure, the source object is emulated in the converted target database in the form of a table.

3. The method of claim 1, further comprising implementing a converter wrapper on a driver of said converted target database.

4. The method of claim 3, wherein said converter wrapper comprises a cache having entries of source calls and corresponding converted calls.

5. The method of claim 4, wherein when a new call is received, the converter wrapper queries the cache to determine whether such a call is stored in the cache and:

if so, the converter fetches the corresponding converted call;

if not, the converter converts the new call into a new converted call and stores in the cache the new call and the new converted call.

6. The method of claim 5, wherein the converter wrapper sends the converted call or the new converted call to the converted target database.

7. The method of claim 5, wherein the converter wrapper sends the converted call or the new converted call to said driver.

8. The method of claim 6, further comprising a virtual database server interposed between said driver and said converted target database.

9. The method of claim 8, wherein said converter wrapper comprises a plurality of meta-databases.

15. The method of claim 8, wherein said software wrapper comprises a plurality of meta-databases.

10. A method of converting source SQL calls from source SQL dialect to target SQL calls for a target SQL dialect, without significant changes in application code, said method comprising:

(a) creating and loading into memory a source meta-database, wherein said meta-database is presented in the form of a tree and represents the essence of a data model of a target database;

(b) creating a software wrapper over a database driver, said software wrapper receiving said source SQL calls from said database driver and providing a corresponding target SQL calls, said software wrapper further storing in memory the source SQL calls and target SQL calls.

11. The method of claim 10, wherein when a source SQL call is received, the software wrapper queries the memory to determine whether such a source SQL call is stored in the memory and:

if so, the software converter fetches the corresponding target SQL call;

if not, the software converter converts the source SQL call into a target SQL call and stores in the memory source SQL call and the target SQL call.

12. The method of claim 11, wherein the software wrapper sends the target SQL call to the target database.

13. The method of claim 11, wherein the software wrapper sends the target SQL call to said driver.

14. The method of claim 11, further comprising a virtual database server interposed between said driver and said target database.

16. A database virtualization middleware, allowing a source client application implemented to run against a source database on a source platform to run against a target database on a target platform different from the source platform, comprising:

an SQL Converter engine;

an SQL Converter memory;

at least one meta-database component storing logical representation of the target database;

a database driver interface.

17. The database visualization middleware of claim 16, further comprising an emulator emulating said target database to the client application.

18. The database visualization middleware of claim 16, comprising a plurality of meta-databases storing logical representation of corresponding target databases.

19. The database visualization middleware of claim 16, wherein calls issued by the client application are sent to said SQL converter engine from an application driver and calls converted by said SQL converter are sent to said target database.

20. The database visualization middleware of claim 16, wherein calls issued by the client application are sent to said SQL converter engine from an application driver and calls converted by said SQL converter are sent to back to said application driver.