| 摘要 |
<p>The present invention provides the ability to alter data definitions in a Database Management System (DBMS). The present invention provides the ability to maintain DBMS and application catalogs. Alterations can be made to the application catalog (106), and the changes propagated to the DBMS catalog (102) based on the differences between like information in the application and DBMS catalogs as identifed by the present invention. The present invention provides the ability to test for data loss. That is, the present invention examines the requested alteration and the data that will be affected by the alteration to determine whether or not the alteration will result in the loss of data. If loss of data is possible, alerts can be generated to determine whether or not to proceed with the alterations. The present invention provides two techniques to perform the alterations depending on the ability of the DBMS to perform an alter on the original table without using an intermediate table (i.e., a native alter), or performing the alterations using an intermediate table for a DBMS with limited native alter capabilities.</p> |
