Changing metadata without invalidating cursors

摘要

A method and apparatus for changing versioned metadata without invalidating cursors is provided. Cursors may be linked to the appropriate version of metadata at execution time as opposed to compilation time, meaning that they do not require recompilation to link to a new version of metadata. A database system maintains compiled code implementing a plan with respect to data items in a data storage space. The compiled code may have been generated in response to receiving a request to perform an operation that may be implemented using the plan. A version of metadata is also maintained. The metadata describes characteristics of the data storage space implicated by the plan. The compiled code is executed. The step of execution comprises binding the compiled code to the version of metadata. A proxy object referenced in the compiled code may facilitate the binding of the compiled code to the appropriate version of metadata.