Patent ID: 7925665

Claim:
A computer-implemented method comprising: receiving a query at a front-end database server, wherein said query references data stored in a first backend database and a second backend database, and said query comprises a subquery referencing data stored in said first backend database; if said query cannot be executed, in its entirety, on said data stored in said first backend database, executing said subquery on said data stored in said first backend database, wherein said executing said subquery comprises pushing said subquery to said first backend database for execution, if said first backend database supports functions in said subquery and includes data referenced by said subquery, and pulling into said front-end database server data referenced by said subquery from said first backend database, if said first backend database does not support said functions in said subquery; storing a first set of results from execution of said subquery into a temporary table in said second backend database when a persist-subquery option is activated, when said second backend database supports a subquery predicate, and when there is a valid connection pool with a write permission to said second backend database; modifying said query to reference said temporary table, thereby generating a modified query; executing said modified query on data stored in said second backend database; and displaying results of said executed modified query.