Enhanced high performance real-time relational database system and methods for using same
A database system supporting persistent queries, using an enhanced persistent query service and various data sources. On receiving a request to create a persistent query from a client software application, the persistent query service: creates a query virtual table; parses the persistent query; creates a plurality of intermediate virtual tables; establishes listeners for the query virtual table; creates a plurality of data source virtual tables; causes the plurality of data source virtual tables to retrieve initial data from data sources; and propagates data via intermediate virtual tables to the persistent query virtual table.
1. A database system supporting persistent queries, the system comprising:
a processor;
a memory;
a plurality of programming instructions stored in the memory and operating on the processor;
wherein, upon operating the programming instructions, the processor is configured to operate a persistent query service configured to receive connections and requests from client software applications;
wherein, on receiving a request from a client software application to create a persistent query from a client software application, the persistent query service:
creates a query virtual table corresponding to the persistent query;
parses the persistent query to create a tree structure representing a logical arrangement of a plurality of operators that yield results required by the persistent query;
creates a plurality of intermediate virtual tables corresponding to the plurality of operators, wherein the step of creating an intermediate virtual table further comprises establishing listeners associated with the intermediate virtual table to receive data change notifications;
establishes listeners for the query virtual table to receive data change notifications from a plurality of intermediate virtual tables;
creates a plurality of data source virtual tables, each corresponding to a specific data source required to fulfill the persistent query;
causes the plurality of data source virtual tables to retrieve initial data from the plurality of data sources; and
propagates data via the plurality of intermediate virtual tables and their associated listeners to the persistent query virtual table; and
wherein, on detection of a data change in a data source, the associated data source virtual table:
invokes a plurality of corresponding methods of listeners of a plurality of virtual intermediate tables;
propagates the data change to the persistent query virtual table;
updates a plurality of aggregations of data in tables when the data change is made against a table;
wherein the invocation, propagation, and updating steps are performed immediately as data changes occur in a real-time database, without compromising performance.
2. The system of claim 1 , wherein at least one intermediate virtual table is a projection table.
3. The system of claim 1 , wherein at least one intermediate virtual table is a group-by table.
4. The system of claim 1 , wherein at least one intermediate virtual table is an inner join table.
5. The system of claim 1 , wherein at least one intermediate virtual table is a filter table.
6. The system of claim 1 , further comprising a plurality of network interfaces.
7. The system of claim 6 , wherein the persistent query service is configured to receive queries from network-connected devices via a network interface.