A system and method for querying a database is disclosed. Database tables are represented as nodes in a model. Each node is associated with at least one leaf. The nodes can be interconnected with one another. A model input is received by a server from a client device, the model input including a starting node, one or more leaves, and optionally one or more filters. A query is executed against a database based on the model input. A subsequent query can be generated by selecting a result of the first query. Also disclosed is a technique for cancelling queries.