In the last decade, the term instance-spanning constraint has been introduced in the process mining field to refer to constraints that span multiple process instances of one or several processes. Of particular relevance, in this setting, is checking whether process executions comply with constraints of interest, which at runtime calls for suitable monitoring techniques. Even though event data are often stored in some sort of database, there is a lack of database-oriented approaches to tackle compliance checking and monitoring of (instance-spanning) constraints. In this paper, we fill this gap by showing how well-established technology from database query processing can be effectively used for this purpose. We propose to define an instance-spanning constraint through an ensemble of four database queries that retrieve the satisfying, violating, pending-satisfying, and pending-violating cases of the constraint. In this context, the problem of compliance monitoring then becomes an application of techniques for incremental view maintenance, which is well-developed in database query processing. In this paper, we argue for our approach in detail, and, as a proof of concept, present an experimental validation using the DBToaster incremental database query engine.