public void setDatabases(DBAggregationQueryConfigurationEntry[] databases) {
        this.databases = databases;
    }
This class represents the JAXB bean for the query configuration which provide a link between RDBMS Event Table
functions and DB vendor-specific SQL syntax.
modules/siddhi-core/src/main/java/io/siddhi/core/aggregation/persistedaggregation/config/DBAggregationQueryConfiguration.java