1. A computer-implemented method for invoking event handlers, the computer-implemented method comprising performing computer-implemented operations for: detecting an operation on application data associated with application metadata, the application data comprising a table having records, wherein the application data is published according to a publish and subscribe model, wherein the table includes references to one or more delegates comprising at least one of a pre-operation delegate or a post-operation delegate, and wherein one or more subscribers are notified if the operation on the application data is completed; in response to detecting the operation on the application data, determining if the application metadata comprises data describing one or more event handlers associated with the operation on the application data, wherein the one or more event handlers references one or more methods on a class; and in response to determining that the application metadata comprises the data describing the one or more event handlers, identifying the one or more event handlers and invoking the one or more event handlers, wherein invoking the one or more event handlers comprises, when the one or more event handlers comprise a plurality of event handlers, determining an order in which the plurality of event handlers are to be invoked, and invoking the plurality of event handlers in the order determined.