A method for managing event-condition-action rules in a database system comprising one or more database servers, the method comprising the computer-implemented steps of: the database system receiving one or more database query language statements that specify an event-condition-action rule pertaining to a composite event structure that is associated with a plurality of primitive events, the event-condition-action rule comprising: a set of one or more conditions against which said primitive events associated with said composite event structure are evaluated, and one or more action preferences to be used for determining a corresponding action to be performed in response to occurrence of a composite event that (i) comprises the primitive events associated with said composite event structure and (ii) satisfies said set of one or more conditions, wherein at least one condition of the set of one or more conditions refers to information stored in at least two different tables within said database system; storing said event-condition-action rule within said database system; during a database session at said one or more database servers of said database system, said one or more database servers incrementally evaluating the one or more conditions of said set of one or more conditions as one or more of the primitive events occur, the incremental evaluation comprising, for each primitive event occurrence associated with the composite event structure, performing: detecting the occurrence of a primitive event that is associated with said composite event structure, and determining whether said occurrence of said primitive event satisfies any condition of said set of one or more conditions, wherein results of said determining for each primitive event are persistently stored in a database within said database system; and if said occurrence of said primitive events associated with the composite event structure has been detected and it has been determined that said set of one or more conditions are satisfied, then the one or more database servers performing the corresponding action within the database system or causing performance of the corresponding action outside of the database system. the database system receiving one or more database query language statements that specify an event-condition-action rule pertaining to a composite event structure that is associated with a plurality of primitive events, the event-condition-action rule comprising: a set of one or more conditions against which said primitive events associated with said composite event structure are evaluated, and one or more action preferences to be used for determining a corresponding action to be performed in response to occurrence of a composite event that (i) comprises the primitive events associated with said composite event structure and (ii) satisfies said set of one or more conditions, wherein at least one condition of the set of one or more conditions refers to information stored in at least two different tables within said database system; a set of one or more conditions against which said primitive events associated with said composite event structure are evaluated, and one or more action preferences to be used for determining a corresponding action to be performed in response to occurrence of a composite event that (i) comprises the primitive events associated with said composite event structure and (ii) satisfies said set of one or more conditions, wherein at least one condition of the set of one or more conditions refers to information stored in at least two different tables within said database system; storing said event-condition-action rule within said database system; during a database session at said one or more database servers of said database system, said one or more database servers incrementally evaluating the one or more conditions of said set of one or more conditions as one or more of the primitive events occur, the incremental evaluation comprising, for each primitive event occurrence associated with the composite event structure, performing: detecting the occurrence of a primitive event that is associated with said composite event structure, and determining whether said occurrence of said primitive event satisfies any condition of said set of one or more conditions, wherein results of said determining for each primitive event are persistently stored in a database within said database system; and detecting the occurrence of a primitive event that is associated with said composite event structure, and determining whether said occurrence of said primitive event satisfies any condition of said set of one or more conditions, wherein results of said determining for each primitive event are persistently stored in a database within said database system; and if said occurrence of said primitive events associated with the composite event structure has been detected and it has been determined that said set of one or more conditions are satisfied, then the one or more database servers performing the corresponding action within the database system or causing performance of the corresponding action outside of the database system.