Designing Triggers with Trigger-By-Example

Abstract

Abstract. One of the obstacles that hinder database trigger systems from their wide deployment is the lack of tools that aid users in creating trigger rules. Similar to understanding and specifying database queries in SQL3, it is difficult to visualize the meaning of trigger rules. Furthermore, it is even more difficult to write trigger rules using such text-based trigger rule language as SQL3. In this paper, we propose TBE (Trigger-By-Example) to remedy such problems in writing trigger rules visually by using QBE (Query-By-Example) ideas. TBE is a visual trigger rule composition system that helps the users understand and specify active database triggers. TBE retains benefits of QBE while extending features to support triggers. Hence, TBE is a useful tool for novice users to create simple triggers in a visual and intuitive manner. Further, since TBE is designed to hide the details of underlying trigger systems from users, it can be used as a universal trigger interface.

Testing Database-Centric Applications for Causes of Database Deadlocks

“…Database triggers are stored procedures associated with certain operations on database objects (e.g., tables and rows) [6], [8], [30]. Triggers autonomously react to database events by evaluating a datadependent condition and by executing a reaction whenever the condition is satisfied [21]. In addition, engineers develop database plugins that are programming components written in general-purpose programming languages and invoked in response to events that occur within database engines [13].…”

Extending Trigger-by-Example Approach to Support Time Events

“…Authors in [5] have also recognized the problem (writing triggers efficiently in various database management systems) and have tried to find a solution. Hence, it is hard to build a solution that is general and applicable for all database management systems because they all differ.…”

“…Hence, it is hard to build a solution that is general and applicable for all database management systems because they all differ. As the solution of already mentioned problem an idea of QBE (Query By Example) was used in [5]. Although the SQL is very much in use, some other languages can be used as well in order to work with databases.…”

“…Instead of writing required triggers manually, a new graphical interface for writing triggers was developed and the approach was given a name Trigger-By-Example (TBE). The whole procedure is well described in [5] and some examples were given; the paper is very well written and structured and contains a lot of examples. transition table name> <old transition table name> <transition table name> <new transition table name> <transition table name> <transition table name> ::= <identifier> We are not going to explain the syntax in a detail, but just point out some most important parts.…”

“…If two columns contained the same variable, then their values should correspond (columnl=column2 in the SQL). A working example of QBE used in [5] is presented in Table 1.…”