by David H
This article talks about using core component of database to design multi database system through software development approach. The core of components that design multi databases includes three interfaces. They are User, Administrators, and Database Handler interface. Each of interfaces has control accessing function. For instance, “User interface is starting point access for Core component. The administrators interface deal with access control privileges for users and local databases. Database Handler facilitates global schema management and site management.” In addition, this article also talks about how Database handler performs each component of database. There are four sub components that are in Database handler which are Schema Manager, Site Manager, Execution Manager, and Assertion. Basically, what Schema Manager does is use multiple databases and store it to Global Schema. In addition, Schema Manager does verify the query. If it sees the error or has the same name, it will resolve it by using explicit translation process. Site Manager construct by five sub components. They are Site Handler, Fragmentation Manager, Replication Manager, Failure Management, and Schema Map. Execution Manager provides interface and checks the pre-condition. These sub components carry a specific task to database. Assertion Manager uses precondition for user input and post-condition for all of the following: connection, errors type, and log files of query.
This article relates to class because it talks about some of components of database environment that we were discussing chapter 1 in class last Monday. In this article, it talked about three components instead of nine components that we were discussing on the class. This article helps me have a better understanding of how these components build up by using, what Dr. Muthaiyan calls, distributive multi-database system. In addition, I have learned that each sub component in Database Handler is a crucial part of the system which is how they implement and execute data.
Moreover, I have learned that in Algorithm Precondition, we use “and, or, not” for logic condition. To do so, we write the code using SQL. On the other hand post-condition, it checks condition first and then if it qualifies the precondition, it will execute. This article is interesting and very helpful.
Muthaiyan, M. , Balakrishnan, V. , & Seenivasan, S. (2010). Component approach to software development for distributed multi-database system. Informatica Economica,14(2), 19-26.