1. Give a description in your own words of the ACID properties of a transaction.
ACID (atomicity, consistency, isolation, durability) is a set of properties that guarantee that database transactions are processed reliably. This really refers to what can be described of a single logical operation called transaction. For example, in a sql server database, I may choose to update a customer records in two tables. Usually, I would update the record in one table first followed by the next table. But it may result in such that only one table is updated due to some errors. Using transaction, it would mean that either both the table is updated or none is updated. Once the transaction is completed, the database will be in a consistent state and the changes made by the transaction is permanently stored in the database.
2. Describe a TP monitor environment. How can a TP monitor stop an operating system being overwhelmed?
A TP monitor is a control program that manages the transfer of data between multiple local and remote terminals and the application programs that serve them. It provides integrity by making sure that transactions do not get lost. It has the ability to update multiple different databases in a single transaction and has the ability to attach priority to transactions and provide security.
With the TP monitor technology, a client connects to the TP monitor instead of the database server. The TP monitor accepts the transaction, queues it and manages it till completion. This helps the operating system from being overwhelmed.
References:
http://en.wikipedia.org/wiki/ACID
http://www.peterindia.net/N-tierApplicationsView.html
ACID (atomicity, consistency, isolation, durability) is a set of properties that guarantee that database transactions are processed reliably. This really refers to what can be described of a single logical operation called transaction. For example, in a sql server database, I may choose to update a customer records in two tables. Usually, I would update the record in one table first followed by the next table. But it may result in such that only one table is updated due to some errors. Using transaction, it would mean that either both the table is updated or none is updated. Once the transaction is completed, the database will be in a consistent state and the changes made by the transaction is permanently stored in the database.
2. Describe a TP monitor environment. How can a TP monitor stop an operating system being overwhelmed?
A TP monitor is a control program that manages the transfer of data between multiple local and remote terminals and the application programs that serve them. It provides integrity by making sure that transactions do not get lost. It has the ability to update multiple different databases in a single transaction and has the ability to attach priority to transactions and provide security.
With the TP monitor technology, a client connects to the TP monitor instead of the database server. The TP monitor accepts the transaction, queues it and manages it till completion. This helps the operating system from being overwhelmed.
References:
http://en.wikipedia.org/wiki/ACID
http://www.peterindia.net/N-tierApplicationsView.html
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