Difference between 2-tier and 3-tier application

-
2-tier architecture:


In 2-tier, the application logic is either buried inside the User Interface on the client or within the database on the server (or both). With two tier client/server architectures (see Two Tier Software Architectures), the user system interface is usually located in the user's desktop environment and the database management services are usually in a server that is a more powerful machine that services many clients. Processing management is split between the user system interface environment and the database management server environment. The database management server provides stored procedures and triggers.

3-tier architecture :


In 3-tier, the application logic (or) process lives in the middle-tier, it is separated from the data and the user interface. 3-tier systems are more scalable, robust and flexible. In addition, they can integrate data from multiple sources. In the three tier architecture, a middle tier was added between the user system interface client environment and the database management server environment.

There are a variety of ways of implementing this middle tier, such as transaction processing monitors, message servers, or application servers. The middle tier can perform queuing, application execution, and database staging. For example, if the middle tier provides queuing, the client can deliver its request to the middle layer and disengage because the middle tier will access the data and return the answer to the client. In addition the middle layer adds scheduling and prioritization for work in progress. The three tier client/server architecture has been shown to improve performance for groups with a large number of users (in the thousands) and improves flexibility when compared to the two tier approach. Flexibility in partitioning can be a simple as "dragging and dropping" application code modules onto different computers in some three tier architectures. A limitation with three tier architectures is that the development environment is reportedly more difficult to use than the visually-oriented development of two tier applications.

The most basic type of three tier architecture has a middle layer consisting of Transaction Processing (TP) monitor technology. The TP monitor technology is a type of message queuing, transaction scheduling, and prioritization service where the client connects to the TP monitor (middle tier) instead of the database server. The transaction is accepted by the monitor, which queues it and then takes responsibility for managing it to completion, thus freeing up the client.


Comments

Post a Comment

Popular posts from this blog

ISTQB Mocktest 1

-
1. ___________ Testing will be performed by the people at client own locations (1M) A. Alpha testing B. Field testing C. Performance testing D. System testing 2. System testing should investigate (2M) A. Non-functional requirements only not Functional requirements B. Functional requirements only not non-functional requirements C. Non-functional requirements and Functional requirements D. Non-functional requirements or Functional requirements 3. Which is the non-functional testing (1M) A. Performance testing B. Unit testing C. Regression testing D. Sanity testing 4. Who is responsible for document all the issues, problems and open point that were identified during the review meeting (2M) A. Moderator B. Scribe C. Reviewers D. Author 5. What is the main purpose of Informal review (2M) A. Inexpensive way to get some benefit B. Find defects C. Learning, gaining understanding, effect finding D. Discuss, make decisions, solve technical problems 6. Purpo...
Read more

Cloud Byte 2 - Common AWS Services for Cloud Practitioner Certification (CCP)

-
CloudWatch - Focuses on the activity of AWS services and resources, reporting on their health and performance. You can collect & track metrics . You can use Amazon CloudWatch Logs to monitor, store, and access your log files from Amazon Elastic Compute Cloud (Amazon EC2) instances, AWS CloudTrail, Route 53, and other sources. CloudWatch Logs enables you to centralize the logs from all of your systems, applications, and AWS services that you use, in a single, highly scalable service. You can then easily view them, search them for specific error codes or patterns, filter them based on specific fields, or archive them securely for future analysis. By default, logs are kept indefinitely and never expire. You can adjust the retention policy for each log group, keeping the indefinite retention, or choosing a retention periods between 10 years and one day. CloudTrails – Who is doing what in AWS . It is a log of all actions that have taken place inside your AWS environment. AWS Cloud...
Read more

Equivalence Class Partitioning

-
ECP is a testcase design techniques that divides the input data into set of partitions of data from which test case can be derived. The thumb rule is that there should be at least one class for each of partitions. It is expected that each member of class will have same behavior in the system. In other way ECP method creates same set of Input/Output that are handled in the same way by the application. This method helps to reduce number of test cases as we create classes for of test data & test them accordingly. The test that results from the representative value for a class is said to be "equivalent" to the other values in the same class. If no errors were found in the test of the representative value, it is reasoned that all the other "equivalent" values wouldn't identify any errors either.   For ex. lets have a systesm which takes 2 integer value & add them.As we know that sum of two integer will always be a positive Integer so if we have to test w...
Read more