ISTQB - Iterative Model

Iterative model is one part of the software development life cycle. There are so many models available for software development life cycle as we have seen all in last article. In Iteration model, initially implementation will be done as simple as possible and afterwards complexity of the product will be increased. Further features of the product will be introduced until the final deployment procedure will be taken place. We must say that iteration model itself describes that it will break the large product in very small iteration and each iteration will be developed perfectly.

In the initial level of iterative model, all requirement will not be specified. Here first of all specified requirements will be developed and it will be reviewed to identify further requirements and it will be discussed and implemented in next iteration. Iteration procedure will be started with the simple implementation and small set of requirement will be developed first and each iteration will be contain versions till whole product will be developed. Each iteration have well define time period for development, testing and deployment.

This model have an advantage that it accepts the changes in previous iteration too so in the middle of the development, changes and improvement will be accepted. Even more than one build cycle or iteration can be developed at same time. During each build cycle, Requirement analysis, Design, Development, Testing and Deployment procedure will be required. Each specific build release will add the functionalities to the previous build. This kind of process will be continued till the whole product will be developed and deployed on client site.

Verification & Validation procedures are followed in each build will make this model more successful. Testing procedure will be followed too which increased the quality of the software. Any critical bug can be identified in the middle of the development instead of last stage of development. Versions for each iterator will be managed properly.

Thus, Here we can understand that iteration cycle of this model will not be started with the full of requirement specification. It is started with the one part of the whole application or project. This will be reviewed and observed by the experts and then further requirements will be identified. This procedure will be repeated and every time new version will be of the iteration will be given. As Described in image design, development, testing and deployment steps will be repeated as per requirement or till the application will be built completely.

We can take an example of a portrait. Here first of all one picture will be decided then in first stage face will be drawn. After wards from face whole structure will be decided and then background will be confirmed. Just like this whole application will be built.

When to Use Iterative model:

1. When requirements will be define clearly and that will be understood perfectly with team then we can use this model.
2. 2. When project will be signed for long term and or it has so many requirements at that time we can use this model. Basically for big project we can use iterative model.
3. 3. When requirements for specific and required model are clear in big project then we can use this model and small requirement can be added later on as per need.

Advantage of Iterative Model:

1. Project Management can be done easily with the version system. Here we can define all required design in very early stage of the project which can leads the project successful.
2. Here in this model the project will be built step by step so we can get defects in early stage and we can resolved the same which improves the quality of product.
3. In this model we can spare more time on designing instead of preparing documents which identified the picture of whole product and we can discuss same with client and any improvement or changes is required in product then we can do it.

Disadvantages of Iterative Model:

1. In this model overlapping will not be accepted at any cost. Whole product will be not accepted by client if any mistake have been done and different version will be overlapped.
2. This model is not much cost effective. An organization will need more cost to maintain this project with the iterative methodology.