API stands for Application programming interface is very useful in cloud platforms as it allows easy implementation of it on the system. It removes the need to write full fledged programs. It provides the instructions to make the communication between one or more applications. It also allows easy to create application with ease and link the cloud services with other systems.

Cloud computing is a metaphor used for internet. It provides on-demand access to virtualized IT resources that can be shared by others or subscribed by you. It provides an easy way to provide configurable resources by taking it from a shared pool. The pool consists of networks, servers, storage, applications and services.

Cloud computing consists of 3 layers in the hierarchy and these are as follows:

1. Infrastructure as a Service (IaaS) provides cloud infrastructure in terms of hardware like memory, processor speed etc. 

2. Platform as a Service (PaaS) provides cloud application platform for the developers. 

3. Software as a Service (SaaS) provides cloud applications which are used by the user directly without installing anything on the system. The application remains on the cloud and it can be saved and edited in there only.

Data warehouse

- It is a decision support database system for the purpose of organizational needs. 

-It is non volatile, integrated and time variant collection of data

Operational Data Stage

- It is an integrated collection of information. 

-It can contain 90 days of information at maximum.

-ODS supports dynamic data.

-Daily loading is known as incremental load.

-When data is selected from source, selected records are loaded between timestamp of last load and the current time 

-The parameter that are passed to perform are last loaded date and current date

-The first parameter is the stored last run date is read through job parameters

-The second parameter is the current date

Sequence numbers can be generated in Datastage using certain routines. They are

-KeyMgtGetNextVal

-KeyMgtGetNextValConn

- A tool for designing Extraction, Transformation and Loading

- An ideal tool for data integration projects system migrations

- Importing, extracting and creating metadata are within these jobs

- Data stage allows scheduling, monitoring and running the jobs 

- Allows to administer the development and execution in a single environment

- Physical Data Integration is all about creating new system that replicates data from the source systems.

- This process is done to manage the data independent of the original system.

- Data Warehouse is the example of Physical Data Integration.

- The benefits of PDI include data version management, combination of data from various sources, like mainframes, flat files, databases.

- A separate system is needed for handling vast data volumes.