The Salesforce Migration example job has been derived from the standard Talend Framework Template Jobs in the usual manner. If you are not familiar with creating jobs from templates, then take the opportunity to read the tutorial My First Framework Job.
This example Job may be used as a template for any data migration, including your own Salesforce data migration, regardless of your source or target vendors.
There is nothing unusual to SalesforceMigrate and SalesforceMigrateProcess, to what you would see with any other Talend Framework job. It is with SalesforceMigrateOrchestrate that you will start to see the structure of jobs that have been tailored for the purpose of data migration.
As you may imagine with a complex requirement such as data migration, you will be creating a number of child jobs, each performing specific tasks.
For anything but the most trivial of tasks, it is recommended that you create jobs whose sole purpose is for the orchestration of other jobs, that is, to manage the execution of a series of jobs that are to be executed either sequentially of in parallel.
In this Data Migration Framework, SalesforceMigrateOrchestrate is the first of our orchestration jobs.
Parallel job execution is outside the scope of this tutorial. All of the jobs and data flows within this tutorial are executed sequentially, with the exception of loading data in to Salesforce, where Salesforce may manage the parallel loading of data.