>>>>>Speaking about Maintenance plan. Who makes it (if such term can apply to it)? the DBA or developer?
>>>>
>>>>DBA of course.
>>>>That is their job to Maintenance the databases.
>>>
>>>Thank you. I am sorry that I am asking so many questions. But what does a developer tell the DBA? That is, should the developer provide some kind of paper documentation describing what tables or what indexes it should have?
>>
>>Developer can propose a table schema (with indexes) to a DBA and DBA then will implement it (and may improve).
>>
>>But actually the process of DBA and Developers communications may vary from organization to organization.
>
>Thank you. I am just trying to fake it to the DBA as if I know what I am doing :)

Do you want to have a separate database for your application or you're adding something to existing database?

In the first case, create database diagram also as part of the documentation of proposed database. In the second case, you can also use DB diagram, but will need to select just newly created objects.