some doubts regarding 0CDS_DS01 and 0CDS_DS02

hi all:

I have some doubts regarding 0CDS_DS01 and 0CDS_DS02?

As we know , Schedule Lines for Sales Scheduling Agreements is for 0CDS_DS01

Sales Scheduling Agreement Items is for 0CDS_DS02 ,

the data of 0CDS_DS02 can only be filled with data about sales scheduling agreement items that are also planned in SAP APO.

it seems that 0CDS_DS01 is also from APO,

what is the difference between Schedule Lines and items ?

thank you very much