How Delta import and Delta sync work for GALMA,ADMA,LDIFMA,OracleMA ?

We use MIIS for galsync.

I heard that anchor value of GALMA,ADMA is objectGUID.

Q1

I guessed that during Delta import GALMA,ADMA use objectGUID to like data source and CS object and compare object update time and if object update time are different , they are imported to CS object.

Q2

But how about SQLMA,LDIFMA,OracleMA ,AVPMA ,etc?

There is anchor setting for those MAs but, how MIIS and FIM detect data source change other than anchor attribute ?

Q3

About Delta sync I guessed that it compare CS object anchor and update time with Metaverse object and they are different , MV object are updated.

Is that correct ?