document oriented mapReduce databases - schema and queries

paweł kamiński kamiseq@REDACTED
Thu Jul 2 11:47:02 CEST 2009

hi, all
recently I ve started to look at couchDB and what I see sounds great but I
have few general questions

1)when it is better to use MR db and not RDMS (I have structurised documents
split into tables)
2)why schema free is good, how then ensure that what somebody puts to db is
what it should be especially when JSON can handle any data type and it is
easy to make a mistake
3)as a old SQL developer Im force now to think how to implement all map and
reduce function to make them efficient. with select statement I just write
what I want and leave all to the system.
4)how to design my db, curently my db is about 500 master to items tables,
so I understand how to aggragate with MR but how to join and how to make it
work fast and use as small disk as possible and that data are not redundant.
5)If my RDBS is running on 2core (ore sometimes one core) machine, and that
machine is alone server storing data from local clients is there any gain of
using systems such as couchDB or others (ok replication and other features
are still nice)
6)this is somehow related to point 5) what scale down really means (to work
on mobiles, browsers etc)? If I have one core machine then will the system
be fast enough than RDMS (sqlite)

thanks for helping me in that

Paweł Kamiński


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