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From sonia gehlot <sonia.geh...@gmail.com>
Subject Cassandra basics
Date Fri, 23 Jul 2010 22:48:12 GMT
Hi Guys,

Recently I have started reading about Cassandra from the material available
on net. But I have very confused with the basic understanding of Cassandra.
I understand columnFamilies, supper columnFamilies but I have no clear
understanding of

<Keyspace Name="Twitter">
  <ColumnFamily CompareWith="UTF8Type" Name="Statuses" />
  <ColumnFamily CompareWith="UTF8Type" Name="StatusAudits" />

  <ColumnFamily CompareWith="UTF8Type" Name="StatusRelationships"
CompareSubcolumnsWith="TimeUUIDType" ColumnType="Super" />
  <ColumnFamily CompareWith="UTF8Type" Name="Users" />

  <ColumnFamily CompareWith="UTF8Type" Name="UserRelationships"
CompareSubcolumnsWith="TimeUUIDType" ColumnType="Super" />
</Keyspace>


<ColumnFamily Name = "LocationUserIndexSCF"
         CompareWith = "UTF8Types"
         CompareSubcolumnsWith= "UTF8Type"
         ColumnType = "Super"/>

1. I don't understand what is this *"CompareWith", "CompareSuperColumnWith",
"CompareSubcolumnsWith"* etc is?

2. What is *"UTF8Type", "TimeUUIDType", "LongType", "ASCIIType" *etc.. is
these are datatypes? as we have datatype in SQL, if so then is this is
datatype of value stored in this column family?



May be I am getting confused because I am mixing my Relational databases
fundamentals with distributed.
Please If someone can explain me significance of these things then it would
be very helpful.

Thanks in advance.

Please reply.

Sonia

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