Super column

The super column consists of a (unique) super column name, and a number of columns.

A super column is a tuple (a pair) with a binary super column name and a value that maps it to many columns.[1] They consist of a key-value pairs, where the values are columns. Theoretically speaking, super columns are (sorted) associative array of columns.[2] Similar to a regular column family where a row is a sorted map of column names and column values, a row in a super column family is a sorted map of super column names that maps to column names and column values.

A super column is part of a keyspace (data model) together with other super columns and column families, and columns.

Code example

Written in the JSON-like syntax, a super column definition can be like this:

 {
   "mccv": {
     "Tags": {
       "cassandra": {
         "incubator": {"url": "http://incubator.apache.org/cassandra/"},
         "jira": {"url": "http://issues.apache.org/jira/browse/CASSANDRA"}
       },
       "thrift": {
         "jira": {"url": "http://issues.apache.org/jira/browse/THRIFT"}
       }
     }
   }
 }

See also

References

  1. ↑ Arin Sarkissian (2009-09-01). "WTF is a SuperColumn? An Intro to the Cassandra Data Model". http://arin.me/post/40054651676/wtf-is-a-supercolumn-cassandra-data-model: Arin Sarkissian. A SuperColumn is a tuple with a binary name & a value which is a map containing an unbounded number of Columns – keyed by the Column‘s name.
  2. ↑ "Cassandra wiki: Data Model: Super columns". http://wiki.apache.org/cassandra/DataModel: Apache Cassandra. Retrieved 2011-03-18.

External links


This article is issued from Wikipedia - version of the 5/19/2016. The text is available under the Creative Commons Attribution/Share Alike but additional terms may apply for the media files.