Super column
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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 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:
{
"databases": {
"Cassandra": {
"age": 20,
"name": {
"firstName": "Cassandra",
"lastName": "apache"
}
},
"HBase": {
"age": 20,
"address": {
"city": "Seoul",
"postcode": "1234"
}
}
}
}Where:
"databases" are keyspace;
"Cassandra" and "HBase" are rowKeys;
"name" and "address" are super column names;
"firstName", "city", "age", etc. are column names.
See also
References
- ↑ Sarkissian, Arin (September 1, 2009). "WTF is a SuperColumn". http://arin.me/post/40054651676/wtf-is-a-supercolumn-cassandra-data-model. Retrieved October 28, 2017. "A SuperColumn is a tuple w/ a binary name & a value which is a map containing an unbounded number of Columns - keyed by the Column’s name."
- ↑ Ellis, Jonathan (August 15, 2016). "Data Model". https://wiki.apache.org/cassandra/DataModel. Retrieved October 28, 2017.
External links
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