A super column family is a NoSQL object that contains column families. It is a

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(pair) that consists of a key–value pair, where the key is mapped to a value that are column families. In analogy with relational databases, a super column family is something like a "view" on a number of tables. It can also be seen as a map of tables.

Benefits

It is useful when making a data model to have some kind of a view on a number of

tables Table may refer to: * Table (furniture), a piece of furniture with a flat surface and one or more legs * Table (landform), a flat area of land * Table (information), a data arrangement with rows and columns * Table (database), how the table d ...

. Using a super column family is something similar to that in

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s. There are, however, no "

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" between the "tables", as data stores like

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are non-relational.

Sorting and querying

There is no way to sort super columns after they have been inserted, nor to query an arbitrary query in

s. Super columns are sorted when they are added to the column family, and it is also possible to use a different sorting attribute for the contained

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of a super column. Similar to the standard column family, sorting is defined by an attribute. This attribute is called the CompareSubcolumnsWith in

and have the following values: * AsciiType * BytesType * LexicalUUIDType * LongType * TimeUUIDType * UTF8Type Although it is possible to sort the super columns in a way, the columns inside the super columns another way, it is not allowed to treat part of the super columns in a special way.

Super column families vs. views

Column families have a schemaless nature so that each of their "row"s can contain a different number of columns, and even different column names could be in each row. So, they are a very different concept than the rows in relational database management system (RDBMS)s. This is one of the reasons why the concept is not trivial for an experienced RDBMS expert.

Code example

Here is an example of a super column family that contains other column families: UserList= Where "Cath" and "Terry" are row keys; "username", "address", and "account" are super column names; and "firstname", "lastname", "city", etc. are column names.

References

External links