Sunday, April 14, 2013

Associative array



  • Associative array

In computer science, an associative array, map, or dictionary is an abstract data type composed of a collection of  pairs, such that each possible key appears at most once in the collection.

The dictionary problem is the task of designing a data structure that implements an associative array. A standard solution to the dictionary problem is a hash table; in some cases it is also possible to solve the problem using directly addressed arrays, binary search trees, or other more specialized structures

Associative arrays have many applications including such fundamental programming patterns as memoization and the decorator pattern.

http://en.wikipedia.org/wiki/Associative_array

What is MultiValue Database?



  • What is MultiValue Database?

MultiValue is a type of NoSQL and multidimensional database, typically considered synonymous with PICK, a database originally developed as the Pick operating system.
These databases differ from a relational database in that they have features that support and encourage the use of attributes which can take a list of values, rather than all attributes being single-valued.
Unlike SQL-DBMS tools, most MultiValue databases can be accessed both with or without SQL.

Data model example
In a MultiValue database system:
a Database is called an "Account"
a Table is called a "file"
a Column is an "Attribute" or "Dictionary": attributes generally point at raw data, while dictionaries apply some transformation to the raw data

For example, assume there's a file (table) called "PERSON". And in this file there is a Dictionary (column) called "eMailAddress". The eMailAddress field can store a variable number of email address values in the single record.
So the list [joe@abc132.info, jdb@gbmail.net, joe_bacde@thisorthat.edu] can be stored and accessed via a single query / disk read when accessing the associated record.

To achieve the same (1-to-many) relationship within a Relational Database system one would be required to create an additional table to store the variable number of email Addresses associated to a single "PERSON" record.
http://en.wikipedia.org/wiki/MultiValue

jbase database


jbase database
jBase is a MultiValue Database software developed by jBASE International
http://www.jbase.com/

Matrix management


Matrix management
Matrix management is a type of organizational management in which people with similar skills are pooled for work assignments. For example, all engineers may be in one engineering department and report to an engineering manager, but these same engineers may be assigned to different projects and report to a different engineering manager or a project manager while working on that project. Therefore, each engineer may have to work under several managers to get his job done
http://en.wikipedia.org/wiki/Matrix_management