N

naïve Bayes classifier

A modeling technique where each attribute describes a class independent of any other attributes that also describe that class. SEE ALSO predictive modeling.

name

1. Generally, the designation of an object by a linguistic expression.
2. In data modeling, a class word, abbreviated usually to nm.

namespace

A defined domain within which a name is guaranteed to be unique and findable. A reusable reference glossary of XML attributes found at a URL address. Entity and attribute names used in XML documents can be easily qualified by associating them with namespaces identified by URL references.

naming convention

SEE naming standard.

naming standard

A pattern of assigning names, words, or parts of words to objects, often intended to convey meta-information that promotes consistency and ease-of-use while avoiding conflicts.

N-ary

Adjective. Relating to N (some number) of entities in a relationship, the number of attributes or columns in an entity table, the number of arguments or operands that a function requires, or more specifically, the number of objects in a predicate in ORM.

National Institute for Standards and Technology (NIST)

Formerly known as The National Bureau of Standards, a non-regulatory agency of the United States Department of Commerce. The institute's mission is to promote U.S. innovation and industrial competitiveness by advancing measurement science, standards, and technology in ways that enhance economic security and improve quality of life. As part of this mission, NIST awards the Malcolm Baldrige National Quality Award.

natural key

SEE key, business.

natural language modeling

The process of describing information using proper sentences, not abbreviations or sentence fragments.

near real time

Transmission with a minimal amount of propagation and buffering delays.

nearline storage

Data that is not on line but is capable of being accessed and placed on line within 15 seconds of the access request. Archived data may be kept in nearline storage. SEE ALSO archive.

nested query

SEE subquery.

nested relation

An attribute of a relation, itself representing a relation. In a relational DBMS, a column that contains a table in each row.

Net Present Value (NPV)

A comparison of the current value of a dollar versus the value of a dollar at some future time, after allowing for future influences such as inflation and expected rates of return. Positive NPV is said to indicate a good investment.

network

1. Visually, a graph of nodes and connections where more than one entry point for each node is allowed.
2. In architecture, a topological arrangement of hardware and connections to allow communication between nodes and access to shared data and software.

Network Configuration

Zachman Framework cell name, intersection of Where/Network Nodes and Component Assemblies/Technicians as Implementers.

network data model

SEE data model, network.

network database

SEE database, network.

Network Definition

Zachman Framework cell name, intersection of Where/Network Nodes and Business Concepts/Executive Leaders as Owners.

Network Definition Language (NDL)

Network Definition Language, the ANSI standard (first adopted in 1986) based on the CODASYL Network data structure. It was substantially rolled into the SQL:1999 ANSI standard, which is no longer relational.

Network File Share (NFS)

A folder (directory) on a server that is shared out to users on a local area network (LAN) or intranet. Users attach to this file share and can drag and drop files/folders or modify the files/folder within the file share. A file share is typically mapped to a user’s local computer as a logical drive, such as X:. It is accessed just like the other drives on your computer, such as the A: or C: drives. File shares are a fast and secure method for managing content on a remote server.

Network Identification

Zachman Framework cell name, intersection of Where/Network Nodes and Scope Contexts/Strategists as Theorists.

Network Instantiation

Zachman Framework cell name, intersection of Where/Network Nodes and Operations Instance Classes/Workers as Participants.

network node

1. An addressable device or connection point attached to a network.
2. Zachman Framework column name, matches Where.

Network Representation

Zachman Framework cell name, intersection of Where/Network Nodes and System Logic/Architects as Designers.

Network Specification

Zachman Framework cell name, intersection of Where/Network Nodes and Technology Physics/Engineers as Builders.

network taxonomy

SEE taxonomy, network.

Network-Attached Storage (NAS)

A form of storage that attaches to a network but does not provide server functions such as file management.

niche marketing

A marketing segmentation strategy in which the firm focuses on serving one segment of the market. Similar to segmented marketing, but a niche is a small distinguishable segment that can be uniquely served.

Nijssens Information Analysis Method (NIAM)

A data modeling technique, the predecessor to object role modeling. Has also been called “Natural Information Analysis Method”.

no file data modeling scheme

SEE data modeling scheme, no file.

node

In graph theory, a generic representation of something in a graph; could be a type (representing a population), or an individual instance. Usually represented by some icon (e.g., box, circle) in the diagram.

noise

Unwanted sound or data included with or around wanted sound or data.

nomenclature

A systematic naming of things or a system of names or terms for things. In classification, nomenclature involves a systemic naming of categories or items.

nominal number

A number system that has no arithmetic or ordering significance, hence can only be compared as match or no match. Other operators are meaningless - multiply, divide, add, subtract, comparative (<, =,...), or Boolean. This is probably the most commonly occurring type of numerical data in database. Examples include account numbers. Often used as codes for particular characteristics or values in the real world.

non-clustered index

SEE index, non-clustered.

Non-Disclosure Agreement (NDA)

An agreement between parties to not share specific confidential information without proper authorization from other involved parties.

non-functional requirement

SEE requirement, non-functional.

non-identifying relationship

SEE relationship, non-identifying.

non-information

A set of data in context that is not relevant or timely to the recipient. (Brackett 2011)

non-tabular data

SEE data, non-tabular.

normal distribution

A mathematical distribution of points around an axis that represents the mean of the data set values, which resembles a bell (low at both ends and high in the middle).

normal form

A characteristic of a file or table that indicates that it satisfies one or more of the rules of normalization. Not all rules must be satisfied in order. SEE ALSO normalize.

Normal Form, Boyce/Codd (BCNF)

A level of normalization where every attribute or combination of attributes that can uniquely identify an instance is identified as a candidate key. Violations are known as overlapping keys.

Normal Form, Domain/Key (DKNF)

A level of normalization that requires that a database only contains key constraints and domain constraints.

Normal Form, Elementary Key (EKNF)

A level of normalization where there are no candidate keys that re-use the same attribute.

Normal Form, fifth (5NF)

An advanced level of normalization where all attributes of a concatenated key are independent of each other and cannot be derived from the remainder of the key. Violations are commonly known as inter-entity dependencies.

Normal Form, first (1NF)

1. A level of normalization where exist no multi-valued dependencies within a record or row; all attributes are atomic (single valued) for each entity instance. Multi-valued attributes and repeating groups must be removed from the record. In practice, any relational database table with a primary key assumes first normal form.
2. A table structure is in 1NF when it satisfies the six properties of a relation:

1. All rows are unique
2. Order of rows is unimportant
3. All columns have unique names
4. Order of columns is unimportant
5. All values in a column are the same type
6. No column contains multiple values in the same row

Normal Form, fourth (4NF)

An advanced level of normalization where no instance contains two or more independent multi-valued facts. Violations are commonly known as derived data.

Normal Form, Project Join (PJNF)

SEE Normal Form, fifth.

Normal Form, second (2NF)

A level of normalization where every non-key attribute is fully dependent on the key in its entirety. In practice, when entities have compound keys, seek out any attribute that is dependent upon only part of the key and create a separate entity for what is identifiable by anything less than the whole key. Violations are commonly known as partial key dependencies.

Normal Form, sixth (6NF)

1. An advanced level of normalization that adds temporal constraints upon relations, such as a range of time when a relationship was effective. SEE ALSO database, temporal.
2. Sometimes used incorrectly to refer to Domain/Key Normal Form; not the same as definition 1.

Normal Form, third (3NF)

A form of normalization where every entity has no transitive dependencies, that is, every data item must be directly determined by the identifier, and not indirectly determined through some other non-key attribute. For example, if the boss of a department were determined by the department, then it would be incorrect to store both the department ID and the boss name in the employee record. Violations are commonly known as inter-attribute dependencies. Sometimes colloquially referred to as “the key, the whole key, and nothing but the key.”

normalize

1. Verb. Generally, to impose standards or regulations, or bring to a desired state.
2. Verb. In data modeling, to apply rules to a record-based data structure to reduce redundancy, such that each data attribute is stored

The rules of normalization are applied only within a record or table, and cannot be applied until an identifier is first designated for the table. Even though the rules of normalization are numbered, there is no necessary ordering -- they can be applied in any order, and some may be satisfied while others are not. For example, a record may have no transitive dependencies (thus not violating the condition for 3NF) but may have a partial dependency (thus failing 2NF).

normative model

A model that describes how a system should work according to assumptions or pre-defined standards.

North American Industrial Classification System (NAICS)

A taxonomy of business classification, replacing the Standard Industry Code. The North American Industry Classification System is the standard used by Federal statistical agencies in classifying business establishments for the purpose of collecting, analyzing, and publishing statistical data related to the U.S. business economy. NAICS was developed jointly by the U.S. Economic Classification Policy Committee, Statistics Canada, and Mexico's Instituto Nacional de Estadistica y Geografia, to allow for a high level of comparability in business statistics among the North American countries.

Not Only SQL (NoSQL)

A type of database that is distributed to enable large-scale data access.

noun

A type of word that describes a person, a place, a thing, or an idea. One of the syntactic components used to construct sentences according to a grammar.

n-tier architecture

SEE architecture, multi-tier.

null

The absence of any value. A null value tells you the value does not exist. It does not denote why the value is missing. Placing a zero or blank in the row would not reflect the accurate state of the row, because zero and blank are values. In ASCII, null is hex 00, blank is hex 20, and zero is hex 30. In EBCDIC, null is hex 00, blank is hex 40, and zero is hex F0. SQL supports the notion of null values as a way to search for missing data.

null hypothesis

1. Generally, the prediction that an observed result is not due to any inherent systemic cause.
2. In data analysis, the prediction that one variable has no association with and responds independently of another variable.

number

A class word, abbreviated usually to num.