U

unary

1. Adjective. Consisting of only one component or value.
2. In Object Role Models, describes a predicate consisting of a single object.

undo

Verb. To rollback or undo a transaction prior to any commit of that transaction.

Unicode

A character set rich enough to represent languages such as Chinese.

Unified Modeling Language (UML)

The dominant modeling language for object-oriented analysis and design, developed by Jacobsen, Booch, and Rumbaugh, by consolidating several earlier object-oriented modeling standards. Fundamentally, UML is a process-centric modeling scheme.

Uniform Product Code (UPC)

SEE universal product code.

Uniform Resource Identifier (URI)

The unambiguous location of a resource in RDF. SEE ALSO Semantic Web, The.

Uniform Resource Locator (URL)

A resolvable location for a document on the Internet. The path information in an HTML coded source file used to locate another document or image. The format for the URL is scheme://host- domain[:port]/path/filename.

UNION

A SQL set operator that concatenates two tabular SELECT answer sets with consistent column structures into one distinct answer set table.

UNION ALL

A SQL set operator that concatenates two tabular SELECT answer sets with consistent column structures into one answer set table, including all duplicates.

unique identifier

A redundant synonym of identifier. Identifiers are unique by definition. SEE identifier.

unique index

SEE index, unique.

uniqueness

The quality of having no entity existing more than once within a data set.

unit of recovery

An operation within a unit of work that might need to be undone.

unit of work

A set of operations performing a logical outcome in which either all changes are successfully performed, or none are performed.

unit test

SEE test, unit.

United States Postal Service (USPS)

US Government agency responsible for assigning two-character codes for US states and territories. Similar codes were adopted by Canada for its provinces and territories.

Universal Character Set (UCS)

A standard set of characters that may be encoded by different mechanisms.

Universal Description, Discovery, and Integration (UDDI)

A standard format for an XML registry, an online “yellow pages” directory that gives organizations a uniform way to describe their application services, discover other organizations' services and understand the methods required to conduct e-business with a specific company.

Universal Postal Union (UPU)

An agency of the United Nations, responsible for standards in address representation and naming within and for each country.

Universal Product Code (UPC)

A system of identifying things by using a sequence of vertical lines of variable thickness. UPCs are scannable representations of 12-digit numeric codes which represent products and their producers

Universal Standard Products and Services Classification (UNSPSC)

A standard coding system used for classifying products and services offered globally.

Universally Unique Identifier (UUID)

SEE globally unique identifier.

unstructured

Adjective. Not structured, having few formal requirements, or not having a patterned organization. (Brackett 2011)

unstructured data

SEE data, unstructured.

UPDATE

1. Generally, any change to a database, which may also include inserting and deleting data.
2. In SQL, the change of attribute values for one or more existing rows defined by predicate logic. A SQL statement (command) that specifies replacement of data in a relational database.

uplift modeling

A modeling technique that shows the change in probability of an outcome caused by events or actions. SEE ALSO predictive modeling.

upper control limit

SEE control limit, upper.

usage meta-data

SEE meta-data, usage.

use case

1. Generally, a description of behavior given specific input.
2. In Systems Development LifeCycle, the context for process or workflow scenarios.
3. In object-oriented analysis, a work flow scenario defined in order to identify objects, their data and their methods (process steps).

use case diagram

SEE chart, use case diagram.

user

A person or role recognized and authorized to access a particular application. The user’s identity is what confers security authorization. The term has many inappropriate connotations and should be avoided in favor of role-based terms such as business professional, knowledge worker, data producer, or data consumer.

User Acceptance Test (UAT)

SEE test, user acceptance.

user hostile

Adjective. A colloquial way of describing a user interface that is non-intuitive and/or difficult to use.

utility analysis

A method of estimating monetary value of benefit realized by an improvement in worker productivity.