K
Kagi chart
SEE chart, Kagi.
kaizen
The Japanese word for “continuous improvement”.
kernel entity
SEE entity, kernel.
key
- A data item or combination of data items designated to uniquely identify a particular entity instance or table row. SEE ALSO identifier.
- Adjective. Critically important.
key constraint
SEE constraint, key.
Key Performance Indicator (KPI)
A business calculation (metric) with associated target values or ranges that allows macro level insights into the business process to manage profitability and monitor strategic impact.
key, alternate
Alternate form: secondary key
A unique identifier for an entity instance other than the primary key. Usually an alternate key is a unique natural key.
key, business
Alternate form: domain key, natural key
- An identifier familiar to and used by data consumers, using existing attributes, which has a logical relationship to the attributes within the row.
- A primary key that uses attributes that have meaning to the business. Opposite of a surrogate key.
key, candidate
A key that can uniquely identify occurrences of an entity. Each occurrence must have a different key value, and every attribute in the key is needed to uniquely identify each occurrence. Such identifiers are “candidates” to become a primary key, and candidate keys not selected as the primary key are considered alternate keys.
key, composite
A key that is made up of more than one attribute.
Key, Foreign (FK)
- An attribute (or attributes) in a relational table which is from the same domain as the identifier of the same or another table; can be thought of as a logical pointer from the “referencing” entity table (with the foreign key) to the “referenced” entity table (with the identifier). It is used to represent a many-to-one relationship between the referencing and referenced tables. It is not necessary for a foreign key to have a value; that is determined by the independently defined dependency characteristic.
- The preferred primary key of a parent data subject that is placed in a subordinate data subject to identify the relevant parent data occurrence in that parent data subject.
key, hash
A number based on the hash value of a string.
key, intelligent
A key value that has some meaning assigned to the values other than just as a link to rows in other tables. For example, the key of a CALENDAR_DIM could be of the format “CCYYMMDD” in order to enable truncation of the key for partitioning into time-based segments.
key, partial
A portion of a key, in which each value of the partial key may identify more than one unique instance (record) in the file or data set.
Key, Primary (PK)
A set of one or more data attributes whose values are used to uniquely identify an entity instance or relational database table row. The primary key will have a unique value for each record or row in the table and is the means of navigation across entities and tables. Primary key attributes and values of parent entities and tables appear as foreign key attributes and values in child entities and tables.
key, secondary
A key whose value identifies a set of occurrences in a data structure that share common characteristics. Access by secondary keys may return multiple occurrences, where access by a primary key is assured to find no more than one occurrence.
key, superkey
A set of attributes in a dataset such that there are no repeated value sets. Each combination of the values in the attributes in a superkey are unique.
key, surrogate
Alternate form: dummy key
A single-part, artificially established, physical identifier for a data set, usually not visible to business users, and used for database management and performance. Surrogate key assignment is a special case of derived data - one where the primary key is derived. A common way of deriving surrogate key values is to assign integer values sequentially. Sometimes referred to as a dummy key, sequential key, or auto-number field.
keyword
A term found in a document, indexed to enable document search and location.
Kilobyte (Kb)
A thousand bytes of storage.
k-nearest neighbor algorithm
A modeling technique that assigns values to points based on the values of the k nearby points, such as average value, or most common value. SEE ALSO predictive modeling.
knowledge
- Generally, expertise; familiarity gained through experience or association; cognizance, the fact or condition of knowing something; the acquaintance with or the understanding of something; the fact or condition of being aware of something, of apprehending truth or fact.
- Understanding; awareness, cognizance, and the recognition of a situation and familiarity with its complexity. Understanding of the significance of information; information in perspective, integrated into a viewpoint based on the recognition of patterns (such as trends and causes) based on other information and experience. (DAMA-DMBOK Guide, 1st edition, pg. 3.)
knowledge base
A database of rules, usually expressed in an if/then format, used in an expert system.
Knowledge Discovery in Databases (KDD)
SEE data mining.
Knowledge Interchange Format (KIF)
A standard format for exchanging rules between artificial intelligence (AI) systems.
Knowledge Management (KM)
- The management of an environment where people generate tacit knowledge, render it into explicit knowledge, and feed it back to the organization. The cycle forms a base for more tacit knowledge, which keeps the cycle going in an intelligent learning organization. (Brackett 2011)
- The discipline that fosters organizational learning and the management of intellectual capital as an enterprise resource. (DAMA-DMBOK Guide, 1st edition, pg. 3.)
knowledge worker
Anyone who works for a living by understanding information. A type of information consumer. Knowledge workers seek to gain expertise though the understanding of information, and then apply that expertise by making informed and aware decisions and actions.
knowledge, explicit
Knowledge that is easily codified, shared, documented, and explained.
knowledge, tacit
Knowledge that is based on experience and not easy to share, document, or explain.