The associative model of data is an alternative data model for database systems. Other data models, such as the relational model and the object data model, are record-based. These models involve encom ...
Plain text files usually contain one record per line, There are different conventions for depicting data. In comma-separated values and delimiter-separated values files, fields can be separated by del ...
Given the textsT = "it is what it is"T = "what is it"T = "it is a banana"we have the following inverted file index (where the integers in the set notation brackets refer to the indexes (or keys) of th ...
A physical data model (or database design) is a representation of a data design which takes into account the facilities and constraints of a given database management system. In the lifecycle of a pro ...
The star schema separates business process data into facts, which hold the measurable, quantitative data about a business, and dimensions which are descriptive attributes related to fact data. Example ...
Attribute metadataValidation metadata include data type, range of permissible values or membership in a set of values, regular expression match, default value, and whether the value is permitted to be ...
Entity–attribute–value model (EAV) is a data model to describe entities where the number of attributes (properties, parameters) that can be used to describe them is potentially vast, but the number ...
The EER modelSee also: ER Modelling and UML ModellingThe EER model includes all of the concepts introduced by the ER model. Additionally it includes the concepts of a subclass and superclass (Is-a), a ...
Though data is also increasingly used in other fields it has been suggested that the highly interpretive nature of them might be at odds with the ethos of data as "given". Peter Checkland introduced t ...
In computer security, general access control includes authorization, authentication, access approval, and audit. A more narrow definition of access control would cover only access approval, whereby th ...
Main article: Physical securityUnderground entrance to the New York City Subway systemPhysical security access control with a hand geometry scannerExample of fob based access control using an ACT read ...
Second Level of Data IndependenceThe physical structure of the data is referred to as "physical data description". Physical data independence deals with hiding the details of the storage structure fro ...
A basic objective of the first normal form defined by Codd in 1970 was to permit data to be queried and manipulated using a "universal data sub-language" grounded in first-order logic. (SQL is an exam ...
Logical data models represent the abstract structure of a domain of information. They are often diagrammatic in nature and are most typically used in business processes that seek to capture things of ...
Ideal requirements for schema integrationOverlap preservationEach of the overlapping elements specified in the input mapping is also in a database schema relation.Extended overlap preservationSource-s ...
