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An index normally includes a "key" or direct link to the original row of data from which it was copied, to allow the complete row to be retrieved efficiently. Some databases extend the power of indexing by letting developers create indexes on column values that have been transformed by functions or expressions.
Attribute-based access control (ABAC), also known as policy-based access control for IAM, defines an access control paradigm whereby a subject's authorization to perform a set of operations is determined by evaluating attributes associated with the subject, object, requested operations, and, in some cases, environment attributes.
The rules of the two-phase locking protocol must be observed. [1] Specialized concurrency control techniques exist for accessing indexes. These techniques depend on the index type, and take advantage of its structure. They are typically much more effective than applying to indexes common concurrency control methods applied to user data.
The terms schema matching and mapping are often used interchangeably for a database process. For this article, we differentiate the two as follows: schema matching is the process of identifying that two objects are semantically related (scope of this article) while mapping refers to the transformations between the objects.
For referential integrity to hold in a relational database, any column in a base table that is declared a foreign key can only contain either null values or values from a parent table's primary key or a candidate key. [2] In other words, when a foreign key value is used it must reference a valid, existing primary key in the parent table.
Logical access controls enforce access control measures for systems, programs, processes, and information. The controls can be embedded within operating systems, applications, add-on security packages, or database and telecommunication management systems.
In computer security, organization-based access control (OrBAC) is an access control model first presented in 2003. The current approaches of the access control rest on the three entities ( subject , action , object ) to control the access the policy specifies that some subject has the permission to realize some action on some object.
In computer systems security, Relationship-based access control (ReBAC) defines an authorization paradigm where a subject's permission to access a resource is defined by the presence of relationships between those subjects and resources. In general, authorization in ReBAC is performed by traversing the directed graph of relationships.