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  2. Unique key - Wikipedia

    en.wikipedia.org/wiki/Unique_key

    A key is not necessarily a unique identifier across the population of all possible instances of tuples that could be stored in a table but it does imply a data integrity rule that duplicates should not be allowed in the database table. Some possible examples of keys are Social Security Numbers, ISBNs, vehicle registration numbers or user login ...

  3. Surrogate key - Wikipedia

    en.wikipedia.org/wiki/Surrogate_key

    A surrogate key (or synthetic key, pseudokey, entity identifier, factless key, or technical key [citation needed]) in a database is a unique identifier for either an entity in the modeled world or an object in the database. The surrogate key is not derived from application data, unlike a natural (or business) key. [1]

  4. Unique identifier - Wikipedia

    en.wikipedia.org/wiki/Unique_identifier

    A unique identifier (UID) is an identifier that is guaranteed to be unique among all identifiers used for those objects and for a specific purpose. [1] The concept was formalized early in the development of computer science and information systems. In general, it was associated with an atomic data type.

  5. Universally unique identifier - Wikipedia

    en.wikipedia.org/wiki/Universally_unique_identifier

    A Universally Unique Identifier (UUID) is a 128-bit label used to uniquely identify objects in computer systems. The term Globally Unique Identifier (GUID) is also used, mostly in Microsoft systems. [1] [2] When generated according to the standard methods, UUIDs are, for practical purposes, unique.

  6. Primary key - Wikipedia

    en.wikipedia.org/wiki/Primary_key

    In the relational model of databases, a primary key is a designated attribute that can reliably identify and distinguish between each individual record in a table.The database creator can choose an existing unique attribute or combination of attributes from the table (a natural key) to act as its primary key, or create a new attribute containing a unique ID that exists solely for this purpose ...

  7. Category:Unique identifiers - Wikipedia

    en.wikipedia.org/wiki/Category:Unique_identifiers

    Universal identifiers represent various schemes used to uniquely reference people, companies, and other things across domains, systems and organizations.

  8. Hi/Lo algorithm - Wikipedia

    en.wikipedia.org/wiki/Hi/Lo_algorithm

    Hi/Lo is an algorithm and a key generation strategy used for generating unique keys for use in a database as a primary key. It uses a sequence-based hi-lo pattern to generate values. Hi/Lo is used in scenarios where an application needs its entities to have an identity prior to persistence. It is a value generation strategy.

  9. Strongly typed identifier - Wikipedia

    en.wikipedia.org/wiki/Strongly_typed_identifier

    The data type should preferably be immutable if possible. It is common for implementations to handle equality testing, serialization and model binding. The strongly typed identifier commonly wraps the data type used as the primary key in the database, such as a string, an integer or universally unique identifier (UUID).