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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.
Primary key. In the relational model of databases, a primary key is a specific choice of a minimal set of attributes ( columns) that uniquely specify a tuple ( row) in a relation ( table ). [a] [1] Informally, a primary key is "which attributes identify a record," and in simple cases constitute a single attribute: a unique ID.
Identity column. An identity column is a column (also known as a field) in a database table that is made up of values generated by the database. This is much like an AutoNumber field in Microsoft Access or a sequence in Oracle. Because the concept is so important in database science, many RDBMS systems implement some type of generated key ...
Natural key. A natural key (also known as business key [1] or domain key [2]) is a type of unique key in a database formed of attributes that exist and are used in the external world outside the database (i.e. in the business domain or domain of discourse ). [3] In the relational model of data, a natural key is a superkey and is therefore a ...
Serge Massar was born in Zambia in 1970. [2] He obtained a degree in physics, then a PhD from the Université libre de Bruxelles (ULB) in 1991 and 1995, respectively. [2] He completed his post-doctoral research at Tel Aviv University from 1995 to 1997, and subsequently at Utrecht University from 1997 to 1998. [2] [3]
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The terms "tabular key" and "matrix key" are best limited to a tabular presentation format of multi-access keys. The term "synoptic key" has an older definition, defining it as a key reflecting taxonomic classification and opposed to diagnostic keys arranged solely for the convenience of identification. History
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 .