Surrogate Key:
Surrogate keys are keys that have no "business" meaning and are solely used to identify a record in the table. Such keys are either database generated (example: Identity in SQL Server, Sequence in Oracle, Sequence/Identity in DB2 UDB etc.) or system generated values (like generated via a table in the schema).
Natural Key:
Keys are natural if the attribute it represents is used for identification independently of the database schema. What this basically means is that the keys are natural if people use them example: Invoice-Numbers, Tax-Ids, SSN etc.
super key foreign key candidate key surrogate key unique key alternate key composite key compound key
establishing a relation between two tables called fornkey.......the colum name should be unique is called "primary key"...a table contain only one primary key...a table contain more then one fornkey....
The foreign key is a reference to a key (identifier) of a row in another or even the same table. When the foreign key is not null, it implies that there's an entry in the referenced table with that identifier. The syntax depends on wich database are you using, check the page in the related links below.
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A surrogate key is an artificial PK introduced by the designer with the purpose of simplifying the assignment of primary keys to tables. Use a Surrogate when you do not want or need the key to have business meaning.
There is no difference.
An artificial key is a surrogate key, often an auto-incremented numeric value, used to uniquely identify records in a database when a natural key is not available or appropriate. Artificial keys are generated and managed by the database system, providing a simple and efficient way to uniquely identify records.
There are five types of keys in database management system . The name of the five keys are as follows .:1) surrogate key -which is the system generated primary key .2) Primary key - same function as surrogate key but user defined.3) candidate key -combination of two more keys.4) alternate keys - alternative for candidate keys.5) foreign key - primary key of another table.There are five types of keys in database management system.These five keys are surrogate, primary, candidate, alternate, foreign keys .
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intermolecular attractions
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intermolecular attractions
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There are many keys in database each having particular use. Types of keys in database are : Primary key, candidate key, alternate key, foreign key, surrogate key.
super key foreign key candidate key surrogate key unique key alternate key composite key compound key