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2. Database model - Wikipedia

   en.wikipedia.org/wiki/Database_model

   Thus, the "relation" in "relational database" refers to the various tables in the database; a relation is a set of tuples. The columns enumerate the various attributes of the entity (the employee's name, address or phone number, for example), and a row is an actual instance of the entity (a specific employee) that is represented by the relation.

3. Candidate key - Wikipedia

   en.wikipedia.org/wiki/Candidate_key

   The columns in a candidate key are called prime attributes, [3] and a column that does not occur in any candidate key is called a non-prime attribute. Every relation without NULL values will have at least one candidate key: Since there cannot be duplicate rows, the set of all columns is a superkey, and if that is not minimal, some subset of ...

4. Unique key - Wikipedia

   en.wikipedia.org/wiki/Unique_key

   Simple A key made from only one attribute. Concatenated A key made from more than one attribute joined together as a single key, such as part or whole name with a system generated number appended as often used for E-mail addresses. Compound: A key made from at least two attributes or simple keys, only simple keys exist in a compound key. Composite

5. Attribute (computing) - Wikipedia

   en.wikipedia.org/wiki/Attribute_(computing)

   An attribute in a relational database can be represented as a column or field. In computing, an attribute is a specification that defines a property of an object, element, or file. It may also refer to or set the specific value for a given instance of such. For clarity, attributes should more correctly be considered metadata. An attribute is ...

6. Amazon SimpleDB - Wikipedia

   en.wikipedia.org/wiki/Amazon_SimpleDB

   Amazon SimpleDB is a distributed database written in Erlang [1] by Amazon.com. It is used as a web service in concert with Amazon Elastic Compute Cloud (EC2) and Amazon S3 and is part of Amazon Web Services .

7. Database design - Wikipedia

   en.wikipedia.org/wiki/Database_design

   Database design is the organization of data according to a database model. The designer determines what data must be stored and how the data elements interrelate. With this information, they can begin to fit the data to the database model. [1] A database management system manages the data accordingly.