Search results
Results from the WOW.Com Content Network
A relational DBM uses related data fields (columns) to correlate information between tables. [5] For example, two tables, transaction_user and transaction_amount, would both contain the column "key", and keys between tables would match, making it easy to find both the user and the amount of a specific transaction if the key is known.
Set operations in SQL is a type of operations which allow the results of multiple queries to be combined into a single result set. [ 1 ] Set operators in SQL include UNION , INTERSECT , and EXCEPT , which mathematically correspond to the concepts of union , intersection and set difference .
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.
Views can represent a subset of the data contained in a table. Consequently, a view can limit the degree of exposure of the underlying tables to the outer world: a given user may have permission to query the view, while denied access to the rest of the base table. [2] Views can join and simplify multiple tables into a single virtual table. [2]
A table in a SQL database schema corresponds to a predicate variable; the contents of a table to a relation; key constraints, other constraints, and SQL queries correspond to predicates. However, SQL databases deviate from the relational model in many details, and Codd fiercely argued against deviations that compromise the original principles. [3]
Get AOL Mail for FREE! Manage your email like never before with travel, photo & document views. Personalize your inbox with themes & tabs. You've Got Mail!
An Oregon man was arrested and charged Thursday for the murder of a car dealership owner who disappeared three years ago, police said Monday. Murphy Henry, 54, was also charged with abuse of a ...
By Jody Godoy (Reuters) -Grubhub settled with the U.S. Federal Trade Commission and Illinois Attorney General Kwame Raoul on Tuesday for allegedly misleading customers about order fees, adding ...