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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 .
Column level encryption is a type of database encryption method that allows user to select specific information or attributes to be encrypted instead of encrypting the entire database file. To understand why column level encryption is different from other encryption methods like file level encryption , disk encryption , and database encryption ...
A typical relational database is divided into tables that are divided into columns that each have rows of data. [10] Whilst TDE usually encrypts an entire database, column-level encryption allows for individual columns within a database to be encrypted. [11]
Title Authors ----- ----- SQL Examples and Guide 4 The Joy of SQL 1 An Introduction to SQL 2 Pitfalls of SQL 1 Under the precondition that isbn is the only common column name of the two tables and that a column named title only exists in the Book table, one could re-write the query above in the following form:
This trigger is called on an update to a phone book database. When the trigger is called it adds an entry into a separate table named phone_book_audit. Also take note of triggers being able to take advantage of schema objects like sequences, [ 8 ] in this example audit_id_sequence.nexVal is used to generate unique primary keys in the phone_book ...
A data control language (DCL) is a syntax similar to a computer programming language used to control access to data stored in a database (authorization). In particular, it is a component of Structured Query Language (SQL). Data Control Language is one of the logical group in SQL Commands.
To allow several users to edit a database table at the same time and also prevent inconsistencies created by unrestricted access, a single record can be locked when retrieved for editing or updating. Anyone attempting to retrieve the same record for editing is denied write access because of the lock (although, depending on the implementation ...
The Database Master Key is used in conjunction with a certificate to encrypt the Database Encryption Key. The Database Encryption Key is used to encrypt the underlying database files with either the AES or 3DES cipher. The master database that contains various system level information, user accounts and management services is not encrypted ...