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The following table lists the standard-conforming values - based on SQL:2011. [1] The table's last column shows the part of the standard that defines the row. If it is empty, the definition originates from part 2 Foundation .
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 ...
In order to explain column-level encryption it is important to outline basic database structure. 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 ...
A check constraint is a type of integrity constraint in SQL which specifies a requirement that must be met by each row in a database table. The constraint must be a predicate . It can refer to a single column, or multiple columns of the table.
Transparent Data Encryption (often abbreviated to TDE) is a technology employed by Microsoft, IBM and Oracle to encrypt database files. TDE offers encryption at file level. TDE enables the encryption of data at rest, encrypting databases both on the hard drive and consequently on backup media.
A table (called the referencing table) can refer to a column (or a group of columns) in another table (the referenced table) by using a foreign key. The referenced column(s) in the referenced table must be under a unique constraint, such as a primary key. Also, self-references are possible (not fully implemented in MS SQL Server though [5]).
A main encryption/decryption key is derived from user's password by PBKDF2 function. [2] Particular data binary large objects can be encrypted in a way that salt is added and/or an external user-prompted password (aka "Strong Key Protection") is required. The use of a salt is a per-implementation option – i.e. under the control of the ...
E. F. Codd mentioned nulls as a method of representing missing data in the relational model in a 1975 paper in the FDT Bulletin of ACM-SIGMOD.Codd's paper that is most commonly cited with the semantics of Null (as adopted in SQL) is his 1979 paper in the ACM Transactions on Database Systems, in which he also introduced his Relational Model/Tasmania, although much of the other proposals from ...