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A classification of SQL injection attacking vector as of 2010. In computing, SQL injection is a code injection technique used to attack data-driven applications, in which malicious SQL statements are inserted into an entry field for execution (e.g. to dump the database contents to the attacker).
A function is bijective if it is both injective and surjective. A bijective function is also called a bijection or a one-to-one correspondence (not to be confused with one-to-one function, which refers to injection). A function is bijective if and only if every possible image is mapped to by exactly one argument. [1]
The syntax of the IIf function is as follows: . IIf(expr, truepart, falsepart) . All three parameters are required: e expr is the expression that is to be evaluated.; truepart defines what the IIf function returns if the evaluation of expr returns true.
An SQL injection takes advantage of SQL syntax to inject malicious commands that can read or modify a database or compromise the meaning of the original query. [13] For example, consider a web page that has two text fields which allow users to enter a username and a password.
Major DBMSs, including SQLite, [5] MySQL, [6] Oracle, [7] IBM Db2, [8] Microsoft SQL Server [9] and PostgreSQL [10] support prepared statements. Prepared statements are normally executed through a non-SQL binary protocol for efficiency and protection from SQL injection, but with some DBMSs such as MySQL prepared statements are also available using a SQL syntax for debugging purposes.
SQL includes operators and functions for calculating values on stored values. SQL allows the use of expressions in the select list to project data, as in the following example, which returns a list of books that cost more than 100.00 with an additional sales_tax column containing a sales tax figure calculated at 6% of the price.
For instance, a user-supplied value might be inserted into a database, protected by magic quotes, and later retrieved from the database and used in a subsequent database operation. The latter use is not protected by magic quotes, and a naive programmer used to relying on them may be unaware of the need to protect it explicitly.
An injective function which is a homomorphism between two algebraic structures is an embedding. Unlike surjectivity, which is a relation between the graph of a function and its codomain, injectivity is a property of the graph of the function alone; that is, whether a function f {\displaystyle f} is injective can be decided by only considering ...