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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).
[5] [6] Code injection could, for example: Introduce a useful new column that did not appear in the original design of a search results page. Offer a new way to filter, order, or group data by using a field not exposed in the default functions of the original design. Add functionality like connecting to online resources in an offline program.
Magic quotes also use the generic functionality provided by PHP's addslashes() function, which is not Unicode-aware and is still subject to SQL injection vulnerabilities in some multi-byte character encodings. Database-specific functions such as mysql_real_escape_string() or, where possible, prepared queries with bound parameters, are preferred ...
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.
A function is injective (one-to-one) if each possible element of the codomain is mapped to by at most one argument. Equivalently, a function is injective if it maps distinct arguments to distinct images. An injective function is an injection. [1] The formal definition is the following.
A prologue comment is a comment (or group of related comments) located near the top of an associated programming topic, such as before a symbol declaration or at the top of a file. An inline comment is a comment that is located on the same line as and to the right of program code to which is refers. [ 8 ]
For instance, documentation for an API function could note that its parameters cannot be null, that the function itself is not thread safe. [56] Because API documentation tends to be comprehensive, it is a challenge for writers to keep the documentation updated and for users to read it carefully, potentially yielding bugs.