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The current revision of the PHP manual mentions that the rationale behind magic quotes was to "help [prevent] code written by beginners from being dangerous." [2] It was however originally introduced in PHP 2 as a php.h compile-time setting for msql, only escaping single quotes, "making it easier to pass form data directly to msql queries". [3]
A single word may not be as meaningful, or specific, as multiple words. Consequently, some naming conventions specify rules for the treatment of "compound" identifiers containing more than one word. Consequently, some naming conventions specify rules for the treatment of "compound" identifiers containing more than one word.
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 ...
In SQL, wildcard characters can be used in LIKE expressions; the percent sign % matches zero or more characters, and underscore _ a single character. Transact-SQL also supports square brackets ([and ]) to list sets and ranges of characters to match, a leading caret ^ negates the set and matches only a character not within the list.
A value greater than \U0000FFFF may be represented by a single wchar_t if the UTF-32 encoding is used, or two if UTF-16 is used. Importantly, the universal character name \u00C0 always denotes the character "À", regardless of what kind of string literal it is used in, or the encoding in use. The octal and hex escape sequences always denote ...
m4: A backtick together with an apostrophe quotes strings (to suppress or defer macro expansion). MySQL/MariaDB: A backtick in queries is a delimiter for column, table, and database identifiers. OCaml: The backtick indicates polymorphic variants. Pico: The backtick indicates comments in the programming language.
It also supports >REPLACE INTO syntax, [6] which first attempts an insert, and if that fails, deletes the row, if exists, and then inserts the new one. There is also an IGNORE clause for the INSERT statement, [ 7 ] which tells the server to ignore "duplicate key" errors and go on (existing rows will not be inserted or updated, but all new rows ...
SQL-92 was the third revision of the SQL database query language.Unlike SQL-89, it was a major revision of the standard. Aside from a few minor incompatibilities, the SQL-89 standard is forward-compatible with SQL-92.