PDOCASEUPPER

PDOCASEUPPER is a term used in discussions of PHP's PDO (PHP Data Objects) to describe the behavior of converting the case of column names in fetch results to upper case. It corresponds to the PDO attribute configuration PDO::ATTR_CASE with the value PDO::CASE_UPPER. When set, fetch results returned as associative arrays will have their column keys in uppercase, regardless of how the columns are named in the database or how the query is written.

Usage and configuration: You can apply this when creating a PDO instance or to a prepared statement. For example, you can configure the PDO instance as follows: $pdo = new PDO($dsn, $user, $pass, array(PDO::ATTR_CASE => PDO::CASE_UPPER)); This setting affects how fetch results are returned in associative arrays. It can also be applied to a statement via setAttribute or similar mechanisms, depending on the driver and PHP version.

Effect and limitations: The CASE_UPPER setting only changes the keys used for column names in fetch results; it does not modify data stored in the database or alter the SQL query itself. The exact behavior can vary by database driver; some drivers may apply the transformation differently, or not at all if they do not support the attribute. It is most useful for normalizing result processing across databases or codebases that expect consistent uppercase column keys.

See also: PDO, PDO::ATTR_CASE, PDO::CASE_UPPER, PDO::CASE_LOWER, PDO::CASE_NATURAL.