The constants below are defined by this extension, and will only be available when the extension has either been compiled into PHP or dynamically loaded at runtime.
   PDO uses class constants since PHP 5.1. Prior releases use global constants
   in the form PDO_PARAM_BOOL.
  
PDO::PARAM_BOOL
     (integer)
   PDO::PARAM_NULL
     (integer)
   PDO::PARAM_INT
     (integer)
   PDO::PARAM_STR
     (integer)
   PDO::PARAM_LOB
     (integer)
   PDO::PARAM_STMT
     (integer)
   PDO::PARAM_INPUT_OUTPUT
     (integer)
   PDO::FETCH_LAZY
     (integer)
   PDO::FETCH_LAZY creates the object variable names as they are accessed.
     Not valid inside PDOStatement::fetchAll().
    
   PDO::FETCH_ASSOC
     (integer)
   PDO::FETCH_ASSOC returns
     only a single value per column name.
    
   PDO::FETCH_NAMED
     (integer)
   PDO::FETCH_NAMED returns
     an array of values per column name.
    
   PDO::FETCH_NUM
     (integer)
   PDO::FETCH_BOTH
     (integer)
   PDO::FETCH_OBJ
     (integer)
   PDO::FETCH_BOUND
     (integer)
   PDO::FETCH_COLUMN
     (integer)
   PDO::FETCH_CLASS
     (integer)
   Note: The magic __set() method is called if the property doesn't exist in the requested class
PDO::FETCH_INTO
     (integer)
   PDO::FETCH_FUNC
     (integer)
   PDO::FETCH_GROUP
     (integer)
   PDO::FETCH_COLUMN or 
     PDO::FETCH_KEY_PAIR.
    
   PDO::FETCH_UNIQUE
     (integer)
   PDO::FETCH_KEY_PAIR
    (integer)
   PDO::FETCH_CLASSTYPE
     (integer)
   PDO::FETCH_SERIALIZE
     (integer)
   PDO::FETCH_INTO but object is provided as a serialized string.
     Available since PHP 5.1.0. Since PHP 5.3.0 the class constructor is never called if this
     flag is set.
    
   PDO::FETCH_PROPS_LATE
     (integer)
   PDO::ATTR_AUTOCOMMIT
     (integer)
   FALSE, PDO attempts to disable autocommit so that the
     connection begins a transaction.
    
   PDO::ATTR_PREFETCH
     (integer)
   PDO::ATTR_TIMEOUT
     (integer)
   PDO::ATTR_ERRMODE
     (integer)
   PDO::ATTR_SERVER_VERSION
     (integer)
   PDO::ATTR_CLIENT_VERSION
     (integer)
   PDO::ATTR_SERVER_INFO
     (integer)
   PDO::ATTR_CONNECTION_STATUS
     (integer)
   PDO::ATTR_CASE
     (integer)
   PDO::ATTR_CURSOR_NAME
     (integer)
   PDO::ATTR_CURSOR
     (integer)
   PDO::CURSOR_FWDONLY and 
     PDO::CURSOR_SCROLL. Stick with
     PDO::CURSOR_FWDONLY unless you know that you need a
     scrollable cursor.
    
   PDO::ATTR_DRIVER_NAME
     (string)
   
Example #1 using PDO::ATTR_DRIVER_NAME
<?php
if ($db->getAttribute(PDO::ATTR_DRIVER_NAME) == 'mysql') {
  echo "Running on mysql; doing something mysql specific here\n";
}
?>
PDO::ATTR_ORACLE_NULLS
     (integer)
   PDO::ATTR_PERSISTENT
     (integer)
   PDO::ATTR_STATEMENT_CLASS
     (integer)
   PDO::ATTR_FETCH_CATALOG_NAMES
     (integer)
   PDO::ATTR_FETCH_TABLE_NAMES
     (integer)
   PDO::ATTR_STRINGIFY_FETCHES
     (integer)
   PDO::ATTR_MAX_COLUMN_LEN
     (integer)
   PDO::ATTR_DEFAULT_FETCH_MODE
     (integer)
   PDO::ATTR_EMULATE_PREPARES
     (integer)
   PDO::ERRMODE_SILENT
     (integer)
   PDO::ERRMODE_WARNING
     (integer)
   E_WARNING message if an error occurs.
     See Errors and error handling
     for more information about this attribute.
    
   PDO::ERRMODE_EXCEPTION
     (integer)
   PDO::CASE_NATURAL
     (integer)
   PDO::CASE_LOWER
     (integer)
   PDO::CASE_UPPER
     (integer)
   PDO::NULL_NATURAL
     (integer)
   PDO::NULL_EMPTY_STRING
     (integer)
   PDO::NULL_TO_STRING
     (integer)
   PDO::FETCH_ORI_NEXT
     (integer)
   PDO::FETCH_ORI_PRIOR
     (integer)
   PDO::FETCH_ORI_FIRST
     (integer)
   PDO::FETCH_ORI_LAST
     (integer)
   PDO::FETCH_ORI_ABS
     (integer)
   PDO::FETCH_ORI_REL
     (integer)
   PDO::CURSOR_FWDONLY
     (integer)
   PDO::CURSOR_SCROLL
     (integer)
   PDO::ERR_NONE
     (string)
   PDO::PARAM_EVT_ALLOC
    (integer)
   PDO::PARAM_EVT_FREE
    (integer)
   PDO::PARAM_EVT_EXEC_PRE
    (integer)
   PDO::PARAM_EVT_EXEC_POST
    (integer)
   PDO::PARAM_EVT_FETCH_PRE
    (integer)
   PDO::PARAM_EVT_FETCH_POST
    (integer)
   PDO::PARAM_EVT_NORMALIZE
    (integer)