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::PARAM_BOOL
     (int)
   PDO::PARAM_NULL
     (int)
   PDO::PARAM_INT
     (int)
   PDO::PARAM_STR
     (int)
   PDO::PARAM_STR_NATL
     (int)
   PDO::PARAM_STR_CHAR
     (int)
   PDO::PARAM_LOB
     (int)
   PDO::PARAM_STMT
     (int)
   PDO::PARAM_INPUT_OUTPUT
     (int)
   PDO::FETCH_DEFAULT
     (int)
   PDO::FETCH_LAZY
     (int)
   PDO::FETCH_LAZY creates the object variable names as they are accessed.
     Not valid inside PDOStatement::fetchAll().
    
   PDO::FETCH_ASSOC
     (int)
   PDO::FETCH_ASSOC returns
     only a single value per column name.
    
   PDO::FETCH_NAMED
     (int)
   PDO::FETCH_NAMED returns
     an array of values per column name.
    
   PDO::FETCH_NUM
     (int)
   PDO::FETCH_BOTH
     (int)
   PDO::FETCH_OBJ
     (int)
   PDO::FETCH_BOUND
     (int)
   PDO::FETCH_COLUMN
     (int)
   PDO::FETCH_CLASS
     (int)
   Note: The magic __set() method is called if the property doesn't exist in the requested class
PDO::FETCH_INTO
     (int)
   PDO::FETCH_FUNC
     (int)
   PDO::FETCH_GROUP
     (int)
   PDO::FETCH_COLUMN or 
     PDO::FETCH_KEY_PAIR.
    
   PDO::FETCH_UNIQUE
     (int)
   PDO::FETCH_KEY_PAIR
    (int)
   PDO::FETCH_CLASSTYPE
     (int)
   PDO::FETCH_SERIALIZE
     (int)
   PDO::FETCH_INTO but object is provided as a serialized string.
     The class constructor is never called if this flag is set.
     Deprecated as of PHP 8.1.0.
    
   PDO::FETCH_PROPS_LATE
     (int)
   PDO::ATTR_AUTOCOMMIT
     (int)
   false, PDO attempts to disable autocommit so that the
     connection begins a transaction.
    
   PDO::ATTR_PREFETCH
     (int)
   PDO::ATTR_TIMEOUT
     (int)
   PDO::ATTR_ERRMODE
     (int)
   PDO::ATTR_SERVER_VERSION
     (int)
   PDO::ATTR_CLIENT_VERSION
     (int)
   PDO::ATTR_SERVER_INFO
     (int)
   PDO::ATTR_CONNECTION_STATUS
     (int)
   PDO::ATTR_CASE
     (int)
   PDO::CASE_*
     constants.
    
   PDO::ATTR_CURSOR_NAME
     (int)
   PDO::ATTR_CURSOR
     (int)
   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
     (int)
   PDO::ATTR_PERSISTENT
     (mixed)
   PDO::ATTR_STATEMENT_CLASS
     (int)
   PDO::ATTR_FETCH_CATALOG_NAMES
     (int)
   PDO::ATTR_FETCH_TABLE_NAMES
     (int)
   PDO::ATTR_STRINGIFY_FETCHES
     (int)
   PDO::ATTR_MAX_COLUMN_LEN
     (int)
   PDO::ATTR_DEFAULT_FETCH_MODE
     (int)
   PDO::ATTR_EMULATE_PREPARES
     (int)
   PDO::ATTR_DEFAULT_STR_PARAM
     (int)
   PDO::PARAM_STR_NATL 
     and PDO::PARAM_STR_CHAR.
    
    
     Available since PHP 7.2.0.
    
   PDO::ERRMODE_SILENT
     (int)
   PDO::ERRMODE_WARNING
     (int)
   E_WARNING message if an error occurs.
     See Errors and error handling
     for more information about this attribute.
    
   PDO::ERRMODE_EXCEPTION
     (int)
   PDO::CASE_NATURAL
     (int)
   PDO::CASE_LOWER
     (int)
   PDO::CASE_UPPER
     (int)
   PDO::NULL_NATURAL
     (int)
   PDO::NULL_EMPTY_STRING
     (int)
   PDO::NULL_TO_STRING
     (int)
   PDO::FETCH_ORI_NEXT
     (int)
   PDO::FETCH_ORI_PRIOR
     (int)
   PDO::FETCH_ORI_FIRST
     (int)
   PDO::FETCH_ORI_LAST
     (int)
   PDO::FETCH_ORI_ABS
     (int)
   PDO::FETCH_ORI_REL
     (int)
   PDO::CURSOR_FWDONLY
     (int)
   PDO::CURSOR_SCROLL
     (int)
   PDO::FETCH_ORI_* constants to control the rows fetched from the result set.
    
   PDO::ERR_NONE
     (string)
   PDO::PARAM_EVT_ALLOC
    (int)
   PDO::PARAM_EVT_FREE
    (int)
   PDO::PARAM_EVT_EXEC_PRE
    (int)
   PDO::PARAM_EVT_EXEC_POST
    (int)
   PDO::PARAM_EVT_FETCH_PRE
    (int)
   PDO::PARAM_EVT_FETCH_POST
    (int)
   PDO::PARAM_EVT_NORMALIZE
    (int)
   PDO::SQLITE_DETERMINISTIC
    (int)