Description:
------------
There seems to be a difference between PHP5 and PHP7 in oci8 when binding NULL values to LONG/LOB type columns.

In PHP5 it was possible to execute the following INSERT statement without any error (sample):

INSERT INTO mytable VALUES (:clob_col, :varchar2_col)

If the value bound to parameter :varchar2_col is NULL, the following error is triggered (no matter what value the parameter :clob_col is bound to):

ORA-24816: Expanded non LONG bind data supplied after actual LONG or LOB column

If you switch the parameter order and both parameter values are bound to NULL, the same error occurs:

INSERT INTO mytable VALUES (:varchar2_col, :clob_col)

So no matter what order, not matter what value is bound to :clob_col, if :varchar2_col is bound to NULL, the error occurs.

If you have only one VARCHAR2 column or two (without a CLOB column) there also is no error.

Test script:
---------------
<?php

$conn = oci_connect('system', 'oracle', '(DESCRIPTION=(ADDRESS=(PROTOCOL=TCP)(HOST=localhost)(PORT=1521))(CONNECT_DATA=(SID=xe)))');

$stmt = oci_parse($conn, 'DROP TABLE mytable');
oci_execute($stmt);

$stmt = oci_parse($conn, 'CREATE TABLE mytable ("clob_col" CLOB DEFAULT NULL, "varchar2_col" VARCHAR2(255) DEFAULT NULL)');
oci_execute($stmt);

$stmt = oci_parse($conn, 'INSERT INTO mytable VALUES (:clob_col, :varchar2_col)');

$clob = null;
$varchar2 = null;
oci_bind_by_name($stmt, ':clob_col', $clob);
oci_bind_by_name($stmt, ':varchar2_col', $varchar2);

var_dump(oci_execute($stmt));

Expected result:
----------------
bool(true)

Actual result:
--------------
PHP Warning:  oci_execute(): ORA-24816: Expanded non LONG bind data supplied after actual LONG or LOB column in /home/deeky/dev/doctrine/dbal/oci8_php7.php on line 14

Warning: oci_execute(): ORA-24816: Expanded non LONG bind data supplied after actual LONG or LOB column in /home/deeky/dev/doctrine/dbal/oci8_php7.php on line 14
bool(false)