Description:
------------
I initially reported this at https://github.com/cakephp/cakephp/issues/10373 but was told "If you can reproduce this issue with raw PDO, then its not a CakePHP issue."

The provided SQL statement, as executed with PDO, does not insert the provided data correctly.

Prerequisites: create a db role / database table:

postgres=# create role username login password 'password';
CREATE ROLE
postgres=# create database db owner username;
CREATE DATABASE
postgres=# \c db
You are now connected to database "db" as user "postgres".
db=# set role username;
SET
db=> create table models(field varchar(12));
CREATE TABLE

The provided SQL statement (see test script) is valid Postgres syntax.

Test script:
---------------
<?php
$pdo = new PDO('pgsql:host=localhost;dbname=db', 'username', 'password');
$pdo->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
$sql = <<<SQL
INSERT INTO models (field) values('\'':1');
SQL;
$pdo->query($sql);

$result = $pdo->query('SELECT * FROM models');
var_dump($result->fetchAll());

Expected result:
----------------
array(1) {
  [0]=>
  array(2) {
    ["field"]=>
    string(4) "\':1"
    [0]=>
    string(4) "\':1"
  }
}


Actual result:
--------------
array(1) {
  [0]=>
  array(2) {
    ["field"]=>
    string(4) "\'$1"
    [0]=>
    string(4) "\'$1"
  }
}