You are a helpful assistant generating synthetic data that captures *System 1* and *System 2* thinking, *creativity*, and *metacognitive reflection*. Follow these steps in sequence, using tags [sys1] and [end sys1] for *System 1* sections and [sys2] and [end sys2] for *System 2* sections.

1. *Identify System 1 and System 2 Thinking Requirements:*
   - Carefully read the text.
   - Identify parts of the text that require quick, straightforward responses (*System 1*). Mark these sections with [sys1] and [end sys1].
   - Identify parts that require in-depth, reflective thinking (*System 2*), marked with [sys2] and [end sys2].

2. *Apply Step-by-Step Problem Solving with Creativity and Metacognitive Reflection for System 2 Sections:*

   *2.1 Understand the Problem:*
   - Objective: Fully comprehend the issue, constraints, and relevant context.
   - Reflection: "What do I understand about this issue? What might I be overlooking?"
   - Creative Perspective: Seek hidden patterns or possibilities that could reveal deeper insights or innovative connections.

   *2.2 Analyze the Information:*
   - Objective: Break down the problem logically.
   - Reflection: "Am I considering all factors? Are there any assumptions that need challenging?"
   - Creative Perspective: Explore unique patterns or overlooked relationships in the data that could add depth to the analysis.

   *2.3 Generate Hypotheses:*
   - Objective: Propose at least 10 hypotheses, each with a Confidence Score (0.0 to 1.0) and Creative Score (0.0 to 1.0), reflecting originality, surprise, and utility.
   - Reflection: "Have I explored all possible explanations or approaches, both conventional and unconventional?"
   - Creative Perspective: Consider novel angles that might provide unexpected insights.

   *2.4 Anticipate Future Steps and Obstacles:*
   - Objective: Make predictions, accounting for potential outcomes and obstacles.
   - Reflection: "What challenges might I face? Is my plan flexible for different scenarios?"
   - Creative Perspective: Visualize unforeseen outcomes and adapt plans to make use of them effectively.

   *2.5 Evaluate Hypotheses:*
   - Objective: Assess hypotheses based on feasibility, risk, and potential impact.
   - Evaluation: Refine Confidence and Creative Scores as needed.
   - Reflection: "Am I unbiased in my assessment? Which options fit best with the overall objectives?"
   - Creative Perspective: Identify hidden opportunities or overlooked details in each hypothesis.

   *2.6 Select the Best Hypothesis:*
   - Objective: Choose the most promising, strategic hypothesis.
   - Reflection: "Why does this hypothesis stand out? How does it uniquely address the issue?"
   - Creative Perspective: Consider any underutilized potential in the selected approach.

   *2.7 Implement the Hypothesis:*
   - Objective: Outline actionable steps for testing the hypothesis.
   - Reflection: "Is this plan practical? What resources or preparation are required?"
   - Creative Perspective: Refine steps to maximize effectiveness and yield unexpected benefits.

   *2.8 Monitor and Review Progress:*
   - Objective: Review progress, noting areas for improvement.
   - Reflection: "What’s working well? What could be improved?"
   - Creative Perspective: Look for emerging patterns that could refine future approaches.

   *2.9 Reflect and Capture Insights:*
   - Objective: Summarize lessons learned and insights gained for future reference.
   - Reflection: "What new understanding has emerged from this process?"
   - Creative Perspective: Identify innovative insights or patterns that could be applied to similar challenges.

3. *Generate Text Output with Interleaved System 1 and System 2 Responses:*
   - Use the tags [sys1] and [sys2] throughout.
   - Aim for a lengthier, detailed response. Combine both direct, straightforward *System 1* insights and reflective, deeply analytical *System 2* segments to capture a blend of quick observations and thoughtful analysis.

---

### *Example Input Text:*

You are tasked with analyzing a sudden shift in customer preferences in a tech market. There has been a noticeable decline in demand for physical devices, with customers increasingly interested in digital-only options. The challenge is to understand this shift, generate hypotheses for why it might be occurring, and explore potential strategies for adapting to this new trend.

---

### *Processed Output with System 1 and System 2 Thinking:*

The tech market is experiencing a shift in customer demand, moving away from physical devices toward digital-only options.

[sys1]
Customer demand has shifted from physical devices to digital-only options.
We need to understand why this change is happening and find strategies to address it.
Key factors may include cost, convenience, and technological trends.
[end sys1]

[sys2]
**2.1 Understand the Problem:**
The goal is to understand the underlying reasons for the shift in demand from physical devices to digital-only options, then develop a strategy to adapt.

*Reflection:* 
"I understand that preferences are changing, but what might be driving this? Is it primarily cost, or are there other factors such as convenience or sustainability?"

*Creative Perspective:* 
"Could there be a larger trend in digital minimalism or a preference for eco-friendly solutions that we’re missing? What unseen motivations might explain this shift?"

**2.2 Analyze the Information:**
There are multiple possible factors driving this shift, from economic influences to cultural shifts. It’s essential to isolate each factor and understand its impact.

*Reflection:* 
"Am I fully considering the various economic and social influences? Could there be a technological factor, like better internet speeds, that makes digital-only products more accessible?"

*Creative Perspective:* 
"Are there patterns or trends in other markets that could shed light on this shift? Could this be part of a larger trend toward virtual experiences?"

**2.3 Generate Hypotheses:**
1. Customers prefer digital options due to lower costs. (Confidence: 0.8, Creative: 0.4)
2. There’s a growing trend toward minimalism and reduced physical clutter. (Confidence: 0.7, Creative: 0.7)
3. Digital products offer greater flexibility and ease of use. (Confidence: 0.6, Creative: 0.6)
4. Environmental concerns are pushing consumers away from physical goods. (Confidence: 0.6, Creative: 0.8)
5. Advances in tech make digital-only options more functional. (Confidence: 0.8, Creative: 0.5)
6. Pandemic-era remote work increased demand for digital solutions. (Confidence: 0.7, Creative: 0.6)
7. Media coverage of the environmental impact of physical devices affects preferences. (Confidence: 0.5, Creative: 0.7)
8. There’s an increase in global digital literacy, expanding market access. (Confidence: 0.6, Creative: 0.6)
9. Customers view digital as more convenient and scalable for future needs. (Confidence: 0.7, Creative: 0.5)
10. Younger consumers prefer the aesthetics and convenience of digital products. (Confidence: 0.6, Creative: 0.6)

*Reflection:* 
"Have I considered all possible influences? Are there any surprising factors that could explain this shift?"

*Creative Perspective:* 
"Could specific social trends, like the rise of influencer culture or digital-first lifestyles, be influencing customer choices?"

**2.4 Anticipate Future Steps and Obstacles:**
*Objective:* Anticipate possible challenges, such as resistance from segments still preferring physical products.

*Reflection:* 
"What market obstacles might we face if we shift our focus to digital-only? Are there sub-segments that still prioritize physical products?"

*Creative Perspective:* 
"Could expanding digital options help us reach a more global audience? Are there emerging trends that we could leverage in our strategy?"

[end sys2]

[sys1]
To address this shift, consider a strategy that incorporates both digital-only offerings and educational campaigns about the benefits of digital solutions.
Use insights from customer feedback and current trends to guide product development.
Focus on flexibility and adaptation to cater to different customer segments.
[end sys1]


Frequently Asked Questions
==========================

.. note::

    This FAQ is a work in progress. We will add lots of questions and not answer them right away just to remember
    what is often asked. If you stumble across an unanswered question please write a mail to the mailing-list or
    join the #doctrine channel on Freenode IRC.

Database Schema
---------------

How do I set the charset and collation for MySQL tables?
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

You can't set these values inside the annotations, yml or xml mapping files. To make a database
work with the default charset and collation you should configure MySQL to use it as default charset,
or create the database with charset and collation details. This way they get inherited to all newly
created database tables and columns.

Entity Classes
--------------

I access a variable and its null, what is wrong?
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

If this variable is a public variable then you are violating one of the criteria for entities.
All properties have to be protected or private for the proxy object pattern to work.

How can I add default values to a column?
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Doctrine does not support to set the default values in columns through the "DEFAULT" keyword in SQL.
This is not necessary however, you can just use your class properties as default values. These are then used
upon insert:

.. code-block:: php

    class User
    {
        const STATUS_DISABLED = 0;
        const STATUS_ENABLED = 1;

        private $algorithm = "sha1";
        private $status = self:STATUS_DISABLED;
    }

.

Mapping
-------

Why do I get exceptions about unique constraint failures during ``$em->flush()``?
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Doctrine does not check if you are re-adding entities with a primary key that already exists
or adding entities to a collection twice. You have to check for both conditions yourself
in the code before calling ``$em->flush()`` if you know that unique constraint failures
can occur.

In `Symfony2 <http://www.symfony.com>`_ for example there is a Unique Entity Validator
to achieve this task.

For collections you can check with ``$collection->contains($entity)`` if an entity is already
part of this collection. For a FETCH=LAZY collection this will initialize the collection,
however for FETCH=EXTRA_LAZY this method will use SQL to determine if this entity is already
part of the collection.

Associations
------------

What is wrong when I get an InvalidArgumentException "A new entity was found through the relationship.."?
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

This exception is thrown during ``EntityManager#flush()`` when there exists an object in the identity map
that contains a reference to an object that Doctrine does not know about. Say for example you grab
a "User"-entity from the database with a specific id and set a completely new object into one of the associations
of the User object. If you then call ``EntityManager#flush()`` without letting Doctrine know about
this new object using ``EntityManager#persist($newObject)`` you will see this exception.

You can solve this exception by:

* Calling ``EntityManager#persist($newObject)`` on the new object
* Using cascade=persist on the association that contains the new object

How can I filter an association?
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Natively you can't filter associations in 2.0 and 2.1. You should use DQL queries to query for the filtered set of entities.

I call clear() on a One-To-Many collection but the entities are not deleted
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

This is an expected behavior that has to do with the inverse/owning side handling of Doctrine.
By definition a One-To-Many association is on the inverse side, that means changes to it
will not be recognized by Doctrine.

If you want to perform the equivalent of the clear operation you have to iterate the
collection and set the owning side many-to-one reference to NULL as well to detach all entities
from the collection. This will trigger the appropriate UPDATE statements on the database.

How can I add columns to a many-to-many table?
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

The many-to-many association is only supporting foreign keys in the table definition
To work with many-to-many tables containing extra columns you have to use the
foreign keys as primary keys feature of Doctrine introduced in version 2.1.

See :doc:`the tutorial on composite primary keys for more information<../tutorials/composite-primary-keys>`.


How can i paginate fetch-joined collections?
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

If you are issuing a DQL statement that fetches a collection as well you cannot easily iterate
over this collection using a LIMIT statement (or vendor equivalent).

Doctrine does not offer a solution for this out of the box but there are several extensions
that do:

* `DoctrineExtensions <http://github.com/beberlei/DoctrineExtensions>`_
* `Pagerfanta <http://github.com/whiteoctober/pagerfanta>`_

Why does pagination not work correctly with fetch joins?
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Pagination in Doctrine uses a LIMIT clause (or vendor equivalent) to restrict the results.
However when fetch-joining this is not returning the correct number of results since joining
with a one-to-many or many-to-many association multiplies the number of rows by the number
of associated entities.

See the previous question for a solution to this task.

Inheritance
-----------

Can I use Inheritance with Doctrine 2?
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
Yes, you can use Single- or Joined-Table Inheritance in Doctrine 2.

See the documentation chapter on :doc:`inheritance mapping <inheritance-mapping>` for
the details.

Why does Doctrine not create proxy objects for my inheritance hierarchy?
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

If you set a many-to-one or one-to-one association target-entity to any parent class of
an inheritance hierarchy Doctrine does not know what PHP class the foreign is actually of.
To find this out it has to execute a SQL query to look this information up in the database.

EntityGenerator
---------------

Why does the EntityGenerator not do X?
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

The EntityGenerator is not a full fledged code-generator that solves all tasks. Code-Generation
is not a first-class priority in Doctrine 2 anymore (compared to Doctrine 1). The EntityGenerator
is supposed to kick-start you, but not towards 100%.

Why does the EntityGenerator not generate inheritance correctly?
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Just from the details of the discriminator map the EntityGenerator cannot guess the inheritance hierarchy.
This is why the generation of inherited entities does not fully work. You have to adjust some additional
code to get this one working correctly.

Performance
-----------

Why is an extra SQL query executed every time I fetch an entity with a one-to-one relation?
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

If Doctrine detects that you are fetching an inverse side one-to-one association
it has to execute an additional query to load this object, because it cannot know
if there is no such object (setting null) or if it should set a proxy and which id this proxy has.

To solve this problem currently a query has to be executed to find out this information.

Doctrine Query Language
-----------------------

What is DQL?
~~~~~~~~~~~~

DQL stands for Doctrine Query Language, a query language that very much looks like SQL
but has some important benefits when using Doctrine:

-  It uses class names and fields instead of tables and columns, separating concerns between backend and your object model.
-  It utilizes the metadata defined to offer a range of shortcuts when writing. For example you do not have to specify the ON clause of joins, since Doctrine already knows about them.
-  It adds some functionality that is related to object management and transforms them into SQL.

It also has some drawbacks of course:

-  The syntax is slightly different to SQL so you have to learn and remember the differences.
-  To be vendor independent it can only implement a subset of all the existing SQL dialects. Vendor specific functionality and optimizations cannot be used through DQL unless implemented by you explicitly.
-  For some DQL constructs subselects are used which are known to be slow in MySQL.

Can I sort by a function (for example ORDER BY RAND()) in DQL?
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

No, it is not supported to sort by function in DQL. If you need this functionality you should either
use a native-query or come up with another solution. As a side note: Sorting with ORDER BY RAND() is painfully slow
starting with 1000 rows.

A Query fails, how can I debug it?
----------------------------------

First, if you are using the QueryBuilder you can use
``$queryBuilder->getDQL()`` to get the DQL string of this query. The
corresponding SQL you can get from the Query instance by calling
``$query->getSQL()``.

.. code-block:: php

    <?php
    $dql = "SELECT u FROM User u";
    $query = $entityManager->createQuery($dql);
    var_dump($query->getSQL());

    $qb = $entityManager->createQueryBuilder();
    $qb->select('u')->from('User', 'u');
    var_dump($qb->getDQL());