I have a datamodel, let's say: invoices (m:n) invoice_items
and currently I store the invoice total, calculated in PHP by totalling invoice_items, in a column in invoices. I don't like storing derived data as it paves the way for errors later.
How can I create a logical column in the invoices table in MySql? Is this something I would be better handling in the PHP (in this case CakePHP)?
There's something called Virtual Fields in CakePHP which allows you to achieve the same result from within your Model instead of relying on support from MySQL. Virtual Fields allow you to "mashup" various data within your model and provide that as an additional column in your record. It's cleaner than the other approaches here...(no afterFind() hacking).
Read more here: http://book.cakephp.org/view/1608/Virtual-fields
Leo,
One thing you could do is to modify the afterFind() method in your model. This would recalculate the total any time you retrieve an invoice (costing runtime processing), but would mean you're not storing it in the invoices table, which is apparently what you want to avoid (correct if I'm wrong).
Try this:
class Invoice extends AppModel {
// .. other stuff
function afterFind() {
parent::afterFind();
$total = 0;
foreach( $this->data['Invoice']['InvoiceItems'] as $item )
$total += ($item['cost'] * $item['quantity']);
$this->data['Invoice']['total'] = $total;
}
}
I may have messed up the arrays on the hasMany relationship (the foreach line), but I hope you get the jist of it. HTH,
Travis
Either you can return the derived one when you want it via
SELECT COUNT(1) as total FROM invoice_items
Or if invoices can be multiple,
//assuming that invoice_items.num is how many there are per row
SELECT SUM(num) as total FROM invoice_items
Or you can use a VIEW, if you have a certain way you want it represented all the time.
http://forge.mysql.com/wiki/MySQL_virtual_columns_preview
It's not implemented yet, but it should be implemented in mysql 6.0
Currently you could create a view.
Related
I'm very much a beginner when it comes to database relationships hence what I suspect is a basic question! I have two database tables as follows:
Projects
id
company_id
name
etc...
rfis
id
project_id (foreign key is id on the Projects table above)
Number (this is the column I need help with - more below)
question
The relationships at the Model level for these tables are as follows:
Project
public function rfi()
{
return $this->hasMany('App\Rfi');
}
RFI
public function project()
{
return $this->belongsTo('App\Project');
}
What I'm trying to achieve
In the RFI table I need a system generated number or essentially a count of RFI's. Where I'm finding the difficulty is that I need the RFI number/count to start again for each project. To clarify, please see the RFI table below which I have manually created with the the 'number' how I would like it displayed (notice it resets for each new project and the count starts from there).
Any assistance would be much appreciated!
Todd
So the number field depends on the number of project_id in the RFI table. It is exactly the number of rows with project_id plus one.
So when you want to insert a new row, you calculate number based on project_id and assign it.
RFI::create([
'project_id' => $project_id,
'number' => RFI::where('project_id', $project_id)->count() + 1,
...
]);
What I understood is that you want to set the value of the "number" field to "1" if it's a new project and "increment" if it's an existing project. And you want to automate this without checking for it every time you save a new row for "RFI" table.
What you need is a mutator. It's basically a method that you will write inside the desired Model class and there you will write your own logic for saving data. Laravel will run that function automatically every time you save something. Here you will learn more about mutators.
Use this method inside the "RFI" model class.
public function setNumberAttribute($value)
{
if(this is new project)
$this->attributes['number'] = 1;
else
$this->attributes['number']++;
}
Bonus topic: while talking about mutators, there's also another type of method called accessor. It does the same thing as mutators do, but just the opposite. Mutators get called while saving data, accessors get called while fetching data.
How to select a single row on october cms?
How can a simple thing be so complicated here?
I thought it would be something to help us and not to disturb something that is as simple as
SELECT * FROM `engegraph_forms_membros`
Here it's like fighting against demons without a bible, oh god why?
Why make the query difficult for newbie?
I understand you don't speak English natively but you should watch every single one of these videos.
Does the record belong to a model in a plugin? Here are the docs on how to work with models.
You make a plugin, set the database which creates models, and then make components to be ran in your CMS Pages.
In a component.php file you can have something like this: Here I am calling the model class Agreements with use Author\Plugin\Models\Agreements;. This allows me to run a function/method to retrieve all agreements or one agreements using laravel's eloquent collection services.
Lets say we have the ID of a record. Well we can either call on the Agreements model with ::find or with ::where. You will noticed I have two functions that essentially do the same thing. ::find uses the primary key of the models (in my case the id) and will return a singular record. *Note that find can take an array and return a collection of records; like ::where. Using ::where we are going to look for the ID. *Note ::where always returns a collection which is why I have included ->first().
<?php namespace Author\Plugin\Components;
use Session;
use Input;
use Crypt;
use Db;
use Redirect;
use Illuminate\Contracts\Encryption\DecryptException;
use October\Rain\Support\Collection;
use Author\Plugin\Models\Agreements;
class GetAgreement extends \Cms\Classes\ComponentBase
{
public function componentDetails()
{
return [
'name' => 'Get one agreement',
'description' => 'Get an agreement to change or delete it'
];
}
public function onRun() {
$this->page['agreement'] = $this->getWithFindAgreement;
}
public function getWithFindAgreement() {
$id = 1;
$agreement = Agreements::find($id);
return $agreement;
}
public function getWithWhereAgreement() {
$id = 1;
$agreement = Agreements::where($id)->first();
return $agreement;
}
}
If for some reason you aren't working with models, here are the docs to work with Databases. You will have to register the use Db; facade.
Here call the table you want and use ::where to query it. *Note the use of ->first() again.
$users = Db::table('users')->get();
$user = $users->where('id', 1)->first();
There are two simple ways to select a single row:
This will give you the'first' record in the selected recordset.
SELECT top 1 * FROM `engegraph_forms_membros`
This will select all the records that meet the predicate requirement that the value of <columnname> is equal to <value>
SELECT * FROM `engegraph_forms_membros` where <columnname>=<value>
If you select a record where multiple values meet that requirement, then you can (randomly) pick one by combining the solutions...
SELECT top 1 * FROM `engegraph_forms_membros` where <columnname>=<value>
But be aware that without an ORDER BY clause, the underlying data is unordered and prone to change uncontrollably, which is why most people (including your boss) will find the use of 'Top' to be improper for real use.
I try to sum mutliple count fields with JOOQ and a MySQL database.
At the moment my code looks like this:
int userId = 1;
Field<Object> newField = DSL.select(DSL.count()).from(
DSL.select(DSL.count())
.from(REQUIREMENT)
.where(REQUIREMENT.CREATOR_ID.equal(userId))
.unionAll(DSL.select(DSL.count())
.from(REQUIREMENT)
.where(REQUIREMENT.LEAD_DEVELOPER_ID.equal(userId)))
which always returns 2 as newField. But I want know how many times an user is the creator of a requirement PLUS the lead developer of a requirement.
You say "sum over multiple count", but that's not what you're doing. You do "count the number of counts". The solution is, of course, something like this:
// Assuming this to avoid referencing DSL all the time:
import static org.jooq.impl.DSL.*;
select(sum(field(name("c"), Integer.class)))
.from(
select(count().as("c"))
.from(REQUIREMENT)
.where(REQUIREMENT.CREATOR_ID.equal(userId))
.unionAll(
select(count().as("c"))
.from(REQUIREMENT)
.where(REQUIREMENT.LEAD_DEVELOPER_ID.equal(userId)))
);
Alternatively, if you plan to add many more of these counts to the sum, this might be a faster option:
select(sum(choose()
.when(REQUIREMENT.CREATOR_ID.eq(userId)
.and(REQUIREMENT.LEAD_DEVELOPER_ID.eq(userId)), inline(2))
.when(REQUIREMENT.CREATOR_ID.eq(userId), inline(1))
.when(REQUIREMENT.LEAD_DEVELOPER_ID.eq(userId), inline(1))
.otherwise(inline(0))
))
.from(REQUIREMENT);
More details about the second technique in this blog post
i'm trying to do something perhaps a bit too crazy with Eloquent right now, i have a database where i have the following Tables
Crons - (Has Many) - Campaign - (Has Many) - Leads - (Has Many) - Conversions
I need to get all leads from a Cron, that have no entries in the Conversions table in the last X amount of days
I'm thinking of using a Scope on the Cron model but i'm completely stuck on how to proceed from here.
public function scopeWithValidLeads($query) {
return $query->with(['leads' => function($q) {
}]);
}
So i need to get LEADS where the following is true.
A - The leads belong to a campaign associated with the Cron via a Many-To-Many relationship.
B - They have no record in the conversions table Under this specific campaign or if they do, that the lead is older than X amount of days.
You can get your desired result using doesntHave() method like this:
$x = 10; // last 10 days
$crons = Cron::doesntHave('compaign.leads.conversions')
->whereBetween('created_at', [Carbon::now(), Carbon::now()->addDays($x)])
->get();
Querying Relationship Absence: When accessing the records for a model, you may wish to limit your results based on the absence of a relationship. For example, imagine you want to retrieve all blog posts that don't have any comments. To do so, you may pass the name of the relationship to the doesntHave method
UPDATE
As per the updated question conditions, according to my understanding the leads can be obtained by:
$leads = Lead::whereHas('compaign', function($q) use($compaign) {
$q->has('crons')
->where('id', $compaign->id);
// Use the above line if in case of a compaign is to be filtered out
})->doesntHave('conversions')
->whereBetween('created_at', [Carbon::now(), Carbon::now()->addDays($x)])
->get();
Hope this helps!
Circumstances
I have three models/db-tables related with 1:n each: An order has multiple commissions and a commission has multiple commission_positions. Therefore the commission_position has an FK-field containing a commission id. The commission itself has an FK-field containing the id of an order.
Order > Commission > CommissionPositions
Problem
What I need to do now is select all the CommissionPositions having a certain value in the related Order-Model. Obvious solution is to use the Query-Object of CommissionPosition which I extended with a named scope. The named scope looks like this:
class CommissionPositionQuery extends ActiveQuery
{
/**
* Named scope to filter positions of a certain alpha order id
* #param integer $id the alpha order id
* #return \common\models\query\CommissionPositionQuery
*/
public function alphaOrderId($id)
{
//TODO: with not working
$this->with(['commission.order']);
$this->andWhere(['alpha_order_id'=>$id]);
return $this;
}
}
The relation commission is defined on the Commission-Model and working. The second relation order is defined on the commission-model and working as well. The filtered field alpha_order_id is in the Order-Table. Now I execute the query like this:
$filteredPositions = CommissionPosition::find()->alphaOrderId(17)->all();
The scope is called successfully and the where-part is used, but when I check the generated SQL I see no join-statements even though I use the with-method to tell yii to fetch the relation together. The response is 'unknown column alpha_order_id' which makes sense as there is no join to the related tables. This is the generated SQL:
SELECT * FROM `commission_position` WHERE (`alpha_order_id`=17)
What am I missing? Is this a bug of Yii2?
Found the soution myself. The naming changes between Yii1 and Yii2 lead to a little confusion. To prevent others from wasting time here the details:
Yii1
In yii 1 you would join in a relation (exemplary: commission) directly like this:
$query->with = 'commission'
$query->together = true;
Yii2 / difference
When calling the with-method like showed in the question the relation was successfully added to the with-array of the ActiveQuery. However, when executing the query, the join part was missing.
Solution
Seems like the with-method is NOT the way to go. Instead I used the method called joinWith with the following signature:
public function joinWith($with, $eagerLoading = true, $joinType = 'LEFT JOIN')
Now as described in the answer I defined the relation as the first argument ('commission.order') and left the rest as is, because the default values are perfectly fine. Pay attention to the default value of the second parameter. this makes sure the relations are joined in directly!
Voilà...the resulting sql contains the needed joins. One pitfall is to be considered though: Ambigious column namings is of course to be handled by ourselves! Link to the documentation of the method:
http://www.yiiframework.com/doc-2.0/yii-db-activequery.html#joinWith()-detail
If you want a JOIN use:
$this->joinWith(['commission.order']);