I've created migrations and also their relationships. looks like I'm using polymorphic relations, because in one table, I could have the value of one model or i could have the value of another model. as you might guess, I have something like this
ID Mappable_type Mappable_id value
Mappable_type could be one or many other models. mappable_id will be appropriate id from that model. I needed this because I'm creating dynamic form builder and that's how I designed a database.
Now I need to fetch some records from 5 tables together, so I gotta use joins. the table where I have mappable_type is at the third place from those 5 joins. now What should I do also to only fetch data from these 5 joins that have specific model type that is in that morph table? I'm doing something like that for now:
$final = Dynamic::join('dynamic_properties_values','dynamic_properties_values.dynamic_id','=','dynamic.id')
->join('dynamic_properties_mapping','dynamic_properties_mapping.id','=','dynamic_properties_values.mapping_id')
->where('dynamic_properties_mapping.mappable_type','=','App\Driver')
->get();
As you see, I have written by hand something like
"App\Driver"
. It doesn't matter I have written it by hand or had it saved into a variable and than used it here. WHat really bothers me is that let's say when I was inserting data into these morph tables, Model got saved as "App\Driver". what if I make a mistake and when fetching with joins, I write something like App\Http\Driver? or what If I changed the location of the model itself in my code project?
What's the best practice not to make those kind of errors by the time my project reaches huge amount of users?
Related
I have a scenario like this:
I have User model that has an OneToMany relationships with the Post model.
I have a Hashtag model that has an OneToMany relationships with the Post model.
Recap: ONE user has MANY posts, ONE post belongs to ONE hashtag, ONE hashtag has MANY posts.
I would like to fetch only unique users records of an hashtag.
I'm able to do it in non scalable way (fetching all the posts first and then iterate filtering by user id), but I need to maintain scalability for large record numbers.
Edit: I saw a partial solution in Laravel docs.
Laravel eloquent has a method called unique().
With that method I can specify the parameter which should be unique in query.
In my case figured it out with:
$users = $hashtag->posts->unique('user_id');
But I can't paginate query in this way...
Has anyone a solution for that?
You have to paginate your main model caller.
I don't know exactly if this is can reproduce your actual scenario, but let's see this example:
Let's say you have the model hashtags
So let's say the code could be something like this:
$users = DB::table('hashtags AS tags')
->select('tags.*')
->join('[posts AS post','post.id','=','tags.id')
->distinct()
->paginate(5, ['tags.*']);
I don't know if your query it'll be very accurate, but for this, I believe the best approach it'll be you do a raw query, could look like it'll be costly to your database and the operation, but you can work around this approach indexing and partitioning your database.
Remembering always the eloquent sometimes even when we're building join queries could be more even costly to your database.
Since you're worried about scalability so the best thing could be for too could write a view to fetch all the data with proper indexing and partitioning.
Try to use DISTINCT
$users = $hashtag->posts()->selectRaw('DISTINCT(user_id) AS unique_user_id')->paginate(10);
OR
use groupBy()
$users = $hashtag->posts()->groupBy('name')->select('user_id')->paginate(10);
I have a table for articles and categories, along with a pivot table; I got all related articles within a category. Using
$category = Category::first();
return $category->articles()->paginate(10); // many to many relationship $this->belongsToMany(Article::class, 'article_category');
It returns the right articles, but it is so slow when there are more than 20000 articles in a category. Is there any way to make the query faster?
note: All tables have indexes.
I have face this quite few times.
So far the only solution that I know is TO NOT USE ELOQUENT in COMPLEX QUERY.
You have to change to DB Query Builder.
I assume you are using "whereHas" in your query. Using it will slow down a lot on your queries. If you do use it, change to DB Query with Join methods. It would be a lot faster.
The only problem is that there is no relationship you can use which you have already declared in the model. You have to manually link it back.
But recently I heard they add this relationship feature already in 5.3. But I have not yet check it out.
Hopefully this will solve the problem.
I am porting a Postgres-backed web app to Laravel 4.2, and I can't see a way to utilize the existing eight or so summation views which are built in the psql db. These views preform various aggregation and averaging functions, and as such are properly part of the schema as they illustrate the relationships between the table entities.
Surely someone has had to use db views with the active record style interface of Laravel? How do you go about it?
Your question is about database views and if I'm not wrong then you are talking about the dynamic table that gets created on the fly, for example, in MySql, it's possible to create a View using something like this:
CREATE VIEW students AS SELECT * FROM profiles where type='student' ORDER BY id;
So, it'll allow to query the dynamic table which is the students view here, for example:
select * from students;
This will return the filtered data from students view. So, if I'm right about your question then I think you are able to use Eloquent just like you use for real tables, for example, to create an Eloquent model for students view you can simply create it using something like this:
class ViewStudent extends Eloquent {
protected $table = 'students';
}
So, now you can use this model as usully you may use for other tables, for example;
$students = ViewStudent::all();
It's just the same way. Since you asked for psql so I'm not sure about the syntax of that or how it works in that system but I believe it's possible same way.
specs: PHP 5 with mySQL built on top of Codeigniter Framework.
I have a database table called game and then sport specific tables like soccerGame and footballGame. these sport specific tables have a gameId field linking back to the game table. I have corresponding classes game and soccerGame/footballGame, which both extend game.
When I look up game information to display to the user, I'm having trouble figuring out how to dynamically link the two tables. i'm curious if it's possible to get all the information with with one query. The problem is, I need to query the game table first to figure out the sport name.
if that's not possible, my next thought is to do it with two queries. have my game_model query the game table, then based off the sport name, call the appropriate sport specific model (i.e. soccer_game_model) and get the sport specific info.
I would also pass the game object into the soccer_model, and the soccer_model would use that object to build me a soccerGame object. this seems a little silly to me because i'm building the parent object and then giving it to the extending class to make a whole new object?
thoughts?
thanks for the help.
EDIT:
game table
gameId
sport (soccer, basketball, football, etc)
date
other data
soccerGame table
soccerGameId
gameId
soccer specific information
footballGame table
footballGameId
gameId
football specific information
and so on for other sports
So I need to know what the sport is before I can decide which sport specific table I need to pull info from.
UPDATE:
Thanks all for the input. It seems like dynamic SQL is only possible through stored procedures, something I'm not well versed on right now. And even with them it's still a little messy. Right now I will go the two query route, one to get the sport name, and then a switch to get the right model.
From the PHP side of things now, it seems a little silly to get a game object, pass it to, say, my soccer_game_model, and then have that return me a soccer_game object, which is a child of the original game. Is that how it has to be done? or am I missing something from an OO perspective here?
To extend on Devin Young's answer, you would achieve this using Codeigniter's active record class like so:
public function get_game_by_id($game_id, $table)
{
return $this->db->join('game', 'game.id = ' . $table . '.gameId', 'left')
->where($table . '.gameId', $game_id)
->get('game')
->result();
}
So you're joining the table by the gameId which is shared, then using a where clause to find the correct one. Finally you use result() to return an array of objects.
EDIT: I've added a second table paramater to allow you to pass in the name of the table you can join either soccerGame, footballGame table etc.
If you don't know which sport to choose at this point in the program then you may want to take a step back and look at how you can add that so you do know. I would be reluctant to add multiple joins to all sport tables as you''ll run into issues down the line.
UPDATE
Consider passing the "sport" parameter when you look up game data. As a hidden field, most likely. You can then use a switch statement in your model:
switch($gameValue) {
case 'football': $gameTable = "footballGame"; break;
case 'soccer': $gameTable = "soccerGame"; break;
}
Then base your query off this:
"SELECT *
FROM ". $gameTable . "
...etc
You can combine the tables with joins. http://www.w3schools.com/sql/sql_join.asp
For example, if you need to get all the data from game and footballGame based on a footballGameId of 15:
SELECT *
FROM footballGame a
LEFT OUTER JOIN game b ON a.id = b.gameId
WHERE footballGameId = 15
Check this Stack Overflow answer for options on how to do it via a standard query. Then you can turn it into active record if you want (though that may be complicated and not worth your time if you don't need DB-agnostic calls in your app).
Fow what it's worth, there's nothing wrong with doing multiple queries, it just might be slower than an alternative. Try a few options, see what works best for you and your app.
For example I have the following tables in my database:
People
Groups
And in the People table I have the following columns:
Name
Birthdate
Group
In the Groups table I have the following columns:
Name
Colour
Now I want to fetch results from my database to make a list of all the People.
So I would use this:
$this->set('people', $this->Person->find("all"));
And obviously in my view I would loop through the returned array and display it. Now I also want to find out for each person in the list what Colour and Group name they are (retrieved from the groups table).
How would I go about this in CakePHP.
First make sure your model relationships are defined. Second, you might want to consider using "id" fields for your related tables (I assume you did and maybe just did not include them in your original questions table definitions).
And yes, run debug($this->Person->find("all")) as Elwhis noted to see what your array is dumping out.
And if this is a mission critical application, be sure to use containable instead of recursive to prevent taxing queries to your db.
You have to set the recursive attribute. But I guess it should work with the default value. Put this line in your controller debug($this->Person->find("all")) and check whether the data doesn't already contain you desired group information.
If not, try setting $this->Person->recursive = 1; before calling the find() function
For more information about recursive: http://book.cakephp.org/view/1063/recursive