This is more of a best practices question. I am making a game where factions can upgrade their technology for their faction. So I have a faction table which stores the faction name and id and a tech_upgrades table which stores the possible tech upgrades along with their costs. Then I have another table which stores the progress each faction has made towards their tech upgrades which is the faction_tech_upgrades table. So there should be a row in faction_tech_upgrades for every combination of faction and tech_upgrade. This kind of looks like a pivot table with extra data similar to https://laravel.com/docs/9.x/eloquent-relationships#retrieving-intermediate-table-columns
My dilemma involves how to set up the eloquent relationships. My gut says to use option 1 but just wanted to make sure I'm not setting these up poorly. So any advice on best practices is appreciated. Here are the 2 options I think make sense.
Option 1:
Create a model for faction_tech_upgrades. Then set up a one to many relationship between factions and faction_tech_upgrades, and set up a one to many relationship between tech_upgrades and faction_tech_upgrades. The reasoning here is that the faction_tech_upgrades table is functioning as more than just a pivot table so maybe making a model for it makes sense, as it might be easier to work with in terms of updating and querying the table.
Option 2:
Set faction_tech_upgrades up a as a pivot table and use the above link to get the data from that table. And use https://laravel.com/docs/9.x/eloquent-relationships#updating-a-record-on-the-intermediate-table to update the table.
factions columns
id,
name,
color,
created_at,
updated_at
tech_upgrades columns
id,
name,
description,
class,
order,
type,
gold_cost,
iron_cost,
wood_cost,
emerald_cost,
pink_tourmaline_cost,
turquoise_cost,
created_at,
updated_at
faction_tech_upgrades columns
id,
faction_id,
tech_upgrade_id,
unlocked,
gold_contributed,
iron_contributed,
wood_contributed,
emerald_contributed,
pink_tourmaline_contributed,
turquoise_contributed,
created_at,
updated_at
Any advice or other options appreciated.
If you have more than 2-3 extra fields in a pivot table, its better to create an another model and make one to many relationship as you describe in option one. It will will be easy to insert and update data. But if you follow the Laravel pivot table naming convention you will get extra benefit for easy access of the data.
Related
Hello I am working with Laravel,
I have to create two simple models, let's say Stores and Books.
Stores can have one or multiple Books and Books can belong to many Stores.
Of course I will use a many to many relationship, with a pivot table.
Books the can have different prices depending the store.
I think a separate table can only complicate things, in my mind the pivot table associating books and stores should have a price column, but pivot tables only contains store_id and book_id.
Should I create a book_prices and associate it with books and to stores? What is the best approach?
You are free and able to set other attributes on your pivot table. You can read more about it in the docs.
https://laravel.com/docs/9.x/eloquent-relationships#retrieving-intermediate-table-columns
You have to define the relationship accordingly, the following should clarify how this works. In this example you use the many-to-many relationship and add the price column to every retrieved pivot model.
public function books()
{
return $this->belongsToMany(Book::class)
->withPivot('price')
}
For example, you are able to access the pivot column in a loop like this
foreach ($shop->books as $book)
{
echo $book->pivot->price;
}
You can define additional columns for your pivot table in the migration for the pivot table, and then when defining the relationship use withPivot to define the additional columns so they come through in the model:
return $this->belongsToMany(Book::class)->withPivot('price');
(Adapted from the Laravel documentation, see https://laravel.com/docs/9.x/eloquent-relationships#retrieving-intermediate-table-columns)
Depends on the complexity of your case, but yes, you have two options for it. Let's say that the pivot table is called as book_store:
Directly adds price column to book_store. This is obviously the simpler option. The drawbacks are:
The history of the price changes isn't logged. You'll have to create another table for logging if you want to keep this history information.
Changes made to price will directly change the price of the related book_store record. Meaning that a price is being updated "live" e.g users cannot update the price now but "publish" it some time later just like this example in the doc.
Create a new, different table to store the price. This may seems relatively more complex, but it may also be more future-proof.
Basically, you get 2 things that you miss in the first option above.
Don't think too much about book_store being a pivot table. One way to see it is like this: book_store IS a pivot table from books and stores tables viewpoints, but it's also just a normal SQL table which could relate to any other tables using any kind of relationships.
If you want to implement this, make sure to create a primary-key in the book_store table.
Alast, it all depends on what you need. Feel free to ask if you need more insight about this. I hope this helps.
I have a table customers with the fields id, name and so on.
One table doctors with the fields id, name.
Then there is one table subject_areas which has all subject areas which a doctor can have. The fields are id, text.
So, each doctor can have multiple subject areas. There is one pivot table doctor_subject which is a belongsToMany relation.
Here is my problem: A customer can have multiple doctors, but only for a specific subject area. I tried it with a new table customer_doctor with the fields id, customer_id and doctor_subject_id. But how do i map this in Eloquent?
Issue was in relation between tables. After chat clarification this came out as solution:
Html form is written in a way that customer first choose doctor, then depending on selection choose several of his available areas.
In that scenario customer needn't to be related to areas directly and should be related to areas only over relation with doctor.
Also as side note, if needed deeper relations, models on pivot tables could be created and used as well.
I have to design data warehouse model and ETL process for class at my University. My data warehouse has to store opinions / comments about a product, each record should consist of:
comment text (String)
product score ({0, 0.5, … , 4.5, 5})
comment author (String)
comment date (Date)
product recommendation ({Yes, No})
comment up votes (Int)
comment down votes (Int)
product pros (many Strings, e.g {price, design, durability, … }) and its count
product cons (many Strings, e.g {too loud, too heavy, price, … }) and
its count
In addition data warehouse should store information about product:
product category
product brand
product model
I want to create data warehouse model first, but I have problem with storing product pros and cons as it is many-to-many relationship. In normal relational database I would simply create associative table, but here I am not sure how to proceed, after all I don’t want to normalize facts table.
I am considering 3 approaches, first, which I presented in diagram below. I used bridge table method (though, I don’t know if correctly) to get rid of many-to-many relationship. I don’t know how it will impact querying performance.
Second approach I may use is boolean column method. In PROS and CONS table I can create a column for each possible value, but there can be up to 100 different pros or cons. Also number of possible pros or cons is not constant in time. Authors in their comments can list new pros or cons (that’s how it works in data source), but I can’t add new columns (I shouldn’t change data in data warehouse).
Third approach I am considering, is to keep pros in PROS table but in 1 column, where values will be separated using commas or some other delimiter e.g. “price, design, color”. It keeps things simple but hard to analyze or slice & dice.
Which approach should I use in this situation? Which is better for loading data into data warehouse, because form data source I will get all the comments and I want to only load comments that are new since last loading?
What I think is, if we can get your first option little bit modified to than what you have said here, it would be the best as I understand.
in your image you have provided, having the Pros_Bridge_Detail table is fine. The rest need to be changed.
you can remove the pros_Bridge table that holds just the count. you can actually add that column to your COMMENT fact table you have up there. That would be more efficient and easy when it comes to queries rather than querying in many tables.
you said you have many areas to give pros like price, design, durability etc. Lets put those stuff into a separate dimension.
Add a new column to your Pros_Bridge_Detail table to hold the ID of the newly created Dimension that holds the product pro types (Design, durability etc).
Now, once you add a product Pro, the Pros_Bridge_Detail table will have the pros the user give and also hold the value of regarding what the pro is given via the ID of the new dimension.
Also don't forget to store the Comment ID as well in Pros_Bridge_Detail table as that will be your link (FK) to Comments fact table you have.
Same can be done to Cons as well.
Hope you understand what I just explained and hope it helps. let know if you have any issues.
I want to know how to handle mysql tables created with constraints in joomla.
for a example,
theater_table
id , name, description, image, address, tel, fax ,email
theater_facility_table
id, theater_id, facility_id
facility_table
id, name, description, image
Facility table already filled with data and id is the primary key. When creating a theater I am adding facilities to it. I created facility and theater JTables.
Do I have to create theater_facility JTable too?
Using theater Model class how I insert data to theater_facility table. I know I can insert data after theater stored successfully creating and calling storeTheaterFacility() method where it contains insert query to save required information. But I feel it can't be a good method to do so. Please help me to solve this.
Depending on how you implemented the theater - facility relationship, you can handle insering new data in different parts of your code. I mean, if for example your JTable class (the one that loads theaters) is loading/saving the theater-facilities relationship too, then the same class should delete it.
May be you can take a look at other components (for example, com_content, which relates an article to a category, or K2, where you can have multiple tags related to multiple "items"(articles)), so you can take a look on how do these components handle these kind of relationships.
Another important point you shouldn't forget is to update your facility model / table to delete records from the relationship table upon facility deleting.
I hope it helped!
I'm having a hard time designing a relationship with a few models in my project.
The models are: band, musician, instrument
Bands have multiple musicians
Musicians have multiple bands and multiple instruments
That’s all pretty straightforward, but I also need to keep track of what instruments a musician has for a particular band. So in a sense, I guess, bands have multiple instruments via the musicians.
In the tables, I was going to add instrument_id to the bands_musicians linking table, but I need a musician to be able to have multiple instruments for a band, so I was thinking it would need to go in the musicians_instruments table.
What's the best way to set up the relationships with these models?
Thanks for your time!
Musicians would have a one-to-many relationship with both bands and instruments. So create your musicians table and add all of the information relavent to the musicians themselves into that table.
Create an instruments table to hold information about instruments, and do the same for the bands. That will take care of all of your individual items.
Then create something like 'band_assignments' table that just has the id of a band and the id of a musician and links the two together. Create an 'instrument_assignment' table to do the same thing.
Now when you query a musician you can left join all of these tables together to get the data that you need or selectively join on just instruments, just bands, or sort by 'join date' and limit to get the last band they joined or the last instrument they learned.
Basically 5 tables should cover it all.
musicians (musician_id, first_name, last_name)
bands (band_id, name)
instruments (instrument_id, name)
band_instument_assignments (musician_id, band_id, instrument_id, date_played)
As you can see in the edited version above you will have multiple rows in the 'band_instrument_assignments' table--one for each instrument that each user played in each band. You will need to use some GROUP BY and LIMIT clauses to get the data you want, but it should work for you.
See:
How to handle a Many-to-Many relationship with PHP and MySQL
That should give you an idea on how to go about designing your database structure.
someoneinomaha
Maybe you need 4th model, which will cover and union all of her children entities, e.g. called like 'Mus Model'(or whatever you want) and have some methods like:
get_bands()
get_instruments()
get_musicians()
get_instruments_by_musician()
get_musicians_by_band()
get_instruments_by_band()
get band_by_musician()
and so on...It'll provide you needed data and will not brake entities relationships, imho.
I might be a little late to the party here and I am no database expert but I have found that drawing out your DB schema helps immensely. Just make boxes and fill in your table names and columns then draw arrows to define your relationships and it should be a lot clearer as to how you should structure things and whether you need to add a table to join two other tables.
If all else fails, just copy a schema from databaseanswers.org. I'm sure there is one there that would probably help you.