Where to start?

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Hi, im new in DB with experience in programming and i’m trying to develop a aplicaction where the user has a inventory with cards, this cards the user can use it to fight and sell it in a global market, so my idea was to create a poll where all the cards with his especs are and then when a user achieve to get one copy all the info of the card put it in the user document, so now the card have a special id (not _id) and it belongs to the user, but in the card in the poll continue the same.
Any tutorial or documentation that help me with this especific problem.

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Hi @Sergio_Rodrigo_Ortiz_Avina,

Welcome to mongodb community.

So a card is drawed by a user from the “main deck” and than it should belong yo that user and never be drawen again?

In that case I believe you should have a main cards collection and when a user draw it , it moves from that collection to a cards_users collection where you can place a user_id and index it in that collection.

If that needs to be all or nothing operations you may consider transactions.

How many cards can a user draw? If the number is unlimited or high i wouldn’t embed it in the users collection (may create unbounded array issue).

I suggest to read

MongoDB Schema Design Best Practices | MongoDB.

Thanks

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Thanks to answer, and yes the read help me to understand better.
About your answers the user has a inventory there are all the cards he has. From there the user can create a “team” of 3 cards (they need to be in the inventory) and that team is the one the user use to fight.

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And my main concern is about the cards because i want that this are all predefined, so when the user obtain one i only call that object and now become part of the user inventory, so now that cards have a unique key in the user inventory, this because is the user want to sell this object in a global market do it with this id.
To finally the user had a exact copy of the card in his inventory that can modify but this can’t modify the originally card that is in the “cards poll”

5

Ok so duplicate the cards from the main pool to user inventory.

Now weather this inventory is embedded or have another collection with an indexed user_id depands on the size of this amount per user. If a user can have thousands of cards it won’t work embedded. But if it is 10s then it might be ok.

Anyway the top 3 should probably be embedded anyway.

Hope this helps

Pavel