this post was submitted on 16 Jun 2024
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understanding many2one, one2many and many2many relationshit (lemmy.ca)
submitted 4 months ago by kionite231@lemmy.ca to c/programming@programming.dev
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Hii,

I am new to database thing so I am trying to wrap my head around it.

  1. many2one: so in this relationship you will have more than one record in one table which matches to only one record in another table. something like A <-- B. where (<--) is foreign key relationship. so B will have a column which will be mapped to more than one record of A.

  2. one2many: same as many2one but instead now the foreign key constrain will look something like A --> B.

  3. many2many: this one is interesting because this relationship doesn't make use of foreign key directly. to have this relationship between A and B you have to make a third database something like AB_rel. AB_rel will hold values of primary key of A and also primary key of B. so that way we can map those two using AB_rel table.

tell me if I got something wrong :) give me some suggestion <3

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[โ€“] Tja@programming.dev -5 points 4 months ago (1 children)

You also have NoSQL databases, where you can have arrays, embedding and you can often save yourself the CPU hit of joins.

[โ€“] kionite231@lemmy.ca 1 points 4 months ago

I am familiar with NoSQL databases. they are generally easy to use and don't require much effort. however we use postgresql where I am doing my internship. It's a Odoo based company and Odoo uses postgresql as backed database.