Re: How is MySQL syntax for a table changed if I had a ManyToManyField?

[mottaz hejaze]

for many to many relationships between two tables .. you can make a third table that only contains the id fields ftom both tables , then you can make a third model for this table

On Fri, 13 Jul 2018, 22:24 , <lissandr...@gmail.com> wrote:

I tried for hours to get django's migrate/makemigrations function work but miserably couldn't so I created my tables in MySQL. Now I'm trying to add a ManyToManyField between 2 models but am not sure how the MySQL syntax is supposed to look like.

This is my current code:

from django.db import models

class Publication(models.Model):

    title = models.CharField(max_length=30)

class Article(models.Model):

    headline = models.CharField(max_length=100)

and I can create a table as follows in MySQL:

CREATE TABLE publication ( 

    title varchar(30)

);

CREATE TABLE Article (

    headline varchar(100),

);

I need to add the ManyToManyField like so: 

class Article(models.Model):

    headline = models.CharField(max_length=100)

    publications = models.ManyToManyField(Publication)

I'm really running low on time, could someone assist me with what the MySQL code is supposed to look like? I will be permanently in your debt.

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[Gerald Brown]

When looking at my database it has the 3rd table for the ManyToMany with the following:

1. ID auto-generated,

2. Table1.ID

3. Table2.ID. 

All fields will be integers.

The 3rd table will be named Table1_Table2 or something like that.

I noticed in your code below that you do not have an ID field on any table.  I believe this is required for M2M tables.  Django makemigrations & migrate will generate this for you if not defined in the model.  Django will also create the third table for you with makemigrations/migrate so no need to create it by hand.

What were the problems you were having with makemigrations/migrate?  It is supposed to create the tables for all apps in your project but you can also specify only 1 app if you want to. 

Hope this helps.

On Saturday, 14 July, 2018 07:05 PM, mottaz hejaze wrote:

for many to many relationships between two tables .. you can make a third table that only contains the id fields ftom both tables , then you can make a third model for this table.

To view this discussion on the web visit https://groups.google.com/d/msgid/django-users/CAHV4E-eGQQ3jdwSaa9d9xaxk7rV_Tt-Fqas3OTuhYEYd1%3D8zMA%40mail.gmail.com.