# Error when modeling database

**URL:** <https://forum.djangoproject.com/t/error-when-modeling-database/2003>\
**Category:** Using Django\
**Created:** [April 16, 2020, 10:17pm UTC](https://forum.djangoproject.com/t/error-when-modeling-database/2003 "2020-04-16T22:17:24Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![rubenbisneto](https://avatars.discourse-cdn.com/v4/letter/r/da6949/32.png) [@rubenbisneto](https://forum.djangoproject.com/u/rubenbisneto)\
**Post date:** [April 16, 2020, 10:17pm UTC](https://forum.djangoproject.com/t/error-when-modeling-database/2003/1 "2020-04-16T22:17:24Z")

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Hello.

I’m getting an error message while trying to runserver. This is the erro:

django.core.management.base.SystemCheckError: SystemCheckError: System check identified some issues:

ERRORS:  
gcee.CreditosDeEnergia.periodo\_de\_geracao\_do\_credito: (fields.E304) Reverse accessor for ‘CreditosDeEnergia.periodo\_de\_geracao\_do\_credito’ clashes with reverse accessor for ‘CreditosDeEnergia.periodo\_de\_utilizacao\_do\_credito’.  
HINT: Add or change a related\_name argument to the definition for ‘CreditosDeEnergia.periodo\_de\_geracao\_do\_credito’ or ‘CreditosDeEnergia.periodo\_de\_utilizacao\_do\_credito’.  
gcee.CreditosDeEnergia.periodo\_de\_geracao\_do\_credito: (fields.E304) Reverse accessor for ‘CreditosDeEnergia.periodo\_de\_geracao\_do\_credito’ clashes with reverse accessor for ‘CreditosDeEnergia.periodo\_que\_expira\_credito’.  
HINT: Add or change a related\_name argument to the definition for ‘CreditosDeEnergia.periodo\_de\_geracao\_do\_credito’ or ‘CreditosDeEnergia.periodo\_que\_expira\_credito’.  
gcee.CreditosDeEnergia.periodo\_de\_utilizacao\_do\_credito: (fields.E304) Reverse accessor for ‘CreditosDeEnergia.periodo\_de\_utilizacao\_do\_credito’ clashes with reverse accessor for ‘CreditosDeEnergia.periodo\_de\_geracao\_do\_credito’.  
HINT: Add or change a related\_name argument to the definition for ‘CreditosDeEnergia.periodo\_de\_utilizacao\_do\_credito’ or ‘CreditosDeEnergia.periodo\_de\_geracao\_do\_credito’.  
gcee.CreditosDeEnergia.periodo\_de\_utilizacao\_do\_credito: (fields.E304) Reverse accessor for ‘CreditosDeEnergia.periodo\_de\_utilizacao\_do\_credito’ clashes with reverse accessor for ‘CreditosDeEnergia.periodo\_que\_expira\_credito’.  
HINT: Add or change a related\_name argument to the definition for ‘CreditosDeEnergia.periodo\_de\_utilizacao\_do\_credito’ or ‘CreditosDeEnergia.periodo\_que\_expira\_credito’.  
gcee.CreditosDeEnergia.periodo\_que\_expira\_credito: (fields.E304) Reverse accessor for ‘CreditosDeEnergia.periodo\_que\_expira\_credito’ clashes with reverse accessor for ‘CreditosDeEnergia.periodo\_de\_geracao\_do\_credito’.  
HINT: Add or change a related\_name argument to the definition for ‘CreditosDeEnergia.periodo\_que\_expira\_credito’ or ‘CreditosDeEnergia.periodo\_de\_geracao\_do\_credito’.  
gcee.CreditosDeEnergia.periodo\_que\_expira\_credito: (fields.E304) Reverse accessor for ‘CreditosDeEnergia.periodo\_que\_expira\_credito’ clashes with reverse accessor for ‘CreditosDeEnergia.periodo\_de\_utilizacao\_do\_credito’.  
HINT: Add or change a related\_name argument to the definition for ‘CreditosDeEnergia.periodo\_que\_expira\_credito’ or ‘CreditosDeEnergia.periodo\_de\_utilizacao\_do\_credito’.

System check identified 6 issues (0 silenced).

I created my sqlite db using sqlitestudio and my table named as “Creditos\_de\_energia” is desingned as you can see at thepicture bellow:

 ![WhatsApp Image 2020-04-16 at 7.02.35 PM](https://us1.discourse-cdn.com/flex026/uploads/djangoproject/original/2X/a/af5962573641a7dfbe1a83949c2a97c9d77d0d3b.jpeg)

Those 3 fields (2, 3and 12) are foreinkey to the “Periodos” table.

Can I use inside the a table 3 foreingkey fields pointing to another same table?

What is that did wrong?

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<div class="post-metadata">

**Author:** ![KenWhitesell](https://sea2.discourse-cdn.com/flex026/user_avatar/forum.djangoproject.com/kenwhitesell/32/280_2.png) [@KenWhitesell](https://forum.djangoproject.com/u/KenWhitesell)\
**Post date:** [April 16, 2020, 10:45pm UTC](https://forum.djangoproject.com/t/error-when-modeling-database/2003/2 "2020-04-16T22:45:45Z")

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Thank you for posting the error messages, it’s helpful when trying to diagnose problems. However, in the future, also please post the important code - it makes it easier to talk about and address specific issues.

The information you’re looking for can be found at:

- [Foreign Key fields](https://docs.djangoproject.com/en/3.0/ref/models/fields/#foreignkeyhttps://docs.djangoproject.com/en/3.0/ref/models/fields/#foreignkey)
- [Related fields](https://docs.djangoproject.com/en/3.0/ref/models/fields/#django.db.models.ForeignKey.related_name)  
and
- [Following links backward](https://docs.djangoproject.com/en/3.0/topics/db/queries/#following-relationships-backward)