Case-insensitve unique = True

[Mike Dewhirst]

What is the best way to ensure a charfield is case-insensitively unique?

Currently I'm using a query with __iexact=True but I wonder whether
there is a better way.

Thanks

Mike

[Simon Charette]

If you are using PostgreSQL I'd suggest using a CIText field[0] with a unique

constraint[1].

If you are *not* using PostgreSQL your best choice is likely to emulate the

upcoming expression[3] support for UniqueConstraint(Lower('field')) by using

a RunSQL operation that performs the appropriate DDL assuming your backend

supports it.

Best,

Simon

[0] https://docs.djangoproject.com/en/3.0/ref/contrib/postgres/fields/#citext-fields

[1] https://docs.djangoproject.com/en/3.0/ref/models/fields/#unique

[3] https://github.com/django/django/pull/11929

[maninder singh Kumar]

I wonder at that.  When I develop a model does the CharField have to be specified case insensitive at that level.

For instance :  A search can be case insensitive and iexact is the best way.

Maninder Kumar about.me/maninder.s.kumar

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[Mike Dewhirst]

On 24/01/2020 3:20 pm, Simon Charette wrote:
> If you are using PostgreSQL I'd suggest using a CIText field[0] with a
> unique
> constraint[1].

Surely everyone uses PostgreSQL, no?

That [0] is identical in Django 2.2 and it looks like I should migrate
my models.CharField to django.contrib.postgresfield.CICharField

I'm already using [1] in Django 2.2

Thank you Simon you have made my day :-)

Cheers

Mike

>
> If you are *not* using PostgreSQL your best choice is likely to
> emulate the
> upcoming expression[3] support for UniqueConstraint(Lower('field')) by
> using
> a RunSQL operation that performs the appropriate DDL assuming your backend
> supports it.
>
> Best,
> Simon
>
> [0]
> https://docs.djangoproject.com/en/3.0/ref/contrib/postgres/fields/#citext-fields
> [1] https://docs.djangoproject.com/en/3.0/ref/models/fields/#unique
> [3] https://github.com/django/django/pull/11929
>
> Le jeudi 23 janvier 2020 21:36:29 UTC-5, Mike Dewhirst a écrit :
>
> What is the best way to ensure a charfield is case-insensitively
> unique?
>
> Currently I'm using a query with __iexact=True but I wonder whether
> there is a better way.
>
> Thanks
>
> Mike
>
>

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[Mike Dewhirst]

On 24/01/2020 6:12 pm, maninder singh Kumar wrote:
> I wonder at that.  When I develop a model does the CharField have to
> be specified case insensitive at that level.

That is what Simon advised and I think it is exactly what I want.

>
> For instance :  A search can be case insensitive and iexact is the
> best way.

Searching isn't the problem. I don't want duplicate names differing only
in the case and I want that to be enforced at the model level at
instance creation time and also later if the name is edited.

I have been using iexact to "manually" enforce case insensitive-unique
names.

Cheers

Mike


> --
>
> Maninder Kumar
> http://about.me/maninder.s.kumar
>
> <http://about.me/maninder.s.kumar?promo=email_sig>

>
>
>
> On Fri, Jan 24, 2020 at 8:06 AM Mike Dewhirst <mi...@dewhirst.com.au
> <mailto:mi...@dewhirst.com.au>> wrote:
>
> What is the best way to ensure a charfield is case-insensitively
> unique?
>
> Currently I'm using a query with __iexact=True but I wonder whether
> there is a better way.
>
> Thanks
>
> Mike
>
>
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>

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[gaurav jain]

Hi,

I think you can save a processed version of the text and apply a unique constraint. 

If you want save the original text then save the non processed test as well.

Kind regards

Gaurav Jain

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