Django form/database error: value too long for type character varying(4)

Question

I'm trying to save a stripe (the billing service) company id [around 200 characters or so] to my database in Django.

The specific error is:

database error: value too long for type character varying(4)

How can I enable Django to allow for longer values?

I saw: value too long for type character varying(N) and: Django fixture fails, stating "DatabaseError: value too long for type character varying(50)"

• my database is already encoded for UTF-8, according to my webhost.

• EDIT : I see that one answer recommends making the column wider. Does that involve modifying the PostgreSQL database?

My specific system is Webfaction, CentOs shared machine, Django running on PostgreSQL. I would really appreciate a conceptual overview of what's going on and how I can fix it.

Solution 1

Yes, make the column wider. The error message is quite clear: your 200 characters are too big to fit in a varchar(4).

First, update your model fields max_length attribute from 4 to a number that you expect will be long enough to contain the data you're feeding it.

Next up you have to update the database column itself as django will not automatically update existing columns.

Here are a few options:

1: Drop the database and run syncdb again. Warning: you will lose all your data.

2: Manually update the column via SQL:

Type in python manage.py dbshell to get into your database shell and type in

ALTER TABLE my_table ALTER COLUMN my_column TYPE VARCHAR(200)

3: Learn and use a database migration tool like django south which will help keep your database updated with your model code.

Solution 2

Using Django 1.11 and Postgres 9.6 I ran into this, for no apparent reason.

I set max_length=255 in the migration file and executed:

manage.py migrate

Then I set the correct length on the Model's max_length and ran another makemigrations and the ran migrate again.

Comments

[Yuji 'Tomita' Tomita]

Yes, make the column wider. Type in python manage.py dbshell to get into your database shell. You can manually modify the table with ALTER TABLE statements, drop the database and run syncdb again, or learn and use a database migration tool like South

[mu is too short]

You could drop the 200 if it isn't a requirement: "There is no performance difference among these three types, apart from increased storage space when using the blank-padded type, and a few extra CPU cycles to check the length when storing into a length-constrained column. While character(n) has performance advantages in some other database systems, there is no such advantage in PostgreSQL"

[James Khoury]

I would +1 this just for the comment "you have to update the database column itself " thats something i often trip up on.

[Yuji 'Tomita' Tomita]

@James Khoury - this answer was your fault! And I thought I could get away with a comment and be on my way. : )