[Python] django.db.utils.OperationalError: (1071, 'Specified key was too long; max key length...

Discussão em 'Python' iniciado por Stack, Maio 8, 2025.

  1. Stack

    Stack Membro Participativo

    My model:

    class Course(models.Model):
    language = models.ForeignKey(Language)
    name = models.CharField(max_length=50, unique=True, default='course')
    title = models.CharField(max_length=1024, default='no title')
    foreign_title = models.CharField(max_length=1024, default='no title', blank=True)
    header = models.CharField(max_length=1024, default='', blank=True)
    description = models.TextField(null=True, blank=True)

    def __str__(self):
    return self.title

    def __unicode__(self):
    return u'%s' % self.title


    I am add "unique_together":

    class Course(models.Model):
    language = models.ForeignKey(Language)
    name = models.CharField(max_length=50, unique=True, default='course')
    title = models.CharField(max_length=1024, default='no title')
    foreign_title = models.CharField(max_length=1024, default='no title', blank=True)
    header = models.CharField(max_length=1024, default='', blank=True)
    description = models.TextField(null=True, blank=True)

    class Meta:
    unique_together = ['language', 'name', 'title']

    def __str__(self):
    return self.title

    def __unicode__(self):
    return u'%s' % self.title


    In-migration time getting the error:

    django.db.utils.OperationalError: (1071, 'Specified key was too long; max key length is 767 bytes')


    My DB is: mysql Ver 15.1 Distrib 10.0.17-MariaDB, for debian-linux-gnu (x86_64) using readline 5.2

    I tried to increase the length of the index mysql:

    MariaDB [(none)]> set global innodb_file_format = BARRACUDA;
    Query OK, 0 rows affected (0.00 sec)

    MariaDB [(none)]> set global innodb_large_prefix = ON;
    Query OK, 0 rows affected (0.00 sec)


    But this is still not enough:

    django.db.utils.OperationalError: (1071, 'Specified key was too long; max key length is 3072 bytes')


    The problem index length. How to specify the length limit Django index?

    Continue reading...

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