Question

我有django 1.10项目。我有一个模型反馈：

/// <summary>
    /// Represents an activity log filter options.
    /// </summary>
    public class ActivityLogFilterOptions
    {
        /// <summary>
        /// Gets or sets the device ids to which the activity logs to be fetched.
        /// </summary>
        public string DeviceIds { get; set; }

        /// <summary>
        /// Gets or sets the start date for of the search.
        /// </summary>
        [DateTimeCompare("ToDate",
            ValueComparison.IsLessThan, ErrorMessage = "From date must be earlier than end date.")]
        public DateTime? FromDate { get; set; }

        /// <summary>
        /// Gets or sets the end date for the search.
        /// </summary>
        [DateTimeCompare("FromDate",
            ValueComparison.IsGreaterThan, ErrorMessage = "To date must be later than from date.")]
        public DateTime? ToDate { get; set; }

        /// <summary>
        /// Gets or set the page index.
        /// </summary>
        [Required]
        [Range(0, int.MaxValue)]
        public int? PageIndex { get; set; }

        /// <summary>
        /// Gets or sets the maximum record count per page.
        /// </summary>
        [Required]
        [Range(1, short.MaxValue)]
        public int? RecordsPerPage { get; set; }

        /// <summary>
        /// Gets or sets the activity log groups.
        /// </summary>
        public string Groups { get; set; }
    }

此模型存在且DB表的列公司由公司项目的键填充。

现在我需要在模型中添加一些新字段：

class Feedback(FirstMixin, SecondMixin, models.Model):
    company = models.OneToOneField(
        verbose_name='Company',
        to=Company,
        related_name='feedback'
    )

此字段应存储公司的自定义名称。

在迁移过程中，如何使此字段的值与相关公司名称相同？我应该更改迁移的代码，还是有一些方法可以在模型中定义它？

Answer 1

是，您要更改已创建的迁移文件。尝试使用以下解决方案

from django.db import migrations, models
from django.db.models import F

def migrate_custome_name(apps, schema_editor):
    Feedback = apps.get_model("app_name","Feedback")
    Feedback.objects.all().update(
        custom_name=F('company'))

class Migration(migrations.Migration):

    dependencies = [
        ------
    ]

    operations = [
        migrations.AddField(
            model_name='feedback',
            name='custom_name',
            -- your code --
        ),
        migrations.RunPython(migrate_custome_name), # Add this function to migrate data
    ]

希望这会对你有所帮助。

Answer 2

您可以使用数据迁移，请参阅此处的Django文档：https://docs.djangoproject.com/en/1.10/topics/migrations/#data-migrations。在对表格应用更改后，您需要运行设置Feedback.custom_name = Feedback.company 的操作。

在创建同一模型的新字段时，复制现有字段中的值

2 个答案: