Django插入或更新记录

Question

插入有效，但输入多个数据，当我尝试更新时插入两个数据时，它不会更新记录

我只希望当数据已经在数据库中有记录时，只需更新。如果没有，它将插入

def GroupOfProduct(request):
    global productOrderList
    relatedid_id = request.POST.get("relatedid")
    groups = ProductRelatedGroup(id=id)
    productOrderList=[]
    try:
        for products_id in request.POST.getlist("product"):
            products = Product(id=products_id)
            insert_update_groupofproduct = ProductRelatedGroupAndProduct(
                product = products
            )
            insert_update_groupofproduct.save()
    except ProductRelatedGroupAndProduct.DoesNotExist:
        for products_id in request.GET.getlist("relatedid"):
            products = Product(id=products_id)
            insert_update_groupofproduct = ProductRelatedGroupAndProduct.objects.get(id=products)
            insert_update_groupofproduct.product = products
            insert_update_groupofproduct.save()
    return redirect(relatedgroup)

这是我的模特

class Product(models.Model):
    product = models.CharField(max_length=500)

class ProductRelatedGroup(models.Model):
    category = models.CharField(max_length=500, blank=True)

class ProductRelatedGroupAndProduct(models.Model):
    productrelatedgroup = models.ForeignKey(ProductRelatedGroup,on_delete=models.SET_NULL, null=True, blank=True,verbose_name="Product Related Group")
    product = models.ForeignKey(Product,on_delete=models.SET_NULL, null=True, blank=True,verbose_name="Product")

更新

我尝试了这个，插入工作正常，但更新不起作用

def GroupOfProduct(request):
    global productOrderList
    groups = ProductRelatedGroup(id=id)

    idproduct = request.POST.get('relatedid')

    if ProductRelatedGroupAndProduct.objects.filter(id=idproduct).exists():
        print("update")
        for products_id in request.GET.getlist("relatedid"):
                products = Product(id=products_id)
                insert_update_groupofproduct = ProductRelatedGroupAndProduct.objects.get(id=products)
                insert_update_groupofproduct.product = products

                insert_update_groupofproduct.save()
                return redirect(relatedgroup)
    else:

        productOrderList = []
        for isa in request.POST.getlist('relatedid'):
            productOrderList.append(isa)
        i = 0
        for i in productOrderList:
            for products_id in request.POST.getlist("product"):
                products = Product(id=products_id)
                insert_update_groupofproduct = ProductRelatedGroupAndProduct(
                    productrelatedgroup=groups,
                    product=products
                )
                insert_update_groupofproduct.save()
            return redirect(relatedgroup)
    return redirect(relatedgroup)

我的程序流程（附图片）

当管理员用户插入数据时（如下所示）

批量插入工作非常好

当我尝试更新时（批量更新）

只更新了一个数据

当我再次尝试插入时（就像这样）

没有结果

插入

<QueryDict: {'csrfmiddlewaretoken': ['F3evgRJwNw4p5XCOVE0qeFhP3gmGG5ay4GBbpoZQg3P5l6TNXHY7KN2lD56s6NCU'], 'relatedid': ['200', '201']}>

这是我的html

{% for relatedgroups in relatedgroups %}
<input type="hidden" name="relatedid" value="{{relatedgroups.id}}">
{% endfor %}
<fieldset class="module aligned ">
        <div class="form-row field-user_permissions">
            <div>
                <div class="related-widget-wrapper">
                    <select name="product" id="id_user_permissions" multiple class="selectfilter" data-field-name="Product" data-is-stacked="0">
                        {% for relatedgroups in relatedgroups %}
                        <option value="{{relatedgroups.product.id}}" selected>{{relatedgroups.product}}</option>
                        {% endfor %}
                        {% for product in products %}
                        <option value="{{product.id}}">{{product.id}}-{{product}}</option>
                        {% endfor %}
                    </select>
                </div>
                </div>
        </div>
</fieldset>

当数据被选中或数据库中已有数据时，它将显示在所选产品框中

Answer 1

我们需要首先使用related_ids（已选择的产品ID）从ProductRelatedGroupAndProduct中删除所有记录，然后使用product_ids（已选择的产品ID）再次进入ProductRelatedGroupAndProduct

为什么我们需要删除

如果要从所选列表中删除产品，则更新不会删除该关系。为了从所选列表中删除该产品，我们需要删除该关系（而不是该产品）

def GroupOfProduct(request):
    related_ids = request.POST.getlist('relatedid')
    product_ids = request.POST.getlist("product")

    # delete the existing ProductRelatedGroupAndProduct entries
    for product_id in related_ids:
        product = Product.objects.filter(id=product_id).first()
        obj = ProductRelatedGroupAndProduct.objects.get(product = product)
        obj.delete()

    # create new records in ProductRelatedGroupAndProduct with the selected product_ids
    for product_id in product_ids:
        product = Product.objects.filter(id=product_id).first()
        obj = ProductRelatedGroupAndProduct(
            product = product,
        )
        obj.save()

Answer 2

请使用update_or_create方法。如果存在数据，则使用此方法更新新插入的详细信息。 参考： https://www.kite.com/python/docs/django.db.models.QuerySet.update_or_createhttps://djangosnippets.org/snippets/1114/

def GroupOfProduct(request):
    group_id = request.POST.get('group')
    groups = ProductRelatedGroup(id=group_id)
    idproduct = request.POST.get('product')
    for products_id in request.POST.getlist("product"):
        products = Product(id=products_id)
    ProductRelatedGroupAndProduct.objects.update_or_create(id=idproduct,defaults={'product':products,'productrelatedgroup':groups})  
    return redirect(relatedgroup)