![\"\"](\"https:\/\/egonlin.com\/wp-content\/uploads\/2022\/04\/\u8bb0\u5f55\u64cd\u4f5c\u4e4b\u589e\u5220\u6539\u67e51.jpg\")
<\/div><\/p>\n\u4e00\u3001\u5355\u8868<\/h2>\n1\u3001 \u6dfb\u52a0\u8bb0\u5f55<\/h3>\n
\u51c6\u5907\u8868<\/p>\n
from django.db import models\n\nclass Book(models.Model):\n title = models.CharField(max_length=20)\n price = models.DecimalField(max_digits=65,decimal_places=5)\n publish = models.CharField(max_length=30)\n pub_date = models.DateTimeField(auto_now_add=True)\n\n def __str__(self):\n return "%s:%s:%s" %(self.id,self.title,self.price)<\/code><\/pre>\n\u6dfb\u52a0\u8bb0\u5f55\u7684\u4e24\u79cd\u65b9\u5f0f<\/p>\n
# \u65b9\u5f0f\u4e00\nobj=Book.objects.create(title="\u8475\u82b1\u5b9d\u5178",price=100,publish="\u82f9\u679c\u51fa\u7248\u793e")\n\n# \u65b9\u5f0f\u4e8c\uff1a\nobj=Book(title="\u4e5d\u9634\u771f\u7ecf",price=100,publish="\u82f9\u679c\u51fa\u7248\u793e")\nobj.save()<\/code><\/pre>\n\u6dfb\u52a0n\u6761\u8bb0\u5f55\u4e3a\u540e\u7eed\u64cd\u4f5c\u505a\u51c6\u5907<\/p>\n
Book.objects.create(title="\u7ea2\u9f99\u68a6",price=300,publish="66\u51fa\u7248\u793e")\nBook.objects.create(title="\u94a2\u5f39\u662f\u600e\u6837\u70bc\u6210\u7684",price=10,publish="\u65b0\u534e\u51fa\u7248\u793e")\nBook.objects.create(title="\u804a\u658b",price=50,publish="77\u51fa\u7248\u793e")\nBook.objects.create(title="\u8001\u5973\u4eba\u4e0e\u6d77\u738b",price=30,publish="33\u51fa\u7248\u793e")\nBook.objects.create(title="\u897f\u6e38\u8bb0",price=43,publish="88\u51fa\u7248\u793e")<\/code><\/pre>\n2\u3001\u5355\u8868\u67e5\u8be2<\/h3>\n
\u67e5\u8be2API<\/p>\n
<1> all(): \u67e5\u8be2\u6240\u6709\u7ed3\u679c\n\n<2> filter(**kwargs): \u5b83\u5305\u542b\u4e86\u4e0e\u6240\u7ed9\u7b5b\u9009\u6761\u4ef6\u76f8\u5339\u914d\u7684\u5bf9\u8c61\n\n<3> get(**kwargs): \u8fd4\u56de\u4e0e\u6240\u7ed9\u7b5b\u9009\u6761\u4ef6\u76f8\u5339\u914d\u7684\u5bf9\u8c61\uff0c\u8fd4\u56de\u7ed3\u679c\u6709\u4e14\u53ea\u6709\u4e00\u4e2a\uff0c\n \u5982\u679c\u7b26\u5408\u7b5b\u9009\u6761\u4ef6\u7684\u5bf9\u8c61\u8d85\u8fc7\u4e00\u4e2a\u6216\u8005\u6ca1\u6709\u90fd\u4f1a\u629b\u51fa\u9519\u8bef\u3002\n\n<4> exclude(**kwargs): \u5b83\u5305\u542b\u4e86\u4e0e\u6240\u7ed9\u7b5b\u9009\u6761\u4ef6\u4e0d\u5339\u914d\u7684\u5bf9\u8c61\n\n<5> order_by(*field): \u5bf9\u67e5\u8be2\u7ed3\u679c\u6392\u5e8f('-id')\n\n<6> reverse(): \u5bf9\u4e14\u53ea\u5bf9order_by\u6392\u5e8f\u7684\u7ed3\u679c\u8fdb\u884c\u7ffb\u8f6c\n\n<8> count(): \u8fd4\u56de\u6570\u636e\u5e93\u4e2d\u5339\u914d\u67e5\u8be2(QuerySet)\u7684\u5bf9\u8c61\u6570\u91cf\u3002\n\n<9> first(): \u8fd4\u56deQuerySet\u96c6\u4e2d\u7684\u7b2c\u4e00\u4e2a\u5bf9\u8c61 \n\n<10> last(): \u8fd4\u56deQuerySet\u96c6\u4e2d\u7684\u6700\u540e\u4e00\u4e2a\u5bf9\u8c61 \n\n<11> exists(): \u5982\u679cQuerySet\u5305\u542b\u6570\u636e\uff0c\u5c31\u8fd4\u56deTrue\uff0c\u5426\u5219\u8fd4\u56deFalse\n\n<12> values(*field): \u8fd4\u56de\u4e00\u4e2aValueQuerySet\u2014\u2014\u4e00\u4e2a\u7279\u6b8a\u7684QuerySet\uff0c\u8fd0\u884c\u540e\u5f97\u5230\u7684\u5e76\u4e0d\u662f\u4e00\u7cfb\u5217\n model\u7684\u5b9e\u4f8b\u5316\u5bf9\u8c61\uff0c\u800c\u662f\u4e00\u4e2a\u53ef\u8fed\u4ee3\u7684\u5b57\u5178\u5e8f\u5217\n\n<13> values_list(*field): \u5b83\u4e0evalues()\u975e\u5e38\u76f8\u4f3c,\u4f46\u8fd4\u56de\u7684\u662f\u4e00\u4e2a\u5143\u7ec4\u5e8f\u5217\n\n<14> distinct(): \u4ece\u8fd4\u56de\u7ed3\u679c\u4e2d\u5254\u9664\u91cd\u590d\u7eaa\u5f55<\/code><\/pre>\n\u793a\u4f8b<\/p>\n
# QuerySet\u6570\u636e\u7c7b\u578b\uff08\u7c7b\u4f3c\u4e8e\u4e00\u4e2a\u5217\u8868\uff0c\u91cc\u9762\u653e\u7740\u4e00\u4e9b\u5bf9\u8c61\uff09\n# 1 \u65b9\u6cd5\u7684\u8fd4\u56de\u503c\u662f\u4ec0\u4e48\n# 2 \u65b9\u6cd5\u7684\u8c03\u7528\u8005\n\n===============\u8c03\u7528\u8005\u4e3a\u7ba1\u7406\u5668\uff0c\u8fd4\u56de\u503c\u4e3a\u4e00\u4e2a\u8bb0\u5f55\u5bf9\u8c61=========\nobj = Book.objects.get(title="\u804a\u658b")\nprint(obj) # \u7ed3\u679c\u4e3a\uff1aBook object (5)\nprint(obj.title)\n# \u82e5\u627e\u4e0d\u5230\u7b26\u5408\u6761\u4ef6\u7684\u8bb0\u5f55\u5219\u62a5\u9519\nBook.objects.get(title="\u8ddfEgon\u5b66\u517b\u732a\u5c0f\u5999\u62db") # \u62a5\u9519\n\n===============\u8c03\u7528\u8005\u4e3a\u7ba1\u7406\u5668\uff0c\u8fd4\u56de\u503c\u4e3aQuerySet=========\n# 1\u3001all\uff1a\nbook_list = Book.objects.all()\nprint(book_list) # \u7ed3\u679c\u662f\u4e00\u4e2aQuerySet\nprint(book_list[0].title)\nfor obj in book_list:\n print(obj.title)\n\n# 2\u3001filter\nbook_list = Book.objects.filter(title="\u804a\u658b") # \u76f8\u5f53\u4e8ewhere\uff0c\u8fd8\u53ef\u4ee5\u4f7f\u7528\u57fa\u4e8e\u53cc\u4e0b\u5212\u7ebf\u7684\u6a21\u7cca\u67e5\u8be2\n\n# 3\u3001exclude\nbook_list = Book.objects.exclude(title="\u804a\u658b") # \u9664\u4e86title="\u804a\u658b"\u4e4b\u5916\u7684\u90fd\u7559\u4e0b\u6765\n\n===============\u8c03\u7528\u8005\u4e3aQuerySet\uff0c\u8fd4\u56de\u503c\u3002\u3002\u3002=========\n# 1\u3001count(): \u8fd4\u56de\u7684\u662f\u6574\u578b\nn = Book.objects.all().count()\nprint(n) # 7\n\n# 2\u3001first()\uff1a\u8fd4\u56de\u7684\u662f\u4e00\u4e2a\u8bb0\u5f55\u5bf9\u8c61 \nobj = Book.objects.all().first()\nprint(obj) \nprint(obj.id) # 1\n\n# 3\u3001last()\uff1a\u8fd4\u56de\u7684\u662f\u4e00\u4e2a\u8bb0\u5f55\u5bf9\u8c61 \nobj = Book.objects.all().last()\nprint(obj) \nprint(obj.id) # 7\n\n# 4\u3001exists()\uff1a\u8fd4\u56de\u7684\u662f\u5e03\u5c14\u503c\nres = Book.objects.filter(title="\u8ddfEgon\u8001\u5e08\u5b66\u7b97\u547d").exists()\nprint(res) # False\n\n# 5\u3001order_by(*field)\uff1a\u8fd4\u56de\u7684\u540c\u6837\u662fQuerySet\nobjs = Book.objects.filter(id__lte=6)\nprint(objs) # QuerySet\nprint(objs.order_by('price','-id')) # \u5148\u6309\u7167price\u5b57\u6bb5\u5347\u5e8f\u6392\uff0c\u82e5price\u76f8\u540c\u5219\u6309\u7167id\u5b57\u6bb5\u964d\u5e8f\u6392\n\n# 6\u3001reverse()\uff1a\u8fd4\u56de\u7684\u540c\u6837\u662fQuerySet \nobjs = Book.objects.all()\n\n\u65e0\u6548\nprint([obj.id for obj in objs])\nprint([obj.id for obj in objs.reverse()]) # \u987a\u5e8f\u4e0e\u4e0a\u9762\u4fdd\u6301\u4e00\u81f4\n\n\u6709\u6548\nprint([obj.id for obj in objs.order_by('-id')])\nprint([obj.id for obj in objs.order_by('-id').reverse()]) # \u987a\u5e8f\u5728\u4e0a\u9762\u7684\u6392\u5e8f\u7684\u57fa\u7840\u4e0a\u7ffb\u8f6c\n\n# 7\u3001values(*field): \u8fd4\u56de\u7684\u540c\u6837\u662fQuerySet\nobjs = Book.objects.filter(id__gte=3)\nprint(objs.values("title")) # \u8fd4\u56de\u4e00\u4e2aQuerySet\nprint(objs.values("title")[0]['title']) # \u7ea2\u9f99\u68a6\nprint(objs.values("title").last()['title']) # \u897f\u6e38\u8bb0\n\n# 8\u3001values_list(*field): \u8fd4\u56de\u7684\u540c\u6837\u662fQuerySet \nobjs = Book.objects.filter(id__gte=3)\nprint(objs.values_list("title"))\nprint(objs.values_list("title")[0][0]) # \u7ea2\u9f99\u68a6\nprint(objs.values_list("title").last()[0]) # \u897f\u6e38\u8bb0\n\n# 9\u3001distinct(): \u8fd4\u56de\u7684\u540c\u6837\u662fQuerySet\nBook.objects.all().distinct() # \u8be5\u884c\u4ee3\u7801\u65e0\u610f\u4e49\uff0c\u56e0\u4e3a\u6bcf\u4e00\u6761\u7ed3\u679c\u591a\u4e0d\u662f\u91cd\u590d\u7684\n\n\u6b63\u786e\u7528\u6cd5\u5982\u4e0b\nobjs = Book.objects.all().values("price").distinct()\nprint(objs)<\/code><\/pre>\n\u57fa\u4e8e\u53cc\u4e0b\u5212\u7ebf\u7684\u6a21\u7cca\u67e5\u8be2 <\/p>\n
Book.objects.filter(price__in=[100,200,300])\nBook.objects.filter(price__gt=100)\nBook.objects.filter(price__lt=100)\nBook.objects.filter(price__gte=100)\nBook.objects.filter(price__lte=100)\n\n# \u7b49\u540c\u4e8eBook.objects.filter(id__gte=100,id__lte=200)\n# \u76f8\u5f53\u4e8ewhere price between 100 and 200\nBook.objects.filter(price__range=[100,200]) \n\nBook.objects.filter(title__contains="python")\nBook.objects.filter(title__icontains="python") # \u5ffd\u7565\u5927\u5c0f\u5199\nBook.objects.filter(title__startswith="py")\nBook.objects.filter(title__iendswith="py")\n\nBook.objects.filter(pub_date__lte="2021-02-23 17:51:00")\nBook.objects.filter(pub_date__minute="38")<\/code><\/pre>\n3\u3001\u5355\u8868delete<\/h3>\n
\u5220\u9664delete\uff1a\u8c03\u7528\u8005\u53ea\u80fd\u662fQuerySet\u6216\u8005\u5355\u4e2a\u4e00\u4e2a\u8bb0\u5f55\u5bf9\u8c61<\/p>\n
*# \u6279\u91cf\u5220\u9664
\nobjs = Book.objects.filter(id__in=[1,3,5])<\/em>
\nobjs.delete()<\/em>
\n<\/strong>
\n
\n<\/strong># \u5220\u9664\u5355\u4e00\u8bb0\u5f55
\nobjs = Book.objects.filter(id=6)<\/em>
\nobj=objs[0]<\/em>
\nobj.delete()<\/em>
\n<\/strong>
\n*objs.last().delete()<\/p>\n\u5728 Django \u5220\u9664\u5bf9\u8c61\u65f6\uff0c\u4f1a\u6a21\u4eff SQL \u7ea6\u675f ON DELETE CASCADE \u7684\u884c\u4e3a\uff0c\u6362\u53e5\u8bdd\u8bf4\uff0c\u5220\u9664\u4e00\u4e2a\u5bf9\u8c61\u65f6\u4e5f\u4f1a\u5220\u9664\u4e0e\u5b83\u76f8\u5173\u8054\u7684\u5916\u952e\u5bf9\u8c61\u3002\u4f8b\u5982\uff1a<\/p>\n
b = Blog.objects.get(pk=1)
\n# This will delete the Blog and all of its Entry objects.<\/strong>
\n<\/em>b.delete()<\/p>\n\u8981\u6ce8\u610f\u7684\u662f\uff1a delete() \u65b9\u6cd5\u662f QuerySet \u4e0a\u7684\u65b9\u6cd5\uff0c\u4f46\u5e76\u4e0d\u9002\u7528\u4e8e Manager \u672c\u8eab\u3002\u8fd9\u662f\u4e00\u79cd\u4fdd\u62a4\u673a\u5236\uff0c\u662f\u4e3a\u4e86\u907f\u514d\u610f\u5916\u5730\u8c03\u7528 Entry.objects.delete() \u65b9\u6cd5\u5bfc\u81f4 \u6240\u6709\u7684 \u8bb0\u5f55\u88ab\u8bef\u5220\u9664\u3002\u5982\u679c\u4f60\u786e\u8ba4\u8981\u5220\u9664\u6240\u6709\u7684\u5bf9\u8c61\uff0c\u90a3\u4e48\u4f60\u5fc5\u987b\u663e\u5f0f\u5730\u8c03\u7528\uff1a<\/p>\n
Entry.objects.all().delete()\u3000<\/p>\n
\u5982\u679c\u4e0d\u60f3\u7ea7\u8054\u5220\u9664\uff0c\u53ef\u4ee5\u8bbe\u7f6e\u4e3a:<\/p>\n
pubHouse = models.ForeignKey(to=’Publisher’, on_delete=models.SET_NULL, blank=True, null=True)<\/p>\n
4\u3001\u5355\u8868update<\/h3>\n
\u4fee\u6539update\uff1a\u8c03\u7528\u8005\u53ea\u80fd\u662fQuerySet\uff0c\u8fd4\u56de\u503c\u4e3aint<\/p>\n
objs = Book.objects.filter(id=7)\nrows=objs.update(title="xxx") \nprint(rows)\n\nBook.objects.filter(name='\u8ddfEgon\u5b66\u7b97\u547d').first().update(name='\u5927\u5bb6\u591a\u80fd\u6210\u795e\u4ed9') # \u62a5\u9519<\/code><\/pre>\nupdate()\u65b9\u6cd5\u5bf9\u4e8e\u4efb\u4f55\u7ed3\u679c\u96c6\uff08QuerySet\uff09\u5747\u6709\u6548\uff0c\u8fd9\u610f\u5473\u7740\u4f60\u53ef\u4ee5\u540c\u65f6\u66f4\u65b0\u591a\u6761\u8bb0\u5f55update()\u65b9\u6cd5\u4f1a\u8fd4\u56de\u4e00\u4e2a\u6574\u578b\u6570\u503c\uff0c\u8868\u793a\u53d7\u5f71\u54cd\u7684\u8bb0\u5f55\u6761\u6570\u3002<\/p>\n
\u4e8c\u3001\u591a\u8868<\/h2>\n
\u51c6\u5907\u591a\u5bf9\u591a\u3001\u4e00\u5bf9\u591a\u3001\u4e00\u5bf9\u4e00\u5173\u7cfb\u5982\u4e0b<\/p>\n
from django.db import models\n\nclass Book(models.Model):\n nid = models.AutoField(primary_key=True)\n name = models.CharField(max_length=32)\n price = models.DecimalField(max_digits=5, decimal_places=2)\n publish_date = models.DateField(auto_now_add=True)\n # \u9605\u8bfb\u6570\n # read_num=models.IntegerField(default=0)\n # \u8bc4\u8bba\u6570\n # comment_num=models.IntegerField(default=0)\n\n publish = models.ForeignKey(to='Publish',to_field='nid',on_delete=models.CASCADE)\n authors=models.ManyToManyField(to='Author')\n def __str__(self):\n return self.name\n\nclass Author(models.Model):\n nid = models.AutoField(primary_key=True)\n name = models.CharField(max_length=32)\n age = models.IntegerField()\n author_detail = models.OneToOneField(to='AuthorDatail',to_field='nid',unique=True,on_delete=models.CASCADE)\n\nclass AuthorDatail(models.Model):\n nid = models.AutoField(primary_key=True)\n telephone = models.BigIntegerField()\n birthday = models.DateField()\n addr = models.CharField(max_length=64)\n\nclass Publish(models.Model):\n nid = models.AutoField(primary_key=True)\n name = models.CharField(max_length=32)\n city = models.CharField(max_length=32)\n email = models.EmailField()<\/code><\/pre>\n\u751f\u6210\u7684\u8868\u5982\u4e0b\uff1a<\/p>\n
![\"\"](\"data:image\/svg+xml;base64,PCEtLUFyZ29uTG9hZGluZy0tPgo8c3ZnIHdpZHRoPSIxIiBoZWlnaHQ9IjEiIHhtbG5zPSJodHRwOi8vd3d3LnczLm9yZy8yMDAwL3N2ZyIgc3Ryb2tlPSIjZmZmZmZmMDAiPjxnPjwvZz4KPC9zdmc+\")
<\/div><\/p>\n1\u3001\u6dfb\u52a0\u8bb0\u5f55<\/h3>\n
\u591a\u5bf9\u4e00\u5173\u7cfb\u6dfb\u52a0\uff1aapp01_book\u4e0eapp01_publish<\/p>\n
from app01.models import *\n\n# \u5148\u521b\u5efa\u51fa\u7248\u793e\npublish_obj = Publish.objects.create(name="666\u51fa\u7248\u793e", city="\u4e0a\u6d77")\n\n# \u518d\u521b\u5efa\u4e66\u7c4d\u4e0e\u51fa\u7248\u793e\u5173\u8054\uff0c\u5177\u4f53\u6709\u4e24\u79cd\u65b9\u5f0f\n# \u65b9\u5f0f\u4e00\nBook.objects.create(name="\u8ddfegon\u5b66\u7b97\u547d", price=3, publish=publish_obj)\n\n# \u65b9\u5f0f\u4e8c\nbook_obj = Book(name="\u8ddfegon\u5b66\u98ce\u6c34", price=5)\nbook_obj.publish_id = publish_obj.nid\nbook_obj.save()\n\n# \u601d\u8003\uff1a\nbook_obj.publish\u4e0ebook_obj.publish_id\u662f\u4ec0\u4e48\uff1f<\/code><\/pre>\n\u6e05\u7406\u6389\u591a\u5bf9\u4e00\u7684\u5173\u7cfb<\/p>\n
# \u53ef\u4ee5\u53ea\u5220\u6389\u4e00\u4e2a\u4e66\u7c4d\u5bf9\u8c61\nBook.objects.filter(name="\u8ddfegon\u5b66\u7b97\u547d").delete()\n\n# \u56e0\u4e3a\u7ea7\u8054\u5220\u9664\u7684\u5b58\u5728\uff0c\u6240\u4ee5\u5220\u51fa\u4e00\u4e2a\u7248\u793e\u5bf9\u8c61\uff0c\u5bf9\u5e94\u7684\u4e66\u7c4d\u5bf9\u8c61\u4f1a\u4e00\u5e76\u6e05\u9664\nPublish.objects.filter(name="666\u51fa\u7248\u793e").delete()<\/code><\/pre>\n\u4e00\u5bf9\u4e00\u5173\u7cfb\u6dfb\u52a0\uff08\u4e0e\u591a\u5bf9\u4e00\u4e00\u6837\uff09\uff1aapp01_autor\u4e0eapp01_authordatail<\/p>\n
# \u5148\u521b\u5efa\u4f5c\u8005\u8be6\u60c5\nobj = AuthorDatail.objects.create(telephone=1861131111,birthday="2011-11-11",addr="\u6c34\u5e18\u6d1e")\n\n# \u518d\u521b\u5efa\u4f5c\u8005\u4fe1\u606f\nAuthor.objects.create(name='Egon',age=18,author_detail=obj)<\/code><\/pre>\n\u6e05\u7406\u6389\u4e00\u5bf9\u4e00\u5173\u7cfb\uff08\u540c\u591a\u5bf9\u4e00\u4e00\u6837\uff09<\/p>\n
# \u5efa\u8bae\u5220\u4f5c\u8005\u65f6\u76f4\u63a5\u5220\u9664\u4f5c\u8005\u8be6\u60c5\uff0c\u8fd9\u6837\u4fbf\u7ea7\u8054\u5220\u9664\u4e86\u4f5c\u8005\nAuthorDatail.objects.filter(nid=1).delete()\n\n# \u5982\u679c\u53ea\u5220\u4f5c\u8005\uff0c\u4f5c\u8005\u8be6\u60c5\u5f53\u7136\u8fd8\u662f\u4f1a\u5b58\u5728\u7684\nAuthor.objects.filter(nid=1).delete()<\/code><\/pre>\n\u591a\u5bf9\u591a\u5173\u7cfb\u6dfb\u52a0\uff1aapp01_autor,app01_book_autors,app01_book<\/p>\n
=====\u4e0b\u8ff0\u8bb0\u5f55\u5982\u679c\u5df2\u7ecf\u5b58\u5728\u4e86\u5c31\u4e0d\u7528\u521b\u5efa\u4e86\uff0c\u76f4\u63a5\u8fc7\u6ee4\u51fa\u6765\u7528\u5c31\u53ef\u4ee5\u4e86\uff0c\u5982\u679c\u5220\u6389\u4e86\uff0c\u90a3\u5c31\u91cd\u65b0\u5efa\u4e00\u904d\n# 1\u3001\u6dfb\u52a0\u4f5c\u8005\u53ca\u5176\u8be6\u60c5\nobj = AuthorDatail.objects.create(telephone=1861131111,birthday="2011-11-11",addr="\u6c34\u5e18\u6d1e")\nAuthor.objects.create(name='Egon',age=18,author_detail=obj)\n\nobj = AuthorDatail.objects.create(telephone=1361131111,birthday="2022-12-12",addr="\u76d8\u4e1d\u6d1e")\nAuthor.objects.create(name='Tom',age=18,author_detail=obj)\n\nobj = AuthorDatail.objects.create(telephone=1761131111,birthday="2013-10-10",addr="\u91d1\u5149\u6d1e")\nAuthor.objects.create(name='Jack',age=18,author_detail=obj)\n\n# 2\u3001\u6dfb\u52a0\u4e66\u7c4d\npublish_obj = Publish.objects.create(name="666\u51fa\u7248\u793e", city="\u4e0a\u6d77")\nBook.objects.create(name="\u8ddfegon\u5b66\u7b97\u547d", price=3, publish=publish_obj)\nBook.objects.create(name="\u8ddfegon\u5b66\u98ce\u6c34", price=3, publish_id=publish_obj.nid)\n\n===\u6dfb\u52a0\u4f5c\u8005\u4e0e\u4e66\u7684\u591a\u5bf9\u591a\u5173\u7cfb\n# \u8fc7\u6ee4\u51fa\u4e66\u7c4d\u5bf9\u8c61\nbook_obj1 = Book.objects.filter(name="\u8ddfegon\u5b66\u7b97\u547d").first()\nbook_obj2 = Book.objects.filter(name="\u8ddfegon\u5b66\u98ce\u6c34").first()\n\n# \u8fc7\u6ee4\u51fa\u4f5c\u8005\u5bf9\u8c61\negon = Author.objects.filter(name="egon").first()\ntom = Author.objects.filter(name="Tom").first()\njack = Author.objects.filter(name="Jack").first()\n\n# \u6dfb\u52a0\u5173\u7cfb\nbook_obj1.authors.add(egon,tom,jack)\nbook_obj2.authors.add(egon,jack)\nps: \u4e5f\u53ef\u4ee5\u76f4\u63a5\u4f20id\nbook_obj1.authors.add(1,2,3) # \u6216\u8005\u7528\u5f62\u5f0f*[1,2,3]\n\n\u67e5\u770bapp01_book_authors\u8bb0\u5f55\u5982\u4e0b\n+----+---------+-----------+\n| id | book_id | author_id |\n+----+---------+-----------+\n| 1 | 1 | 1 |\n| 2 | 1 | 2 |\n| 3 | 1 | 3 |\n| 4 | 2 | 1 |\n| 5 | 2 | 3 |\n+----+---------+-----------+<\/code><\/pre>\n\u6e05\u7406\u6389\u591a\u5bf9\u591a\u5173\u7cfb<\/p>\n
# remove\uff1a\u4e0b\u9762\u4e09\u79cd\u65b9\u5f0f\u90fd\u53ef\u4ee5\nbook_obj1.authors.remove(egon,tom)\nbook_obj1.authors.remove(1,2)\nbook_obj1.authors.remove(*[1,2])\n\n\u67e5\u770bapp01_book_authors\u8bb0\u5f55\u5982\u4e0b\n+----+---------+-----------+\n| id | book_id | author_id |\n+----+---------+-----------+\n| 3 | 1 | 3 |\n| 4 | 2 | 1 |\n| 5 | 2 | 3 |\n+----+---------+-----------+\n\n# clear(): \u6e05\u7a7a\u88ab\u5173\u8054\u5bf9\u8c61\u96c6\u5408\nbook_obj2.authors.clear()\n\n\u67e5\u770bapp01_book_authors\u8bb0\u5f55\u5982\u4e0b\n+----+---------+-----------+\n| id | book_id | author_id |\n+----+---------+-----------+\n| 3 | 1 | 3 |\n+----+---------+-----------+\n\n# set(): \u5148\u6e05\u7a7a\u518d\u8bbe\u7f6e\uff0c\u53ea\u80fd\u4f20\u5165\u4e00\u4e2a\u5e8f\u5217\uff0c\u91cc\u9762\u5305\u542b\u8981\u6dfb\u52a0\u7684\u4f5c\u8005\u5bf9\u8c61\u6216\u8005\u4f5c\u8005\u5bf9\u8c61\u7684id\u90fd\u53ef\u4ee5\nbook_obj1.authors.set([egon,2])<\/code><\/pre>\n2\u3001\u67e5\u8be2\u8bb0\u5f55<\/h3>\n1.\u591a\u8868\u67e5\u8be2\u7684\u6cd5\u5219\u63d0\u70bc\u5982\u4e0b<\/h4>\n
\u2022 \u7b2c\u4e00\u6b65\uff1a\u5148\u641e\u6e05\u695a\u662f\u6b63\u5411\u67e5\u8be2\u8fd8\u662f\u53cd\u5411\u67e5\u8be2<\/p>\n
\u5173\u8054\u5b57\u6bb5\u6240\u5728\u7684\u8868\u53ef\u4ee5\u79f0\u4e4b\u4e3a\u6e90\u8868\uff0c\u88ab\u5173\u8054\u7684\u8868\u79f0\u4e4b\u4e3a\u76ee\u6807\u8868\uff0c\u5982\u6b64\uff0c\u6b63\u5411\u53cd\u5411\u4e00\u76ee\u4e86\u7136\u4e86<\/p>\n
\u2022 \u7b2c\u4e8c\u6b65<\/p>\n
*# \u57fa\u4e8e\u5bf9\u8c61\u7684\u67e5\u8be2\u76f8\u5f53\u4e8e\u5b50\u67e5\u8be2\uff08\u5176\u5b9e\u672c\u8d28\u662f\u5206\u6b65\u67e5\u8be2\uff09
\n* \u6b63\u67e5\u7528\u5173\u8054\u5b57\u6bb5
\n* \u53cd\u67e5\u7528\u6a21\u578b\u540d\uff0c\u4f46\u5982\u679c\u53cd\u67e5\u7684\u7ed3\u679c\u6709\u591a\u4e2a\u503c\u5219\u8981\u52a0_set<\/em>
\n<\/strong>
\n# \u57fa\u4e8e\u53cc\u4e0b\u5212\u7ebf\u7684\u67e5\u8be2\u76f8\u5f53\u4e8ejoin\u94fe\u8868<\/strong>
\n* \u6b63\u67e5\u7528\u5173\u8054\u5b57\u6bb5
\n\\<\/em> \u53cd\u67e5\u7528\u6a21\u578b\u540d <\/strong><\/p>\n2.\u57fa\u4e8e\u5bf9\u8c61\u7684\u5b50\u67e5\u8be2<\/h4>\n
\u591a\u5bf9\u4e00\u67e5\u8be2\uff1aapp01_book\u4e0eapp01_publish<\/p>\n
# \u6b63\u5411\u6848\u4f8b\uff1a\u67e5\u8be2\u201d\u8ddfegon\u5b66\u7b97\u547d\u201c\u662f\u54ea\u4e2a\u51fa\u7248\u793e\u51fa\u7248\u7684\nbook_obj=Book.objects.filter(name="\u8ddfegon\u5b66\u7b97\u547d").first()\nprint(book_obj.publish.name) # \u6b63\u5411\u67e5\u8be2\u76f4\u63a5\u7528\u5173\u8054\u5b57\u6bb5\uff0c\u5373publish\u5373\u53ef\n\n# \u53cd\u5411\u6848\u4f8b\uff1a\u67e5\u8be2\u201d666\u51fa\u7248\u793e\u201c\u51fa\u7248\u7684\u6240\u6709\u4e66\u7c4d\npublish_obj = Publish.objects.filter(name="666\u51fa\u7248\u793e").first()\nprint(publish_obj.book_set.all()) # \u53cd\u5411\u67e5\u8be2\u7528\u6a21\u578b\u540d\uff0c\u7ed3\u679c\u6709\u591a\u4e2a\uff0c\u6240\u6709\u8fd8\u6709\u52a0_set\uff0c\u8fd4\u56deQuerySet<\/code><\/pre>\n\u4e00\u5bf9\u4e00\u67e5\u8be2\uff1aapp01_autor\u4e0eapp01_authordatail<\/p>\n
# \u6b63\u5411\u6848\u4f8b\uff1a\u67e5\u8be2\u201dEgon\u201c\u7684\u624b\u673a\u53f7\negon=Author.objects.filter(name="Egon").first()\nprint(egon.author_detail.telephone) # \u6b63\u5411\u67e5\u8be2\u76f4\u63a5\u7528\u5173\u8054\u5b57\u6bb5\uff0c\u5373author_detail\u5373\u53ef\n\n# \u53cd\u5411\u6848\u4f8b\uff1a\u67e5\u8be2\u201dnid=1\u7684\u8be6\u60c5\u4fe1\u606f\u5bf9\u5e94\u7684\u4f5c\u8005\u540d\u5b57\u201c\nobj = AuthorDatail.objects.filter(nid=1).first()\nprint(obj.author.name) # \u53cd\u5411\u67e5\u8be2\u7528\u6a21\u578b\u540d\uff0c\u7ed3\u679c\u53ea\u6709\u4e00\u4e2a\uff0c\u6240\u6709author\u540e\u65e0\u9700\u52a0_set<\/code><\/pre>\n\u591a\u5bf9\u591a\u67e5\u8be2\uff1aapp01_autor,app01_book_autors,app01_book<\/p>\n
# \u6b63\u5411\u6848\u4f8b\uff1a\u67e5\u8be2\u201d\u8ddfegon\u5b66\u7b97\u547d\u201c\u7684\u6240\u6709\u4f5c\u8005\negon = Book.objects.filter(name="\u8ddfegon\u5b66\u7b97\u547d").first()\nprint(egon.authors.all()) # \u6b63\u5411\u67e5\u8be2\u76f4\u63a5\u7528\u5b57\u6bb5authors\u5373\u53ef\uff0c\u800cauthors\u6709\u591a\u4e2a\uff0c\u6240\u4ee5\u9700\u8981\u52a0all()\n\n# \u53cd\u5411\u6848\u4f8b\uff1a\u67e5\u8be2\u201dEgon\u201c\u90fd\u51fa\u4e86\u54ea\u4e9b\u4e66\negon = Author.objects.filter(name="Egon").first()\nprint(egon.book_set.all()) # \u53cd\u5411\u67e5\u8be2\u7528\u6a21\u578b\u540d\uff0c\u7ed3\u679c\u6709\u591a\u4e2a\uff0c\u6240\u6709\u8fd8\u6709\u52a0_set\uff0c\u8fd4\u56deQuerySet<\/code><\/pre>\n3.\u57fa\u4e8e\u53cc\u4e0b\u5212\u7ebf\u7684\u94fe\u8868\u67e5\u8be2<\/h4>\n
\u591a\u5bf9\u4e00\u67e5\u8be2\uff1aapp01_book\u4e0eapp01_publish<\/p>\n
# 1\u3001\u67e5\u8be2\u201d\u8ddfegon\u5b66\u7b97\u547d\u201c\u662f\u54ea\u4e2a\u51fa\u7248\u793e\u51fa\u7248\u7684\n===>\u6b63\u67e5\nres = Book.objects.filter(name="\u8ddfegon\u5b66\u7b97\u547d").values_list("publish__name")\nprint(res) # <QuerySet [('666\u51fa\u7248\u793e',)]>\n\n===>\u53cd\u67e5\nres = Publish.objects.filter(book__name="\u8ddfegon\u5b66\u7b97\u547d").values_list("name","city")\nprint(res) # <QuerySet [('666\u51fa\u7248\u793e', '\u4e0a\u6d77')]>\n\n# 2\u3001\u67e5\u8be2\u201d666\u51fa\u7248\u793e\u201c\u51fa\u7248\u7684\u6240\u6709\u4e66\u7c4d\n===>\u6b63\u67e5\nres = Publish.objects.filter(name="666\u51fa\u7248\u793e").values_list("book__name")\nprint(res) # <QuerySet [('\u8ddfegon\u5b66\u7b97\u547d',), ('\u8ddfegon\u5b66\u98ce\u6c34',)]>\n\n===>\u53cd\u67e5\nres = Book.objects.filter(publish__name="666\u51fa\u7248\u793e").values_list("name")\nprint(res) # <QuerySet [('\u8ddfegon\u5b66\u7b97\u547d',), ('\u8ddfegon\u5b66\u98ce\u6c34',)]><\/code><\/pre>\n\u4e00\u5bf9\u4e00\u67e5\u8be2\uff1aapp01_autor\u4e0eapp01_authordatail<\/p>\n
# 1\u3001\u67e5\u8be2\u201dEgon\u201c\u7684\u624b\u673a\u53f7\n===>\u6b63\u67e5\nres = Author.objects.filter(name="Egon").values_list("author_detail__telephone")\nprint(res) # <QuerySet [(1861131111,)]>\n\n===>\u53cd\u67e5\nres = AuthorDatail.objects.filter(author__name="egon").values("telephone")\nprint(res) # \u540d\u5b57\u7684\u5927\u5c0f\u5199\u4e0d\u91cd\u8981\uff0c\u56e0\u4e3amysql\u4e2d\u7684\u67e5\u8be2\u9ed8\u8ba4\u4e5f\u5ffd\u7565\u5927\u5c0f\u5199\n\n# 2\u3001\u67e5\u8be2\u201dnid=1\u7684\u8be6\u60c5\u4fe1\u606f\u5bf9\u5e94\u7684\u4f5c\u8005\u540d\u5b57\u201c\n===>\u6b63\u67e5\nres = Author.objects.filter(author_detail__nid=1).values_list("name")\nprint(res) # <QuerySet [('EGON',)]>\n\n===>\u53cd\u67e5\nres = AuthorDatail.objects.filter(nid=1).values_list("author__name")\nprint(res) # <QuerySet [('EGON',)]><\/code><\/pre>\n\u591a\u5bf9\u591a\u67e5\u8be2\uff1aapp01_autor,app01_book_autors,app01_book<\/p>\n
# \u6b63\u5411\u6848\u4f8b\uff1a\u67e5\u8be2\u201d\u8ddfegon\u5b66\u7b97\u547d\u201c\u7684\u6240\u6709\u4f5c\u8005\n===>\u6b63\u67e5\nres = Book.objects.filter(name="\u8ddfegon\u5b66\u7b97\u547d").values_list("authors__name")\nprint(res) # <QuerySet [('EGON',), ('Tom',), ('Jack',)]>\n\n===>\u53cd\u67e5\nres = Author.objects.filter(book__name="\u8ddfegon\u5b66\u7b97\u547d").values_list("name")\nprint(res) # <QuerySet [('EGON',), ('Tom',), ('Jack',)]>\n\n# \u67e5\u8be2\u201dEgon\u201c\u90fd\u51fa\u4e86\u54ea\u4e9b\u4e66\n===>\u6b63\u67e5\nres = Author.objects.filter(name="egon").values_list("book__name")\nprint(res) # <QuerySet [('\u8ddfegon\u5b66\u7b97\u547d',), ('\u8ddfegon\u5b66\u98ce\u6c34',)]>\n\n===>\u53cd\u67e5\nres = Book.objects.filter(authors__name="egon").values_list("name")\nprint(res) # <QuerySet [('\u8ddfegon\u5b66\u7b97\u547d',), ('\u8ddfegon\u5b66\u98ce\u6c34',)]><\/code><\/pre>\n\u5982\u679c\u6709\u5fc5\u8981\uff0c\u4f60\u53ef\u4ee5\u4e00\u76f4\u8fde\u7eed\u8de8\u8868<\/p>\n
# 1\u3001\u67e5\u8be2\u201c666\u51fa\u7248\u793e\u201d\u51fa\u7248\u8fc7\u7684\u6240\u6709\u4e66\u7c4d\u53ca\u671f\u4f5c\u8005\u540d\u5b57\n===>\u6b63\u67e5\nres = Book.objects.filter(publish__name="666\u51fa\u7248\u793e").values_list("name","authors__name")\nprint(res)\n\n<QuerySet [('\u8ddfegon\u5b66\u7b97\u547d', 'EGON'), ('\u8ddfegon\u5b66\u7b97\u547d', 'Tom'), ('\u8ddfegon\u5b66\u7b97\u547d', 'Jack'), ('\u8ddfegon\u5b66\u98ce\u6c34', 'EGON'), ('\u8ddfegon\u5b66\u98ce\u6c34', 'Jack')]>\n\n===>\u53cd\u67e5\nres = Publish.objects.filter(name="666\u51fa\u7248\u793e").values_list("book__name","book__authors__name")\nprint(res)\n\n# 2\u30012011\u5e74\u51fa\u751f\u7684\u4f5c\u8005\u51fa\u7248\u8fc7\u7684\u6240\u6709\u4e66\u7c4d\u540d\u79f0\u4ee5\u53ca\u51fa\u7248\u793e\u540d\u79f0\n===>\u6b63\u67e5\nres=Book.objects.filter(authors__author_detail__birthday__year=2011).values_list("name","publish__name")\nprint(res)\n<QuerySet [('\u8ddfegon\u5b66\u7b97\u547d', '666\u51fa\u7248\u793e'), ('\u8ddfegon\u5b66\u98ce\u6c34', '666\u51fa\u7248\u793e')]>\n\n===>\u53cd\u67e5\nres=AuthorDatail.objects.filter(birthday__year="2011").values_list("author__book__name","author__book__publish__name")\nprint(res)<\/code><\/pre>\n\u4e09\u3001\u67e5\u8be2\u76f8\u5173\u53c2\u6570\u8865\u5145<\/h2>\n1\u3001\u591a\u5bf9\u5bf9\u53c2\u6570\uff1asymmetrical<\/h3>\n
\u4ec5\u7528\u4e8e\u591a\u5bf9\u591a\u81ea\u5173\u8054\u65f6\uff0c\u6307\u5b9a\u5185\u90e8\u662f\u5426\u521b\u5efa\u53cd\u5411\u64cd\u4f5c\u7684\u5b57\u6bb5\u3002\u9ed8\u8ba4\u4e3aTrue\u3002<\/p>\n
\u4e3e\u4e2a\u4f8b\u5b50\uff1a<\/p>\n
class Person(models.Model):\n name = models.CharField(max_length=16)\n friends = models.ManyToManyField("self")\n\u6b64\u65f6\uff0cperson\u5bf9\u8c61\u5c31\u6ca1\u6709person_set\u5c5e\u6027\u3002\n\nclass Person(models.Model):\n name = models.CharField(max_length=16)\n friends = models.ManyToManyField("self", symmetrical=False)\n\u6b64\u65f6\uff0cperson\u5bf9\u8c61\u73b0\u5728\u5c31\u53ef\u4ee5\u4f7f\u7528person_set\u5c5e\u6027\u8fdb\u884c\u53cd\u5411\u67e5\u8be2\u3002<\/code><\/pre>\n2\u3001foreign key\u53c2\u6570\uff1arelated_name\u4e0erelated_query_name<\/h3>\n
related_name = "xxx"
\n\u53cd\u5411\uff1a\u5c0f\u5199\u6a21\u578b\u540d_set \u6362\u6210 xxx<\/p>\n
related_query_name = "xxx"
\n\u53cd\u5411\uff1a\u5c0f\u5199\u6a21\u578b\u540d_set \u6362\u6210 xxx_set<\/p>\n
\u4f8b\u5982\uff1a<\/p>\n
class Classes(models.Model):\n name = models.CharField(max_length=32)\n\nclass Student(models.Model):\n name = models.CharField(max_length=32)\n theclass = models.ForeignKey(to="Classes")\n\n\u5f53\u6211\u4eec\u8981\u67e5\u8be2\u67d0\u4e2a\u73ed\u7ea7\u5173\u8054\u7684\u6240\u6709\u5b66\u751f\uff08\u53cd\u5411\u67e5\u8be2\uff09\u65f6\uff0c\u6211\u4eec\u4f1a\u8fd9\u4e48\u5199\uff1a\n\nmodels.Classes.objects.first().student_set.all()\n\u5f53\u6211\u4eec\u5728ForeignKey\u5b57\u6bb5\u4e2d\u6dfb\u52a0\u4e86\u53c2\u6570 related_name \u540e\uff0c\n\nclass Student(models.Model):\n name = models.CharField(max_length=32)\n theclass = models.ForeignKey(to="Classes", related_name="students")\n\u5f53\u6211\u4eec\u8981\u67e5\u8be2\u67d0\u4e2a\u73ed\u7ea7\u5173\u8054\u7684\u6240\u6709\u5b66\u751f\uff08\u53cd\u5411\u67e5\u8be2\uff09\u65f6\uff0c\u6211\u4eec\u4f1a\u8fd9\u4e48\u5199\uff1a\n\nmodels.Classes.objects.first().students.all()<\/code><\/pre>\n\u56db\u3001*\u805a\u5408\u4e0e\u5206\u7ec4\u67e5\u8be2*<\/em><\/strong><\/h2>\n1\u3001annotate<\/h3>\n
\u5206\u7ec4\u67e5\u8be2annotate\u7b49\u540c\u4e8emysql\u7684group by\uff0c\u4f46\u662fannotate\u7684\u5206\u7ec4\u8981\u5206\u4e24\u79cd\u60c5\u51b5\u8ba8\u8bba<\/p>\n
1\u3001\u9ed8\u8ba4\u4ee5\u8868\u7684\u4e3b\u952e\u5b57\u6bb5\u5206\u7ec4<\/p>\n
\u7ba1\u7406\u5668objects\u5de6\u8fb9\u7684\u90a3\u4e2a\u6a21\u578b\u662f\u8c01\u5c31\u4ee5\u8c01\u7684\u4e3b\u952e\u5b57\u6bb5\u4f5c\u4e3a\u5206\u7ec4\u4f9d\u636e\uff0c\u4f8b\u5982Book.objects.annotate()\uff0c\u5219\u6309\u7167Book\u7684\u4e3b\u952e\u5b57\u6bb5\u5206\u7ec4<\/p>\n
\u4e3e\u4f8b<\/p>\n
# 1\u3001\u6bcf\u672c\u4e66\u7684\u4f5c\u8005\u4e2a\u6570\nres=Book.objects.annotate(authors_num=Count('authors')).values("name","authors_num")\nprint(res)\n\n\u539f\u751fsql\u5206\u6790\uff1a\n\u4f1a\u5148\u94fe\u63a5\u8868app01_book\u548capp01_authors\uff0c\u7136\u540e\u518d\u6309\u7167app01_book\u8868\u7684\u4e3b\u952e\u5b57\u6bb5\u5206\u7ec4\uff0c\u6b64\u5904app01_book\u8868\u7684\u4e3b\u952e\u5b57\u6bb5\u4e3anid\n\n# 2\u3001\u6bcf\u4e2a\u51fa\u7248\u793e\u5356\u7684\u6700\u4fbf\u5b9c\u7684\u90a3\u672c\u4e66\u7684\u4ef7\u683c\nres=Publish.objects.annotate(x=Min("book__price")).values("x")\nprint(res) # <QuerySet [{'x': Decimal('2.00')}]>\n\n\u539f\u751fsql\u5206\u6790\uff1a\u540c\u4e0a\n\n# 3\u3001\u7edf\u8ba1\u4e0d\u6b62\u4e00\u4e2a\u4f5c\u8005\u7684\u56fe\u4e66\nres = Book.objects.annotate(n=Count("authors")).filter(n__gt=1).values_list("name", "n")\nprint(res)\n\n# 4\u3001\u67e5\u8be2\u6bcf\u4e2a\u4f5c\u8005\u7684\u4e66\u7684\u603b\u4ef7\u683c\nres=Author.objects.annotate(s=Sum("book__price")).values('s')\nprint(res)\n\n\u539f\u751fsql\u5206\u6790:\n\u4f1a\u5148\u94fe\u63a5\u8868app01_author\u3001app01_book_authors\u3001app01_book\n\u7136\u540e\u518d\u6309\u7167app01_author\u8868\u7684\u4e3b\u952e\u5b57\u6bb5\u5206\u7ec4\uff0c\u6b64\u5904\u4e3aapp01_author.nid<\/code><\/pre>\n2\u3001\u5982\u679c\u60f3\u6309\u7167\u6307\u5b9a\u7684\u5b57\u6bb5\u5206\u7ec4\uff0c\u5219\u9700\u8981\u5f15\u5165values()<\/p>\n
annotate()\u524d\u9762\u7684\u51fa\u73b0\u4e86values()\uff0c\u5c31\u4f1a\u4ee5values()\u4e2d\u6307\u5b9a\u7684\u5b57\u6bb5\u5206\u7ec4
\n\u5982\u679c\u6ca1\u6709\uff0c\u5c31\u4f1a\u9ed8\u8ba4\u6309\u7167\u6a21\u578b\u7684\u4e3b\u952e\u5b57\u6bb5\u5206\u7ec4\uff0c\u4f8b\u5982
\nBook.objects.values("price").annotate() # \u6309\u7167Book\u6a21\u578b\u7684price\u5b57\u6bb5\u5206\u7ec4<\/p>\n
# 1\u3001\u7edf\u8ba1\u6bcf\u5e74\u51fa\u7248\u7684\u4e66\u4e2a\u6570\nres=Book.objects.values("publish_date__year").annotate(n=Count("nid")).values("publish_date__year","n")\nprint(res)\n\n# \u8f93\u51fa\u7ed3\u679c\n<QuerySet [{'publish_date__year': 2021, 'n': 2}, {'publish_date__year': 2022, 'n': 1}]><\/code><\/pre>\n\u5982\u679c\u6211\u4eec\u60f3\u7edf\u8ba1\u54ea\u4e00\u5e74\u54ea\u4e00\u6708\u51fa\u7248\u7684\u4e66\u4e2a\u6570\uff0c\u9700\u8981\u7528\u5230date_format\u51fd\u6570\uff0c\u6b64\u65f6\u5c31\u9700\u8981\u8c03\u7528extra\u6765\u6267\u884cdate_format\u4e86\uff0c\u5982\u4e0b\uff0c\u6ce8\u610f%\u8981\u8fde\u7eed\u5199\u4e24\u4e2a\uff0c\u7b2c\u4e00\u4e2a\u4ee3\u8868\u53d6\u6d88\u7b2c\u4e8c%\u7684\u7279\u6b8a\u610f\u4e49<\/p>\n
res=Book.objects.extra(select={"y_m":"date_format(publish_date,'%%Y-%%m')"}).values("y_m").annotate(n=Count("nid")).values("y_m","n")\n\nprint(res) \n\n# \u8f93\u51fa\u7ed3\u679c\n<QuerySet [{'y_m': '2021-02', 'n': 2}, {'y_m': '2022-02', 'n': 1}]><\/code><\/pre>\nps\uff1a<\/p>\n
\u5728\u4e25\u683c\u6a21\u5f0f\u4e0b\uff08ONLY_FULL_GROUP_BY\uff09\u5206\u7ec4\u4e4b\u540e\u9ed8\u8ba4\u53ea\u80fd\u83b7\u53d6\u5206\u7ec4\u4f9d\u636e\uff0c\u82e5\u67e5\u8be2\u4e86\u975e\u5206\u7ec4\u5b57\u6bb5\uff0c\u4f1a\u5bfc\u81f4\u9519\u8bef\uff0c\u9700\u8981\u4fee\u6539\u6570\u636e\u5e93\u6a21\u5f0f\uff1a\n\n#\u8bbe\u7f6esql_mole\u5982\u4e0b\u64cd\u4f5c(\u6211\u4eec\u53ef\u4ee5\u53bb\u6389ONLY_FULL_GROUP_BY\u6a21\u5f0f)\uff1a\nmysql> set global sql_mode='STRICT_TRANS_TABLES,NO_ZERO_IN_DATE,NO_ZERO_DATE,ERROR_FOR_DIVISION_BY_ZERO,NO_AUTO_CREATE_USER,NO_ENGINE_SUBSTITUTION';<\/code><\/pre>\n\u4e94\u3001F\u67e5\u8be2\u4e0eQ\u67e5\u8be2<\/h2>\n1\u3001 aggregate<\/h3>\n
\u82e5\u60f3\u628a\u6574\u5f20\u8868\u5f53\u6210\u4e00\u4e2a\u7ec4\u6765\u4f7f\u7528\u805a\u5408\u51fd\u6570\uff0c\u5e94\u8be5\u8c03\u7528aggregate<\/p>\n
# 1\u3001\u5148\u5bfc\u5165\u805a\u5408\u51fd\u6570\nfrom django.db.models import Max, Min, Avg, Sum, Count\n"""\n\u5c0f\u7a8d\u95e8\uff1a\n\u53ea\u8981\u662f\u8ddf\u6570\u636e\u5e93\u76f8\u5173\u7684\u6a21\u5757\u57fa\u672c\u90fd\u5728django.db.models\u91cc\u9762\n\u5982\u679c\u6ca1\u6709\u90a3\u4e48\u5e94\u8be5\u5728django.db\u91cc\n"""\n\n# 2\u3001\u67e5\u8be2\u6240\u6709\u4f5c\u8005\u7684\u6700\u5927nid\u3001\u6700\u5c0f\u5e74\u9f84\u3001\u5e73\u5747\u5e74\u9f84\u3001\u5e74\u9f84\u4e4b\u548c\u3001\u4f5c\u8005\u4e2a\u6570\n\nres = Author.objects.aggregate(\n Max("age"),\n Min("age"), \n Avg("age"), \n Sum("age"), \n Count("nid")\n )\n\nprint(res) # \u8c03\u7528\u7684sql\u4e3a\uff1aselect avg("age"),max("nid"),... from app01_author;\n{'age__max': 30, 'age__min': 10, 'age__avg': 20.0, 'age__sum': 60, 'nid__count': 3}\n\n# 3\u3001\u4e5f\u53ef\u4ee5\u6307\u5b9akey\u503c\nres = Author.objects.aggregate(\n x=Max("age"),\n y=Min("age"),\n )\nprint(res) \n{'x': 30, 'y': 10}<\/code><\/pre>\n2\u3001F\u67e5\u8be2<\/h3>\n
F\u67e5\u8be2\u591f\u5e2e\u4f60\u76f4\u63a5\u83b7\u53d6\u5230\u8868\u4e2d\u7684\u67d0\u4e2a\u5b57\u6bb5\u5bf9\u5e94\u7684\u503c\uff0c\u5177\u4f53\u5e94\u7528\u5982\u4e0b<\/p>\n
# \u4fee\u6539\u6a21\u578bBook\u589e\u52a0\u9605\u8bfb\u6570\u4e0e\u8bc4\u8bba\u6570\u5b57\u6bb5\uff0c\u7136\u540e\u91cd\u65b0\u8fc1\u79fb\u6570\u636e\u5e93\uff0c\u65b0\u589e\u597d\u8bb0\u5f55\nclass Book(models.Model):\n nid = models.AutoField(primary_key=True)\n name = models.CharField(max_length=32)\n price = models.DecimalField(max_digits=5, decimal_places=2)\n publish_date = models.DateField(auto_now_add=True)\n # \u9605\u8bfb\u6570\n read_num=models.IntegerField(default=0)\n # \u8bc4\u8bba\u6570\n comment_num=models.IntegerField(default=0)\n\n publish = models.ForeignKey(to='Publish',to_field='nid',on_delete=models.CASCADE)\n authors=models.ManyToManyField(to='Author')\n def __str__(self):\n return self.name\n\nfrom django.db.models import F\n# 1\u3001\u67e5\u8be2\u9605\u8bc4\u8bba\u6570\u5927\u4e8e\u9605\u8bfb\u6570\u7684\u4e66\u7c4d\u540d\nres = Book.objects.filter(comment_num__gt=F("read_num"))\nprint(res)\n\n# 2\u3001\u5c06\u6240\u6709\u4e66\u7684\u4ef7\u683c\u5728\u539f\u6765\u7684\u57fa\u7840\u4e0a\u589e\u52a050\u5143\nBook.objects.update(price=F("price")+50)<\/code><\/pre>\n\u6ce8\u610f\uff0c\u9488\u5bf9\u6570\u5b57\u8fd0\u7b97\uff0cF\u53ef\u4ee5\u76f4\u63a5\u4e0e\u6570\u5b57\u8fdb\u884c\u6570\u5b66\u8fd0\u7b97\uff0c\u4f46\u5982\u679c\u6211\u4eec\u60f3\u62fc\u63a5\u5b57\u7b26\u4e32\uff0c\u5219\u9700\u8981\u5f15\u5165Concat\u5e76\u914d\u5408Value\u4e00\u8d77\u5b9e\u73b0\uff0c\u5982\u4e0b<\/p>\n
# 3\u3001\u5c06\u6240\u6709\u4e66\u7c4d\u7684\u540d\u79f0\u540e\u9762\u52a0\u7206\u6b3e\u4e24\u4e2a\u5b57\nfrom django.db.models.functions import Concat\nfrom django.db.models import Value, F\n\nBook.objects.update(name=Concat(F('name'), Value("\u7206\u6b3e")))\n# Book.objects.update(name=F('name') + "\u7206\u6b3e") # \u9519\u8bef\uff0c\u6240\u6709\u4e66\u7684\u540d\u5b57\u90fd\u4f1a\u88ab\u6539\u4e3a0<\/code><\/pre>\n3\u3001Q\u67e5\u8be2<\/h3>\n
\u5bf9\u4e8efilter()\u65b9\u6cd5\u5185\u9017\u53f7\u5206\u9694\u5f00\u7684\u591a\u4e2a\u6761\u4ef6\uff0c\u90fd\u662fand\u5173\u7cfb\uff0c\u5982\u679c\u60f3\u7528or\u6216\u8005not\u5173\u7cfb\uff0c\u5219\u9700\u8981\u4f7f\u7528Q<\/p>\n
from django.db.models import Q\n\nBook.objects.filter(Q(nid__gte=3), Q(nid__lte=5)) # \u8fd8\u662fand\u5173\u7cfb\nBook.objects.filter(Q(nid__lte=3) | Q(nid__gte=5)) # or\u5173\u7cfb\n\nBook.objects.filter(~Q(nid__gt=2)) # ~ \u7b49\u540c\u4e8e\u5728\u6761\u4ef6\u524d\u52a0\u4e86not \u4ee3\u8868: ! nid>2\u5373nid<=2\nBook.objects.filter(~Q(nid__gt=2) | Q(nid__gte=5)) # \u4ee3\u8868nid<=2 or nid>=5<\/code><\/pre>\nQ\u67e5\u8be2\u7684\u9ad8\u9636\u7528\u6cd5\uff1a\u80fd\u591f\u4ee5\u5b57\u7b26\u4e32\u4f5c\u4e3a\u67e5\u8be2\u5b57\u6bb5<\/p>\n
q = Q()\nq.children.append(('nid__gt', 2)) # \u6761\u4ef6\u4e2d\u5f15\u7528\u7684\u5b57\u6bb5\u4e3a\u5b57\u7b26\u4e32\u7c7b\u578b\nq.children.append(('price__lt', 50))\nres = Book.objects.filter(q) # filter\u5185\u53ef\u4ee5\u76f4\u63a5\u653eq\u5bf9\u8c61\uff0c\u9ed8\u8ba4\u8fd8\u662fand\u5173\u7cfb\nprint(res)\n\nq = Q()\nq.connector = 'or'\nq.children.append(('nid__lte', 2))\nq.children.append(('nid__gte', 5))\nres = Book.objects.filter(q) # \u6b64\u65f6\u662for\u5173\u7cfb\nprint(res)\n\n# \u90a3\u4ec0\u4e48\u573a\u666f\u4e0b\uff0c\u6211\u4eec\u67e5\u8be2\u6761\u4ef6\u4e2d\u7684\u5b57\u6bb5\u662f\u5b57\u7b26\u4e32\u7c7b\u578b\u5462\uff1f\n# \u6bd4\u5982\u6211\u4eec\u5236\u4f5c\u4e00\u4e2a\u641c\u7d22\u529f\u80fd\uff0c\u6211\u4eec\u9700\u8981\u6839\u636e\u7528\u6237\u8f93\u5165\u641c\u7d22\u5b57\u6bb5\u5b8c\u6210\u67e5\u8be2\uff0c\u800c\u7528\u6237\u8f93\u5165\u7684\u90fd\u662f\u5b57\u7b26\u4e32\u7c7b\u578b\uff0c\u6b64\u65f6\u5c31\u7528\u5230\u4e86Q\u7684\u9ad8\u9636\u7528\u6cd5<\/code><\/pre>\n","protected":false},"excerpt":{"rendered":"\u8bb0\u5f55\u64cd\u4f5c\u4e4b\u589e\u5220\u6539\u67e5 \u4e00\u3001\u5355\u8868 1\u3001 \u6dfb\u52a0\u8bb0\u5f55 \u51c6\u5907\u8868 from django.db import models […]<\/p>\n","protected":false},"author":3,"featured_media":6798,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":[],"categories":[3,405],"tags":[],"_links":{"self":[{"href":"https:\/\/egonlin.com\/index.php?rest_route=\/wp\/v2\/posts\/6174"}],"collection":[{"href":"https:\/\/egonlin.com\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/egonlin.com\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/egonlin.com\/index.php?rest_route=\/wp\/v2\/users\/3"}],"replies":[{"embeddable":true,"href":"https:\/\/egonlin.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=6174"}],"version-history":[{"count":0,"href":"https:\/\/egonlin.com\/index.php?rest_route=\/wp\/v2\/posts\/6174\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/egonlin.com\/index.php?rest_route=\/wp\/v2\/media\/6798"}],"wp:attachment":[{"href":"https:\/\/egonlin.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=6174"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/egonlin.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=6174"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/egonlin.com\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=6174"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
![\"\"](\"https:\/\/egonlin.com\/wp-content\/uploads\/2022\/04\/wps18.jpg\")
<\/div><\/p>\n