From 2f83a3bd30e878a20985dd1b877e3f1e87fb8f01 Mon Sep 17 00:00:00 2001 From: roger Date: Mon, 10 Jul 2023 17:20:28 +0800 Subject: [PATCH] =?UTF-8?q?=E6=A8=A1=E5=9E=8B=E8=BF=99=E5=9D=97=E8=BF=98?= =?UTF-8?q?=E5=B7=AE=E4=B8=8D=E5=B0=91=E5=91=A2?= MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit --- orm_demo/orm_crud.py | 187 +++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 187 insertions(+) diff --git a/orm_demo/orm_crud.py b/orm_demo/orm_crud.py index 1ecbe1d..b8813cb 100644 --- a/orm_demo/orm_crud.py +++ b/orm_demo/orm_crud.py @@ -1,4 +1,6 @@ from orm_demo.models import * +from django.db.models import F, Q, Count +from django.db import connection # 插入数据 # 先实例化对象，然后为对象赋值 @@ -126,11 +128,196 @@ for user in skill_py.user.all(): user_del = UserExtendInfo.objects.get(id=5) skill_del = SkillInfo.objects.get(id=7) result = skill_del.user.remove(user_del) +print(result) # 通过id指定删除哪个用户 skill_del = SkillInfo.objects.get(id=1) result = skill_del.user.remove(2) +print(result) # 清除全部 skill_del = SkillInfo.objects.get(id=8) result = skill_del.user.clear() +print(result) + +# ForeignKey 直接获取关联表数据, 只能用在一对多设置外键的情况 +card_data = CardInfo.objects.select_related('user') +for card in card_data: + print(card.user) + +# ManyToMany 多对多直接获取关联表数据 +skill_data = SkillInfo.objects.prefetch_related('user') +for skill in skill_data: + print(skill.skill_name) + users = skill.user.all() + for user in users: + print(user.true_name) + +# F()函数 +users = UserExtendInfo.objects.all() +for user in users: + user.salary = F('salary') + 1000 + user.save() +for user in users: + user.refresh_from_db() + print(user.salary) + +# Q()函数 用于多条件查询 +user = UserExtendInfo.objects.filter(Q(age__gt=30) & Q(salary__gt=10000)).first() +print(user.username) + +# 执行原生SQL +users = UserExtendInfo.objects.raw("SELECT * FROM orm_user_base_info") +for user in users: + print(type(user), user.username) + +sql = "SELECT * FROM orm_user_extend_info WHERE age > %s and salary > %s" +users = UserExtendInfo.objects.raw(sql, [30, 10000]) +for user in users: + print(type(user), user.username) + +# connect 游标 +# 插入数据 +import django.utils.timezone as timezone + +time_now = timezone.now() +cursor = connection.cursor() +sql = "INSERT INTO orm_skill_info (skill_name, createDate) VALUES (%s, %s)" +cursor.execute(sql, ('selenium', time_now)) +cursor.close() + +# 查询数据 +sql = "SELECT * FROM orm_user_extend_info" +cursor = connection.cursor() +cursor.execute(sql) +row = cursor.fetchone() +print(row) +cursor.close() + +# 更新数据 +cursor = connection.cursor() +try: + update_sql = "UPDATE orm_depart_info SET depart_name = %s WHERE id = %s" + data = ('开发部', 1) + cursor.execute(update_sql, data) + rowcount = cursor.rowcount + print(rowcount) + connection.commit() +except Exception as e: + print(e) + connection.rollback() +finally: + cursor.close() + +# 事务处理 transaction +from django.db import transaction + + +# 方式1：修饰器 + +@transaction.atomic +def trans(request): + save_id = transaction.savepoint() # 开启事件 + try: + # somecode + transaction.savepoint_commit(save_id) # 提交事件 + except Exception as e: + print(e) + transaction.savepoint_rollback(save_id) # 回滚事件 + + +# 方式2： with语句 + +def trans_with(request): + with transaction.atomic(): + save_id = transaction.savepoint() # 开启事件 + try: + # some code + transaction.commit(save_id) # 提交事件 + except Exception as e: + print(e) + transaction.rollback(save_id) # 回滚事件 + + +# 基本查询 +# get 当查询结果多余一条时报错 +user = BaseUserInfo.objects.get(id=2) +print(user) + +# exclude 排除查询出来的数据 +users = UserExtendInfo.objects.exclude(age__lt=30) +for user in users: + print(user.true_name) + +# filter 过滤数据 +users = UserExtendInfo.objects.filter(Q(age__gte=30) & Q(department__in=['开发部', '测试部'])) +for user in users: + print(user.true_name) + +# __gt __gte __lt __lte __in __contains __year __month __day +users = BaseUserInfo.objects.filter(username__contains="孙") +for user in users: + print(user) + +users = BaseUserInfo.objects.filter(create_date__year='2023') +for user in users: + print(user.create_date) + +users = BaseUserInfo.objects.filter(create_date__day='08') +for user in users: + print(user.create_date) + +# values 用于指定显示具体字段 +users = UserExtendInfo.objects.filter(username='张三').values('username', 'true_name', 'salary') +for user in users: + print(user) + print(user['true_name']) + +# distinct 去重 +departs = UserExtendInfo.objects.distinct().values('department') +for d in departs: + print(d) + +# 链式过滤器 +users = UserExtendInfo.objects.filter(age__range=[20, 30]).exclude(salary__lt=17000) +for user in users: + print(user.username) + +# 结果切片 +skills = SkillInfo.objects.all()[1:3] +print(skills) + +# 排序 order_by +user_salary = UserExtendInfo.objects.order_by('salary').all() +for user in user_salary: + print(user.salary) + +# 排序 desc +user_salary = UserExtendInfo.objects.order_by(F('salary').desc()) +for user in user_salary: + print(user.salary) + +# 排序 asc +user_salary = UserExtendInfo.objects.order_by(F('salary').asc()) +for user in user_salary: + print(user.salary) + +# group_by query形式 +users = UserExtendInfo.objects.all() +users.query.group_by = ['department'] +for user in users: + print(user.username, user.department) + +# group_by aggregated count +users = UserExtendInfo.objects.values('username').aaggregate(count=Count('department')) +print(users) + +# count + + +# sum + +# UNION + + +# JOIN