ORM基本操作

阿新 • • 發佈：2020-11-24

1、建立單表模型類

class Goods(models.Model):
    goods_name = models.CharField(max_length=32)
    goods_price = models.DecimalField(max_digits=9,decimal_places=2)
    goods_num = models.IntegerField()

    class Meta:
        db_table = 'tb_goods'

2、ＯＲＭ基本操作

   class ORMView(APIView):
    def get(self,request):
        # 單一查詢，如果結果不存在報錯
        goodsobj = Goods.objects.get(goods_price=6.66)
        obj = GoodsSerializers(goodsobj)
        return Response(obj.data)
   
   # # 查詢不包含id=3的資料
    # goodsobj = Goods.objects.exclude(id=3)
    # obj = GoodsSerializers(goodsobj, many=True)
    # return Response(obj.data)
        # # 查詢結果的數量
# goodsobj = Goods.objects.all().count()
# return Response(goodsobj)

 # #   聚合函式　　使用aggregate()過濾器呼叫聚合函式。聚合函式包括：Avg 平均，Count 數量，Max 最大，Min 最小，Sum 求和
     # goodsobj = Goods.objects.aggregate(Sum('goods_num'))
    # print(goodsobj)
    # # obj = GoodsSerializers(goodsobj, many=True)
    # return Response({'data':''})
  # #   比較查詢　　欄位名__lt：小於    欄位名__lte：小於等於
    # goodsobj = Goods.objects.filter(id__lt=4)
    # obj = GoodsSerializers(goodsobj, many=True)
    # return Response(obj.data)
 # #   比較查詢　　欄位名__gt：大於    欄位名__gte：大於等於
    # goodsobj = Goods.objects.filter(id__gte=2)
    # obj = GoodsSerializers(goodsobj, many=True)
    # return Response(obj.data)

  # #  　空查詢　　欄位名__isnull
# goodsobj = Goods.objects.filter(goods_name__isnull=False)
# obj = GoodsSerializers(goodsobj, many=True)
# return Response(obj.data)

 # #   模糊查詢　欄位名__endswith　以　莓　結尾的資料
    # goodsobj = Goods.objects.filter(goods_name__endswith='莓')
    # obj = GoodsSerializers(goodsobj, many=True)
    # return Response(obj.data)
      # #   模糊查詢　欄位名__tartswith　以　蘋　開頭的資料    # goodsobj = Goods.objects.filter(goods_name__startswith='蘋')    # obj = GoodsSerializers(goodsobj,many=True)    # return Response(obj.data)    # #   模糊查詢　欄位名__contains　包含　果　的的資料    # goodsobj = Goods.objects.filter(goods_name__contains='果')    # obj = GoodsSerializers(goodsobj,many=True)    # return Response(obj.data)

  # # 範圍查詢:  in  只查詢列表中的具體值
    # goodsobj = Goods.objects.filter(goods_price__in=[12,25,6.66]).all()
    # obj = GoodsSerializers(goodsobj,many=True)
    # return Response(obj.data)

    # # 範圍查詢:  range １～２０之間
    # goodsobj = Goods.objects.filter(goods_price__range=[1,20]).all()
    # obj = GoodsSerializers(goodsobj,many=True)
    # return Response(obj.data)

  #    排序查詢：  order_by 降序只需在欄位名前加上 “ - ”
        goodsobj = Goods.objects.all().order_by('-goods_num')
        obj = GoodsSerializers(goodsobj, many=True)
        return Response(obj.data)

        #    F方法：比較兩個欄位物件之間的關係用F物件，F方法可以進行簡單運算　
        #    查詢價格　大於等於　庫存的物件
        goodsobj = Goods.objects.filter(goods_price__gte=F('goods_num'))
        obj = GoodsSerializers(goodsobj, many=True)
        return Response(obj.data)
        
        #    Q方法：對物件進行復雜查詢，並支援&（and）,|（or），~（not）操作符
        #    查詢價格大於等於15的資料　或庫存大於等於10的資料
        goodsobj = Goods.objects.filter(Q(goods_price__gte=15) | Q(goods_num__gte=10))
        obj = GoodsSerializers(goodsobj, many=True)
        return Response(obj.data)

3、建立一對多、多對多模型類

# 電影
class Movie(models.Model):
    movie_name = models.CharField(max_length=32)
    class Meta:
        db_table = 'tb_movie'


# 角色
class Role(models.Model):
    role_name = models.CharField(max_length=32)
    role_price = models.DecimalField(max_digits=9, decimal_places=2)
    role_desc = models.CharField(max_length=32)

    class Meta:
        db_table = 'tb_role'


# 演員
class Actor(models.Model):
    name = models.CharField(max_length=32)
    address = models.CharField(max_length=32, null=True, blank=True)
    age = models.IntegerField(null=True,blank=True)
    phone = models.CharField(max_length=32, null=True, blank=True)
    movie = models.ForeignKey(Movie, on_delete=models.CASCADE)
    role = models.ManyToManyField(Role)

    class Meta:
        db_table = 'tb_actor'

一對多正、反查詢

   # #   正向查詢　　物件．模型名．欄位
    # actorobj = Actor.objects.get(id=1)
    # movieo = actorobj.movie.movie_name
    # print(movieo)
    # return Response('ok')

    #   反向查詢  物件．模型名_set
    # movieobj = Movie.objects.get(id=1)
    # actorobj = movieobj.actor_set.all()
    # obj = ActorSerializers(actorobj,many=True)
    # print(obj.data)
    # return Response(obj.data)

4、多對多表操作

class ORMview2(APIView):
    def post(self,request):
        # # 多對多新增
        # # 方法一：在建立manytomany的models裡新增資料，（一條，一個物件）
        # actor = Actor.objects.get(id=5)
        # role = Role.objects.get(id=5)
        #
        # data = actor.role.add(role)
        # print(data)
        # return Response('ok')


# 方法二：在未建立manytomany的models裡新增資料，（一條，一個物件）
    actor = Actor.objects.filter(name='張譯')
    role = Role.objects.get(id=5)

    data = role.actor_set.add(*actor)
    print(data)
    return Response('ok2')

5、父子元件的呼叫

import匯入子元件
components註冊子元件
註冊的子元件當作標籤來使用

子元件

<template>  <div>      <p>今天心情真美麗</p>   </div></template>

父元件

<template>
<div>
 <zi></zi>     <!-- 子元件當標籤使用-->

 </div>

</template>

<script>

import zi from "./zi";     //匯入子元件

export default {

 data() {
   return { 

    };

   },
//註冊子元件
   components: {     

    zi

   },

}
</script>

父元件給子元件傳參

父元件裡的子標籤裡寫上要傳遞的資料（:子元件的引數名字=父元件的引數名字）
在子元件裡註冊引數（props）
使用父元件傳過來的引數

<template>
  <div>
    <zi :str='str'></zi><br>      
    <br>
    <button @click="change_zi()">修改子元件</button>
  </div>
</template>

<script>
import zi from "./zi";
export default {
  data() {
    return {
        str:'',
     
    };
  },

  components: {
    zi
  },

  methods:{
      change_zi(){
          this.str='今天的你真可愛！'
      },
  }
};
</script>

//子元件獲取
<template>
  <div>
      <p>今天心情真美麗</p>
      {{str}}
  </div>
</template>

<script>
export default {
    props:['str'],
    data(){
        return{

        }

    },
  }
</script>

子元件給父元件傳參

子元件裡先用特定的方法來把這個資料傳遞給父元件（this.$emit(‘方法的名字’,要傳遞的資料)）
父元件的子標籤裡來接收資料(@子元件的方法=父元件的方法)
methods裡接收傳過來的val並賦值

<template>
  <div>
      <p>今天心情真美麗</p>
      <button @click="change">修改父元件</button>
  </div>
</template>

<script>
export default {
    data(){
        return{

        }

    },
    methods:{
        change(){
            this.$emit('change_fu','真好！nice!')
        }
        
    }

}
</script>


//父元件獲取
<template>
  <div>
    <zi @change_fu=get_zi></zi><br>
    {{data}}
  </div>
</template>

<script>
import zi from "./zi";
export default {
  data() {
    return {
        data:''
    };
  },

  components: {
    zi
  },

  methods:{
      get_zi(val){
          this.data=val
      }
  }
};
</script>