重新学习mongodb：面向文档的数据

Myth丶恋晨 2022-05-05 16:00 292阅读 0赞

**schema设计(概要，计划，图表)：**

**使用数据库系统建模时，可以先思考以下问题：**

![70][]

**电子商务数据模式：**

商品文档的例子：

doc =
    { _id: new ObjectId("4c4b1476238d3b4dd5003981"),
      slug: "wheel-barrow-9092",
      sku: "9092",
      name: "Extra Large Wheel Barrow",
      description: "Heavy duty wheel barrow...",
    
      details: {
        weight: 47,
        weight_units: "lbs",
        model_num: 4039283402,
        manufacturer: "Acme",
        color: "Green"
      },
    
      total_reviews: 4,
      average_review: 4.5,
    
      pricing:  {
        retail: 589700,
        sale: 489700,
      },
    
      price_history: [
          {retail: 529700,
           sale: 429700,
           start: new Date(2010, 4, 1),
           end: new Date(2010, 4, 8)
          },
    
          {retail:  529700,
           sale:  529700,
           start: new Date(2010, 4, 9),
           end: new Date(2010, 4, 16)
          },
      ],
    
      category_ids: [new ObjectId("6a5b1476238d3b4dd5000048"),
                        new ObjectId("6a5b1476238d3b4dd5000049")],
    
      main_cat_id: new ObjectId("6a5b1476238d3b4dd5000048"),
    
      tags: ["tools", "gardening", "soil"],
    
    }

商品类别：

doc =
    {  _id: ObjectId("6a5b1476238d3b4dd5000048"),
       slug: "gardening-tools",
       ancestors: [{ name: "Home",
                     _id:  ObjectId("8b87fb1476238d3b4dd50003"),
                     slug: "home"
                    },
    
                    { name: "Outdoors",
                      _id:  ObjectId("9a9fb1476238d3b4dd500001"),
                      slug: "outdoors"
                    }
       ],
    
       parent_id: ObjectId("9a9fb1476238d3b4dd500001"),
    
       name: "Gardening Tools",
       description: "Gardening gadgets galore!",
    }

查找商品：

db.products.find(\{category\_ids:ObjectId('6a5b1476238d3b4dd5000048')\});

在商品目录下查询所有的类别，使用$in操作符

products = db.products.findOne({category_ids:ObjectId('6a5b1476238d3b4dd5000048')});
    product = products.category_ids;
    print(product);
    db.categories.find({_id:{$in:product}})

用户和订单

{ _id: ObjectId("4c4b1476238d3b4dd5000001"),
      username: "kbanker",
      email: "kylebanker@gmail.com",
      first_name: "Kyle",
      last_name: "Banker",
      hashed_password: "bd1cfa194c3a603e7186780824b04419",
      addresses:  [
        {name: "home",
         street: "588 5th Street",
         city: "Brooklyn",
         state: "NY",
         zip: 11215},
    
        {name: "work",
         street: "1 E. 23rd Street",
         city: "New York",
         state: "NY",
         zip: 10010}
      ],
      payment_methods:  [
        {name: "VISA",
         last_four: 2127,
         crypted_number: "43f6ba1dfda6b8106dc7",
         expiration_date: new Date(2014, 4)
        }
      ]
    }

评价

doc =
    { _id: new ObjectId("4c4b1476238d3b4dd5000041"),
      product_id: new ObjectId("4c4b1476238d3b4dd5003981"),
      date: new Date(2010, 5, 7),
      title: "Amazing",
      text: "Has a squeaky wheel, but still a darn good wheel barrow.",
      rating: 4,
    
      user_id: new ObjectId("4c4b1476238d3b4dd5000041"),
      username: "dgreenthumb",
    
    
      helpful_votes: 3,
      voter_ids: [ new ObjectId("4c4b1476238d3b4dd5000041"),
                      new ObjectId("7a4f0376238d3b4dd5000003"),
                      new ObjectId("92c21476238d3b4dd5000032")
      ]
    }

**数据库、集合和文档：**

数据库：数据库是集合和索引的命名空间和物理组合。

管理数据可：mingodb没有显示的创建数据库的方式。

删除集合中所有的数据：prooduct.find(\{\}).delete\_many

删除集合：product.drop

删除数据库：db.dropDatabase()

数据库文件的分配：

![70 1][]

集合：是结构或者概念相似的文档容器。

管理集合：创建集合是隐身的。只有插入文档是才创建。

db.createCollection('users')

db.createCollection("users",\{size:20000\})

集合重命名：

db.products.renameCollection("store\_product");

盖子集合：

db.createCollection("users.action",\{capped:true,size:16384,max:100\})

盖子集合不容许删除单个文档，也不能增加文档的大小。

TTL集合

![70 2][]

![70 3][]

[70]: /images/20220505/09f67fcd1bca4e2296bb298e77f284bc.png
[70 1]: /images/20220505/ebb4efcf7e814fc98dcc3dc184bfba54.png
[70 2]: /images/20220505/b44f7068e01641998ae5912afdd1944d.png
[70 3]: /images/20220505/0318121085c14c378b87d70ecb77260e.png