CURD操作

mongodb的一些概念：

  • A record in MongoDB is a document, which is a data structure composed of field and value pairs, similar to JSON objects. The value of a field can include other documents, arrays, and arrays of documents. A document is roughly equivalent to a row in a relational database table.
  • A collection in MongoDB is a group of documents, and is roughly equivalent to a relational database table.
  • A database in MongoDB is a group of collections, and is similar to a relational database with a group of related tables.

查询数据库列表：

show dbs

返回结果为空，因为目前还没有创建任何数据库。使用use命令创建数据库，例如创建catalog数据库：

use catalog

当创建新数据库时，里面没有创建collection，可以使用如下命令确认：

show collections

可以使用createCollection命令创建collection。

创建Documents

以下命令将在catalog数据库中创建新的collection(products)，并插入一条document：

db.products.insert({
"name" : "RayBan Sunglass Pro",
"sku" : "1590234",
"description" : "RayBan Sunglasses for professional sports people",
"inventory" : 100
})

DocumentDB返回成功插入document的数量：

image-20211128113037974

insertMany命令可以一次插入多个document：

db.products.insertMany([
{
"name" : "GUCCI Handbag",
"sku" : "3451290",
"description" : "Fashion Hand bags for all ages",
"inventory" : 75
},
{
"name" : "Round hat",
"sku" : "8976045",
"inventory" : 200
},
{
"name" : "Polo shirt",
"sku" : "6497023",
"description" : "Cool shirts for hot summer",
"inventory" : 25
},
{
"name" : "Swim shorts",
"sku" : "8245352",
"description" : "Designer swim shorts for athletes",
"inventory" : 200
},
{
"name" : "Running shoes",
"sku" : "3243662",
"description" : "Shoes for work out and trekking",
"inventory" : 20
}
])

返回插入的ObjectId。注意这个ObjectId是DocumentDB自动生成的，在query操作时会返回不同的值。

image-20211128113309069

Documents - 读操作

可以使用以下命令来读取插入到DocumentDB中的数据，find命令中指定了过滤的条件，pretty命令用于优化结果的展示（如果不加会把结果放到一行显示）。

db.products.find({"sku":"1590234"}).pretty()

返回以下结果：

Amazon DocumentDB CRUD 3

使用find命令时，如果不加查询的条件，会返回前20条document。

rs0:PRIMARY> db.products.find().pretty()
{
        "_id" : ObjectId("61a2f7cc5e0271eedc932907"),
        "name" : "RayBan Sunglass Pro",
        "sku" : "1590234",
        "description" : "RayBan Sunglasses for professional sports people",
        "inventory" : 100
}
{
        "_id" : ObjectId("61a2f8635e0271eedc932908"),
        "name" : "GUCCI Handbag",
        "sku" : "3451290",
        "description" : "Fashion Hand bags for all ages",
        "inventory" : 75
}
{
        "_id" : ObjectId("61a2f8635e0271eedc932909"),
        "name" : "Round hat",
        "sku" : "8976045",
        "inventory" : 200
}
{
        "_id" : ObjectId("61a2f8635e0271eedc93290a"),
        "name" : "Polo shirt",
        "sku" : "6497023",
        "description" : "Cool shirts for hot summer",
        "inventory" : 25
}
{
        "_id" : ObjectId("61a2f8635e0271eedc93290b"),
        "name" : "Swim shorts",
        "sku" : "8245352",
        "description" : "Designer swim shorts for athletes",
        "inventory" : 200
}
{
        "_id" : ObjectId("61a2f8635e0271eedc93290c"),
        "name" : "Running shoes",
        "sku" : "3243662",
        "description" : "Shoes for work out and trekking",
        "inventory" : 20
}

Documents - 更新操作

使用$set操作符，在之前的document中新增一个reviews字段，它是一个数组结构，包括review和rating两个属性：

db.products.update(
{"sku":"1590234"},
{
$set: {	
"reviews" : [{
"rating" :4,
"review":"perfect glasses"
},{
"rating" :4.5,
"review":"my prized possession"
},{
"rating" :5,
"review":"Just love it"
}]}
}
)

返回matched, upserted, modified的document数量：

image-20211128114243574

可以再读取这条document，确认更改生效：

db.products.find({"sku":"1590234"}).pretty()

Amazon DocumentDB CRUD 5

Documents - 删除操作

使用remove命令删除document：

db.products.remove({"sku":"8976045"})

返回被删除的document数量：

image-20211128114509153