MongoDB学习笔记之文档

#向集合中插入文档有两种方式(insert、save)

db.col.insert({title: 'MongoDB 教程', 
    description: 'MongoDB 是一个 Nosql 数据库',
    by: '菜鸟教程',
    url: 'http://www.runoob.com',
    tags: ['mongodb', 'database', 'NoSQL'],
    likes: 100
});

# 也可以把文档赋值给变量
document=({title: 'MongoDB 教程', 
    description: 'MongoDB 是一个 Nosql 数据库',
    by: '菜鸟教程',
    url: 'http://www.runoob.com',
    tags: ['mongodb', 'database', 'NoSQL'],
    likes: 100
});

db.col.insert(document)

　

#查询集合中的文档，通过find
db.col.find();
{ "_id" : ObjectId("5d020b62f99940c1effaa307"), "title" : "MongoDB 教程", "description" : "MongoDB 是一个 Nosql 数据库", "by" : "菜鸟教程", "url" : "http://www.runoob.com", "tags" : [ "mongodb", "database", "NoSQL" ], "likes" : 100 }
{ "_id" : ObjectId("5d020b80f99940c1effaa308"), "title" : "MongoDB 教程", "description" : "MongoDB 是一个 Nosql 数据库", "by" : "菜鸟教程", "url" : "http://www.runoob.com", "tags" : [ "mongodb", "database", "NoSQL" ], "likes" : 100 }
{ "_id" : ObjectId("5d020b81f99940c1effaa309"), "title" : "MongoDB 教程", "description" : "MongoDB 是一个 Nosql 数据库", "by" : "菜鸟教程", "url" : "http://www.runoob.com", "tags" : [ "mongodb", "database", "NoSQL" ], "likes" : 100 }
{ "_id" : ObjectId("5d020b82f99940c1effaa30a"), "title" : "MongoDB 教程", "description" : "MongoDB 是一个 Nosql 数据库", "by" : "菜鸟教程", "url" : "http://www.runoob.com", "tags" : [ "mongodb", "database", "NoSQL" ], "likes" : 100 }
{ "_id" : ObjectId("5d020b83f99940c1effaa30b"), "title" : "MongoDB 教程", "description" : "MongoDB 是一个 Nosql 数据库", "by" : "菜鸟教程", "url" : "http://www.runoob.com", "tags" : [ "mongodb", "database", "NoSQL" ], "likes" : 100 }
{ "_id" : ObjectId("5d020b84f99940c1effaa30c"), "title" : "MongoDB 教程", "description" : "MongoDB 是一个 Nosql 数据库", "by" : "菜鸟教程", "url" : "http://www.runoob.com", "tags" : [ "mongodb", "database", "NoSQL" ], "likes" : 100 }
{ "_id" : ObjectId("5d020b84f99940c1effaa30d"), "title" : "MongoDB 教程", "description" : "MongoDB 是一个 Nosql 数据库", "by" : "菜鸟教程", "url" : "http://www.runoob.com", "tags" : [ "mongodb", "database", "NoSQL" ], "likes" : 100 }
{ "_id" : ObjectId("5d020b85f99940c1effaa30e"), "title" : "MongoDB 教程", "description" : "MongoDB 是一个 Nosql 数据库", "by" : "菜鸟教程", "url" : "http://www.runoob.com", "tags" : [ "mongodb", "database", "NoSQL" ], "likes" : 100 }

比较insert和save的区别：

其实insert和save在不指定_id的时候效果是一样的,如果指定了_id字段,那么save就是更新当前文档信息

{ "_id" : ObjectId("5d020beff99940c1effaa316"), "title" : "MongoDB 教程", "description" : "MongoDB 是一个 Nosql 数据库", "by" : "菜鸟教程", "url" : "http://www.runoob.com", "tags" : [ "mongodb", "database", "NoSQL" ], "likes" : 100 }

#利用save方法指定_id
db.col.save({
        "_id":"5d020beff99940c1effaa316",
        "title" : "java 教程",
        "description" : "java是一个跨平台的编程语言",
        "by" : "菜鸟教程",
        "url" : "http://www.runoob.com",
        "tags" : [
                "java8",
                "注解",
                "反射",
                "网络编程",
                "epoll 事件驱动",
                "多路复用",
                "声明式API"
        ],
        "likes" : 100
});

#结果如下
{ "_id" : "5d020beff99940c1effaa316", "title" : "java 教程", "description" : "java是一个跨平台的编程语言", "by" : " 菜鸟教程", "url" : "http://www.runoob.com", "tags" : [ "java8", "注解", "反射", "网络编程", "epoll 事件驱动", "多路 复用", "声明式API" ], "likes" : 100 }