数据库会用到创建(create)读取(find)更新(update)删除(remove),MongoDB也同样会用到;
一、创建
创建数据库blog,将文档增加到集合post中(先将文档放入post的变量中)
> post={"title":"My blog post","context":"Here's my blog post","date":new Date()} > use blog switched to db blog > db.post.insert(post); WriteResult({ "nInserted" : 1 })
二、读取
> db.post.find() { "_id" : ObjectId("54a50253e287e09898eab58b"), "title" : "My blog post", "context" : "Here's my blog post", "date" : ISODate("2015-01-01T08:15:14.121Z") } > db.post.findOne() { "_id" : ObjectId("54a50253e287e09898eab58b"), "title" : "My blog post", "context" : "Here's my blog post", "date" : ISODate("2015-01-01T08:15:14.121Z") } >
三、更新
重新给变量post赋值
> use blog switched to db blog > post=db.post.findOne() { "_id" : ObjectId("54a50253e287e09898eab58b"), "title" : "My blog post", "context" : "Here's my blog post", "date" : ISODate("2015-01-01T08:15:14.121Z") }
> post.comments = [] [ ]
update方法更新集合
> db.post.update({"title":"My blog post"},post) ;WriteResult({ "nMatched" : 1, "nUpserted" : 0, "nModified" : 1 }) > db.post.findOne() { "_id" : ObjectId("54a50253e287e09898eab58b"), "title" : "My blog post", "context" : "Here's my blog post", "date" : ISODate("2015-01-01T08:15:14.121Z"), "comments" : [ ] }
四、删除
> db.post.remove({"title":"My blog post"}); WriteResult({ "nRemoved" : 1 }) > db.post.findOne(); null >
删除后post集合为空;
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