MongoDB基礎知識
一.文件
文件是MongoDB的核心概念。文件就是鍵值對的一個有序集。注意：鍵是唯一的
如下：
{
"title":"test1",
"content":"There is study",
"date": new Date()
}
二.集合
一組文件，相當與一張表，是動態模式
三.資料庫
多個集合可以組成資料庫
四.MongoDB shell簡介
MongoDB 自帶JavaScript shell，可在shell中使用命令列與MongoDB例項互動
shell中的基本操作
a.建立
insert
> post = {
... "title":"test1",
... "content":"There is study",
... "date": new Date()
... }
{
"title" : "test1",
"content" : "There is study",
"date" : ISODate("2020-07-28T05:49:53.951Z")
}
> db.blog.insert(post)
WriteResult({ "nInserted" : 1 })
b.讀取
find
> db.blog.find()
{ "_id" : ObjectId("5f1f8fc39da18cf3e2cf8071"), "title" : "test1", "content" : "There is study", "date" : ISODate("2020-07-28T02:38:59.968Z"), "width" : 3 }
{ "_id" : ObjectId("5f1fb9909da18cf3e2cf8072"), "title" : "test2", "content" : "There is study", "date" : ISODate("2020-07-28T05:37:20.426Z") }
{ "_id" : ObjectId("5f1fba699da18cf3e2cf8073"), "title" : "test3", "content" : "There is study", "date" : ISODate("2020-07-28T05:40:57.366Z"), "study" : [ "english", "chinese" ] }
{ "_id" : ObjectId("5f1fbaf49da18cf3e2cf8074"), "title" : "test4", "content" : "There is study", "date" : ISODate("2020-07-28T05:43:16.673Z"), "study" : [ "english", "chinese" ], "lickly" : { "food" : "mifan", "ball" : "football" } }
{ "_id" : ObjectId("5f1fbca0837f599809534b75"), "title" : "test1", "content" : "There is study", "date" : ISODate("2020-07-28T05:49:53.951Z") }
findOne
> db.blog.findOne()
{
"_id" : ObjectId("5f1f8fc39da18cf3e2cf8071"),
"title" : "test1",
"content" : "There is study",
"date" : ISODate("2020-07-28T02:38:59.968Z"),
"width" : 3
}
c.更新
update,至少有兩個引數：第一個是限定條件（用於匹配待更新的文件），第二個是新的文件
> post.conments = []
[ ]
> db.blog.update({"title":"test1"},post)
WriteResult({ "nMatched" : 1, "nUpserted" : 0, "nModified" : 1 })
> db.blog.find({"title":"test1"})
{ "_id" : ObjectId("5f1f8fc39da18cf3e2cf8071"), "title" : "test1", "content" : "There is study", "date" : ISODate("2020-07-28T05:49:53.951Z"), "conments" : [ ] }
d.刪除
remove
> db.blog.remove({"title":"test1"})
五.資料型別
1.基本資料型別
.null
null用於表示空值或者不存在的欄位
"conmments" : null
.布林型
ture、false
.數值
"width" : 12.4
height:NumberInt(3)
.字串
"title" : "test1"
.日期
"date" : new Date()
.正則表示式
{"title":/test/}
.陣列
"study" : [ "english", "chinese" ]
.內嵌文件
"lickly" : { "food" : "mifan", "ball" : "football" }
.物件id
"_id" : ObjectId("5f1fb9909da18cf3e2cf8072")