Mongo Shell提供了交互式的MongoDB操作體驗檬贰，通過Mongo Shell我們可以方便地進行查詢驗證及學(xué)習(xí)。本篇我們將通過Mongo Shell來進行MongoDB基本操作介紹。
文檔插入
db.inventory.insertOne(
{ item: "canvas", qty: 100, tags: ["cotton"], size: { h: 28, w: 35.5, uom: "cm" } }
) // 單條插入
db.inventory.insertMany([
{ item: "journal", qty: 25, tags: ["blank", "red"], size: { h: 14, w: 21, uom: "cm" } },
{ item: "mat", qty: 85, tags: ["gray"], size: { h: 27.9, w: 35.5, uom: "cm" } },
{ item: "mousepad", qty: 25, tags: ["gel", "blue"], size: { h: 19, w: 22.85, uom: "cm" } }
]) //多條插入
文檔查詢 - 基礎(chǔ)
初始化查詢記錄
db.inventory.insertMany([
{ item: "journal", qty: 25, size: { h: 14, w: 21, uom: "cm" }, status: "A" },
{ item: "notebook", qty: 50, size: { h: 8.5, w: 11, uom: "in" }, status: "A" },
{ item: "paper", qty: 100, size: { h: 8.5, w: 11, uom: "in" }, status: "D" },
{ item: "planner", qty: 75, size: { h: 22.85, w: 30, uom: "cm" }, status: "D" },
{ item: "postcard", qty: 45, size: { h: 10, w: 15.25, uom: "cm" }, status: "A" }
]);
查詢語句
db.inventory.find( {} ) //所有記錄
db.inventory.find( { status: "D" } ) //status是“D”的記錄
db.inventory.find( { status: { $in: [ "A", "D" ] } } ) //status是“A”或“D”的記錄
db.inventory.find( { status: "A", qty: { $lt: 30 } } ) //status是“A”并且qty小于30的記錄
db.inventory.find( { $or: [ { status: "A" }, { qty: { $lt: 30 } } ] } ) //status是“A”或者qty小于30的記錄
db.inventory.find( {
status: "A",
$or: [ { qty: { $lt: 30 } }, { item: /^p/ } ]
} ) //status是“A”匙监，并且qty小于30或item以p開頭
db.inventory.find( { "size.h": { $lt: 15 }, "size.uom": "in", status: "D" } ) //size.h小于15晦溪，size.uom是“in”并且status是“D”
文檔查詢 - 數(shù)組
初始化查詢記錄
db.inventory.insertMany([
{ item: "journal", qty: 25, tags: ["blank", "red"], dim_cm: [ 14, 21 ] },
{ item: "notebook", qty: 50, tags: ["red", "blank"], dim_cm: [ 14, 21 ] },
{ item: "paper", qty: 100, tags: ["red", "blank", "plain"], dim_cm: [ 14, 21 ] },
{ item: "planner", qty: 75, tags: ["blank", "red"], dim_cm: [ 22.85, 30 ] },
{ item: "postcard", qty: 45, tags: ["blue"], dim_cm: [ 10, 15.25 ] }
]);
查詢語句
db.inventory.find( { tags: ["red", "blank"] } ) //tags數(shù)組為 ["red", "blank"] 的記錄
db.inventory.find( { tags: { $all: ["red", "blank"] } } ) //tags數(shù)組包含“red”和“blank”的記錄
db.inventory.find( { tags: "red" } ) //tags包含“red”的記錄
db.inventory.find( { dim_cm: { $gt: 25 } } ) //dim_cm包含大于25的元素的記錄
db.inventory.find( { dim_cm: { $gt: 15, $lt: 20 } } ) //dim_cm包含大于15的元素，并且包含小于20的元素的記錄
db.inventory.find( { dim_cm: { $elemMatch: { $gt: 22, $lt: 30 } } } ) //dim_cm包含大于22同時小于30的元素的記錄
db.inventory.find( { "dim_cm.1": { $gt: 25 } } ) //dim_cm第二個元素大于25的記錄
db.inventory.find( { "tags": { $size: 3 } } ) //tags有三個元素的記錄
文檔查詢 - 文檔元素數(shù)組
初始化查詢記錄
db.inventory.insertMany( [
{ item: "journal", instock: [ { warehouse: "A", qty: 5 }, { warehouse: "C", qty: 15 } ] },
{ item: "notebook", instock: [ { warehouse: "C", qty: 5 } ] },
{ item: "paper", instock: [ { warehouse: "A", qty: 60 }, { warehouse: "B", qty: 15 } ] },
{ item: "planner", instock: [ { warehouse: "A", qty: 40 }, { warehouse: "B", qty: 5 } ] },
{ item: "postcard", instock: [ { warehouse: "B", qty: 15 }, { warehouse: "C", qty: 35 } ] }
]);
查詢語句
db.inventory.find( { "instock": { warehouse: "A", qty: 5 } } ) //instock中包含元素為 { warehouse: "A", qty: 5 }并且順序相同的記錄
db.inventory.find( { "instock": { qty: 5, warehouse: "A" } } ) //順序不相同魔熏，不能查詢到記錄！Ｌ渲埂道逗！
db.inventory.find( { 'instock.qty': { $lte: 20 } } ) //instock中存在一個元素的qty屬性小于等于20的記錄
db.inventory.find( { 'instock.0.qty': { $lte: 20 } } ) //instock中第一個元素的qty屬性小于等于20的記錄
db.inventory.find( { "instock": { $elemMatch: { qty: 5, warehouse: "A" } } } ) //instock存在一個元素包含屬性qty、warehouse献烦，qty等于5并且warehouse是“A”的記錄
db.inventory.find( { "instock": { $elemMatch: { qty: { $gt: 10, $lte: 20 } } } } ) //instock存在一個元素包含qty滓窍，qty大于10并且小于等于20
db.inventory.find( { "instock.qty": { $gt: 10, $lte: 20 } } ) //instock中任意一個元素的qty屬性大于10并且任意一個元素的屬性小于等于20
db.inventory.find( { "instock.qty": 5, "instock.warehouse": "A" } ) //instock中存在元素的qty屬性等于5并且instock中存在元素的屬性warehouse為‘A’
文檔查詢 - 投影
初始化查詢記錄
db.inventory.insertMany( [
{ item: "journal", status: "A", size: { h: 14, w: 21, uom: "cm" }, instock: [ { warehouse: "A", qty: 5 } ] },
{ item: "notebook", status: "A", size: { h: 8.5, w: 11, uom: "in" }, instock: [ { warehouse: "C", qty: 5 } ] },
{ item: "paper", status: "D", size: { h: 8.5, w: 11, uom: "in" }, instock: [ { warehouse: "A", qty: 60 } ] },
{ item: "planner", status: "D", size: { h: 22.85, w: 30, uom: "cm" }, instock: [ { warehouse: "A", qty: 40 } ] },
{ item: "postcard", status: "A", size: { h: 10, w: 15.25, uom: "cm" }, instock: [ { warehouse: "B", qty: 15 }, { warehouse: "C", qty: 35 } ] }
]);
查詢語句
db.inventory.find( { status: "A" }, { item: 1, status: 1 } ) //status是“A”的記錄，返回字段_id巩那、item吏夯、status
db.inventory.find( { status: "A" }, { item: 1, status: 1, _id: 0 } ) //status是“A”的記錄，返回字段item即横、status
db.inventory.find( { status: "A" }, { status: 0, instock: 0 } ) //status是“A”的記錄噪生，返回status、instock以外的所有字段
db.inventory.find(
{ status: "A" },
{ item: 1, status: 1, "size.uom": 1 }
) //status是“A”的紀錄东囚，返回字段_id跺嗽、item、status页藻、uom(size下面的屬性)
db.inventory.find(
{ status: "A" },
{ "size.uom": 0 }
) //status是“A”的記錄桨嫁，返回uom(size下面的屬性)以外的所有字段
db.inventory.find( { status: "A" }, { item: 1, status: 1, "instock.qty": 1 } ) //status是“A”的紀錄，返回字段_id份帐、item璃吧、status、qty(instock數(shù)組下面的元素的屬性)
db.inventory.find( { status: "A" }, { item: 1, status: 1, instock: { $slice: -1 } } ) //status是“A”的紀錄废境，返回字段_id畜挨、item筒繁、status、instock數(shù)組下最后一條記錄巴元。數(shù)組投影只能使用$elemMatch毡咏、$slice、$务冕。
文檔查詢 - 空值
初始化查詢記錄
db.inventory.insertMany([
{ _id: 1, item: null },
{ _id: 2 }
])
查詢語句
db.inventory.find( { item: null } ) //查詢item為null或item不存在的記錄
db.inventory.find( { item : { $type: 10 } } ) //查詢item為BSON null的記錄
db.inventory.find( { item : { $exists: false } } ) //查詢item不存在的記錄
文檔更新
初始化查詢記錄
db.inventory.insertMany( [
{ item: "canvas", qty: 100, size: { h: 28, w: 35.5, uom: "cm" }, status: "A" },
{ item: "journal", qty: 25, size: { h: 14, w: 21, uom: "cm" }, status: "A" },
{ item: "mat", qty: 85, size: { h: 27.9, w: 35.5, uom: "cm" }, status: "A" },
{ item: "mousepad", qty: 25, size: { h: 19, w: 22.85, uom: "cm" }, status: "P" },
{ item: "notebook", qty: 50, size: { h: 8.5, w: 11, uom: "in" }, status: "P" },
{ item: "paper", qty: 100, size: { h: 8.5, w: 11, uom: "in" }, status: "D" },
{ item: "planner", qty: 75, size: { h: 22.85, w: 30, uom: "cm" }, status: "D" },
{ item: "postcard", qty: 45, size: { h: 10, w: 15.25, uom: "cm" }, status: "A" },
{ item: "sketchbook", qty: 80, size: { h: 14, w: 21, uom: "cm" }, status: "A" },
{ item: "sketch pad", qty: 95, size: { h: 22.85, w: 30.5, uom: "cm" }, status: "A" }
] );
更新語句
db.inventory.updateOne(
{ item: "paper" },
{
$set: { "size.uom": "cm", status: "P" },
$currentDate: { lastModified: true }
}
) //更新item為“paper”的單條記錄血当，$set更新對應(yīng)字段值，$currentDate用于更新lastModified字段（不存在則創(chuàng)建）
db.inventory.updateMany(
{ "qty": { $lt: 50 } },
{
$set: { "size.uom": "in", status: "P" },
$currentDate: { lastModified: true }
}
) //3.2開始支持禀忆，更新qty小于50的多條記錄臊旭，$set更新對應(yīng)字段值，$currentDate用于更新lastModified字段（不存在則創(chuàng)建）
db.inventory.replaceOne(
{ item: "paper" },
{ item: "paper", instock: [ { warehouse: "A", qty: 60 }, { warehouse: "B", qty: 40 } ] }
) //用第二個文檔對象替換item是“paper”的對象
文檔刪除
初始化查詢記錄
db.inventory.insertMany( [
{ item: "journal", qty: 25, size: { h: 14, w: 21, uom: "cm" }, status: "A" },
{ item: "notebook", qty: 50, size: { h: 8.5, w: 11, uom: "in" }, status: "P" },
{ item: "paper", qty: 100, size: { h: 8.5, w: 11, uom: "in" }, status: "D" },
{ item: "planner", qty: 75, size: { h: 22.85, w: 30, uom: "cm" }, status: "D" },
{ item: "postcard", qty: 45, size: { h: 10, w: 15.25, uom: "cm" }, status: "A" },
] );
刪除語句
db.inventory.deleteMany({}) //刪除所有記錄
db.inventory.deleteMany({ status : "A" }) //刪除status是“A”的多條記錄
db.inventory.deleteOne( { status: "D" } ) //刪除status是“D”的第一條記錄
聚合 - 管道
管道方式聚合時箩退，多個聚合運算分布于管道上离熏。每一步聚合運算完成后將結(jié)果交給下一步的聚合運算繼續(xù)處理，以此類推戴涝。聚合運算的基本過程如下圖所示滋戳。
聚合運算示意
通過以上操作，我們看到可以通過Mongo Shell方便地對MongoDB進行日常維護操作啥刻。MongoDB的查詢主要通過查詢方法加上查詢文檔體來實現(xiàn)奸鸯，這對于理解MongoDB第三方客戶端的使用具有重要的指導(dǎo)意義。
