創(chuàng)建集合

db.createCollection("demo")

固定集合

固定集合無法使用remove，只能使用drop刪除集合
固定集合進(jìn)行插入速度極快
按照插入順序的查詢輸出速度極快
能夠在插入最新數(shù)據(jù)時,淘汰最早的數(shù)據(jù)

db.createCollection("capped_demo", {"capped": true, "size": 10000, max: 10})

固定集合參數(shù)

capped：設(shè)置為true
size：文檔字節(jié)大小
max：制定文檔個數(shù)，超出后最后插入的文檔替換最早的文檔

添加數(shù)據(jù)

db.capped_demo.insert({
    "uid" : 1,
    "ip" : "127.0.0.1",
    "time" : new Date()
})

將集合轉(zhuǎn)換為固定集合

db.runCommand({"convertToCapped": "demo", size: 10000})

判斷是否是固定集合

db.capped_demo.isCapped()

添加文檔測試

db.capped_demo.insert({
    "uid" : 1,
    "ip" : "127.0.0.1",
    "time" : new Date()
})
db.capped_demo.insert({
    "uid" : 2,
    "ip" : "127.0.0.1",
    "time" : new Date()
})
db.capped_demo.insert({
    "uid" : 3,
    "ip" : "127.0.0.1",
    "time" : new Date()
})
db.capped_demo.insert({
    "uid" : 4,
    "ip" : "127.0.0.1",
    "time" : new Date()
})
db.capped_demo.insert({
    "uid" : 5,
    "ip" : "127.0.0.1",
    "time" : new Date()
})
db.capped_demo.insert({
    "uid" : 6,
    "ip" : "127.0.0.1",
    "time" : new Date()
})
db.capped_demo.insert({
    "uid" : 7,
    "ip" : "127.0.0.1",
    "time" : new Date()
})
db.capped_demo.insert({
    "uid" : 8,
    "ip" : "127.0.0.1",
    "time" : new Date()
})
db.capped_demo.insert({
    "uid" : 9,
    "ip" : "127.0.0.1",
    "time" : new Date()
})
db.capped_demo.insert({
    "uid" : 10,
    "ip" : "127.0.0.1",
    "time" : new Date()
})
db.capped_demo.insert({
    "uid" : 11,
    "ip" : "127.0.0.1",
    "time" : new Date()
})