MongoDB 筆記 (一) : insert

識搵野唔識入野都無用, MongoDB 入野, 有幾個方法:

• db.collection.insert()
• db.collection.insertOne()
• db.collection.insertMany()

db.collection.insert

db.collection.insert(
   <document or array of documents>,
   {
     writeConcern: <document>,
     ordered: <boolean>
   }
)

可以用黎加一份 document (可以睇成係一隻 JSON record), 或者成個 array 既 documents

例如:

• db.sample.insert({user:"Super169"})
• db.sample.insert([{user:"Super167"},{user:"Super168"},{user:"Super169"}])

writeConcern 比較複雜, 我自己都唔係好明, 有興趣自己睇喇, 平時我都唔用(應該係唔識用).

db.collection.insertOne

db.collection.insertOne(
   <document>,
   {
      writeConcern: <document>
   }
)

唔駛多講, 只可以 insert 一份 document, 唔可以成個 array 比佢.

例如:

• db.sample.insertOne({user:"Super169"})

db.collection.insertMany

db.collection.insertMany(
   [ <document 1> , <document 2>, ... ],
   {
      writeConcern: <document>,
      ordered: <boolean>
   }
)

同 insertOne 對著幹, 只可以成個 array 比佢, 唔可以單獨一份 document.

不過, 個 array 入面可以只係得一份 document....甚至無野.

例如:

• db.sample.insertMany([{user:"Super167"},{user:"Super168"},{user:"Super169"}])

insert, insertOne 同 insertMany 有乜分別?

無事無幹, 對個 collection 而言, 係無分別既, 你可以用哂 insert 唔駛煩.

不過, 佢地既 return object 就有 D 唔同, 你要做 error handling, 就要識分.

例如:

• db.sample.insert({user:"Super169"})

WriteResult({ "nInserted" : 1 })

• db.sample.insertOne({user:"Super169"}) 

{        "acknowledged" : true,        "insertedId" : ObjectId("5901a950276033a2cfe79009")}

• db.sample.insert([{user:"Super167"},{user:"Super168"},{user:"Super169"}])

BulkWriteResult({
        "writeErrors" : [ ],
        "writeConcernErrors" : [ ],
        "nInserted" : 3,
        "nUpserted" : 0,
        "nMatched" : 0,
        "nModified" : 0,
        "nRemoved" : 0,
        "upserted" : [ ]
})

• db.sample.insertMany([{user:"Super167"},{user:"Super168"},{user:"Super169"}])

{
        "acknowledged" : true,
        "insertedIds" : [
                ObjectId("5901a9e9276033a2cfe7900d"),
                ObjectId("5901a9e9276033a2cfe7900e"),
                ObjectId("5901a9e9276033a2cfe7900f")
        ]
}

至於用邊個, 睇下你自己想點了.  insert 完想攞番個 key 去再做野, 就用 insertOne 或者 insertMany, 否則, insert 完知道得唔得就夠, 用 insert 就可以了.