MongoDB database update and deletion documentation

MongoDB database update and deletion documentation
Create a collection createCollection ()

<Span style = "font-size: 14px;"> name: the name of the created set. options: an initialized document (optional) </span>

<Span style = "font-size: 14px;"> db. createCollection ("jingdong") # No parameter {"OK": 1}> show collectionsjingdongsystem. indexes> db. createCollection ("jingdong", {capped: 1, autoIndexID: 1, size: 6142800, max: 10000}) # With parameter {"OK": 1} </span>

Capped: the type is Boolean. If it is true, a set of fixed sizes is created. When the number of entries reaches the maximum, the previous entries are automatically overwritten. Specify the parameter size when setting it to true;
AutoIndexID: Boolean type. The default value is false. If it is set to true, an index is automatically created on _ id field. s;
Size: If capped is true, specify the maximum value of the parameter, in bytes;
Max: specifies the maximum number of documents. You do not need to create a collection in mogodb, because the collection is automatically created when you create a document.

Delete COLLECTION db. COLLECTION. drop ()

<span style="font-size:14px;">> use JDswitched to db JD> show collectionsjingdongjingdong1system.indexes> db.jingdong.drop()ture> show collectionsjingdong1system.indexes</span>

Insert document db. COLLECTION_NAME.insert (document)

</Pre> <pre name = "code" class = "python"> <span style = "font-size: 14px;"> userdoc1 = ({"user_id ": 1, "name": "cloud", "state": "active", "actor": "user", "e-mail": "test@qq.com", "VM_num ": 2, "time": [{"date": "2014-08-12", "hour": "10:53 PM"}]})> userdoc2 = ({"user_id": 2, "name": "testadmin", "state": "active", "actor": "admin", "e-mail": "test@qq.com", "VM_num": 2, "time": [{"date": "2014-08-11", "hour": "06:34 AM"}]})> doc = ({"name": "peter ", "position": "teacher"}) # first define the document> use JDswitched to db JD> db. jingdong. insert (userdoc1) WriteResult ({"nInserted": 1})> db. jingdong. insert (userdoc2) WriteResult ({"nInserted": 1})> db. jingdong. insert (doc1) WriteResult ({"nInserted": 1}) </span>

Update document db. COLLECTION_NAME.update (SELECTION_CRITERIA, UPDATED_DATA)

<Span style = "font-size: 14px;"> # change the e-mail of user_id = 2 to group@qq.com> db. jingdong. update ({"user_id": "02", "e-mail": "test@qq.com" },{ $ set: {"e-mail": "group@qq.com "}}) # The content of the first braces indicates the search condition, and the content of the second braces indicates the updated data WriteResult ({"nMatched": 1, "nUpserted": 1, "nModified ": 1})> db. jingdong. find () </span>

<Pre name = "code" class = "python"> <span style = "font-size: 14px;"> the default update function updates only one document, if you want to use all documents, you need to add multi: ture </span>

<span style="font-size:14px;">db.shiyanlou.update({"e-mail":"test@qq.com"},{$set:{"e-mail":"group@qq.com"}},{multi:ture})</span>

Replace the existing document db. COLLECTION_NAME.save ({_ id: ObjectId (), NEW_DATA })

<span style="font-size:14px;">> db.shiyanlou.save({"_id":ObjectId("53ea174ccb4c62646d9544f4","name":"Bob","position":"techer")})WriteResult({"nMatched":1,"nUpserted":1,"nModified":1})</span>

Delete document db. COLLECTION_NAME.remove (DELECTION_CRITERIA)

<span style="font-size:14px;">> db.shiyanlou.remove({"name":"Bob"})WriteResult({"nRemoved":1})</span>

Then you can use find () to view all documents and verify that the deletion is successful.

CreateCollection (): Creates a collection.

Db. COLLECTION. drop (): deletes a set.

Db. COLLECTION_NAME.insert (document): Insert document

Db. COLLECTION_NAME.update (SELECTION_CRITERIA, UPDATED_DATA): update document

Db. COLLECTION_NAME.save ({_ id: ObjectId (), NEW_DATA}): replace an existing document

Db. COLLECTION_NAME.remove (DELECTION_CRITERIA): delete a document