Windows MONGODB Basic Gameplay series two curd operations (create, update, read and delete)

Windows MongoDB Basic Gameplay series

• Introduction and installation of the Windows MongoDB Basic gameplay series
• Windows MONGODB Basic Gameplay series two curd operations (create, update, read and delete)

Simply say a few words in MongoDB 3 elements: db (Database), collection (collection), document (documentation)
Where collection is similar to a table in a database, document is similar to a row, so that we can compare the contents of memory learning. Data format MongoDB documents is a binary form of the Bson format (a kind of JSON in the storage format)
Insert Operation-c① Single insertion

Db.testData.insert ({"Name": "A", "Age": 18})

② BULK INSERT (directly is a JS loop, so it seems to be not very cool, will JS should be able to play a very good turn to MongoDB look, it seems I have to work a bit)

for (var i = n; I < i++) {
Db.testData.insert ({"Name": String.fromCharCode (i+47), "Age": i})
}

Update operation-u① Overall updates (replaces the entire document with values other than _id, with a completely new document as the second parameter of the update)

Db.testData.update ({"Name": "K"},{"name": "K", "Age": 28})

② Partial update (update a specific field in a document, here's just a look at the $inc/$set)

• $inc can increase or decrease the value of one of the document's numeric values.

• Db.testData.update ({"Name": "K"},{$inc: {"Age": 72}})

• $set Update the value of a field in a document, or the value of an embedded document in a document

• Db.testData.update ({"Name": "K"},{$set: {"Age": 28}})

③upsert (By default, update () does nothing if it does not match to the document, but if it is upsert (that is, when the third parameter of update is true), when no match is made to the document, the contents of the second parameter are inserted as a new document)

Db.testData.update ({"Name": "L"},{"name": "L", "age": 29},true)

④ batch update (this is also the problem that we often meet, but can think of the solution or circular change, supposedly this efficiency is relatively low, such as the subsequent documentation update this related method, hope to see this problem after a good solution friends left a little comment, Thank you) The Find Operation-rmongodb provides the Db.collection.find () method for querying operations, simply by selecting document in collection. That is, we usually do the same thing in a table.
① $gt, $gte, $lt, $lte, $ne, no special (>,>=,<,<=,!=,=)

Demo:db.testData.find ({"Age": {$gt: $}}) Db.testData.find ({"Age": {$gte: $}}) Db.testData.find ({"Age": {$lt: 20}}) Db.testData.find ({"Age": {$lte: $}}) Db.testData.find ({"Age": {$ne: $}}) Db.testData.find ({"Age": 20})

② $and, $or, $in, $nin (And,or,in,not in)

Demo:db.testData.find ({$and: [{"Name": "A", "Age":]}) Db.testData.find ({$or: [{"Name": "A", "name": "B"}]}) Db.testData.find ({"name": {$in: ["A", "B"]}}) Db.testData.find ({"name": {$nin: ["A", "B"]}})

Remove operation-D in MongoDB, Db.collection.remove () is the removal of a document from a collection. Delete all Documents

Db.testData.remove ({})

The above method simply removes all the documents from the collection, the collection itself is still present, and if you want to delete the collection directly, you can delete the eligible document by dropping () using a more effective method.

Db.testData.remove ({"Name": "A"})

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Windows MONGODB Basic Gameplay series two curd operations (create, update, read and delete)