mongodb query tool

Tags: query statement Use order select ice NTS ring Expression red On the left is the MONGODB query statement, and the right is the SQL statement. Compared with the use, very convenient. Db.users.find () SELECT * from Users Db.users.find ({"age": + }) select * from the users where age = Db.users.find ({"username": "Joe", "age": + }) select * fr

Label:Read some information, corresponding only need to know how to query and use MongoDB for me, these are enough.On the left is the MONGODB query statement, and the right is the SQL statement. Compared with the use, very convenient.Db.users.find () SELECT * from UsersDb.users.find ({"Age": +}) SELECT * from the users

Tags: UI directory lin rdl hat enqueued Tor it comes withThere is a need: tracking MongoDB SQL statements and slow query collection Step one: Use the MongoDB self-function to see how many DML statements have been run over a period of time. Run under the bin directory./mongostat-port Port number you can see the following data Its output has the following columns:

equality of NULL as an element in the array, even if there is only one element in the array. Then there is the $exists determination of whether the specified key exists.> db.test.find({"x": {"$in": [null], "$exists":true}}){ "_id" : ObjectId("4fd59d30b9ac507e96276f1b"), "x" : null } Regular queries The regular syntax for Perl rules is used in MongoDB. Such as:> db.test.find(){ "_id" : ObjectId("4fd59ed7b9ac507e96276f1d"), "name" : "step

Test the effect of the key location on the query in MongoDB: 50 MongoDB development skills: the article "accelerated scanning by establishing hierarchical documents" explains that proper Chromatography can reduce MongoDB's access to fields and increase the speed. I have never thought of such a situation before, but I have never heard of it in relational databases

Entity data in the database, where cus_id, amount I was born into an orderly number, pour the number of records is 200w: Public classtest{/// ///PRIMARY Key ObjectId is the primary key type that the MongoDB comes with/// PublicObjectId Id {Get;Set; } /// ///Customer number/// [Bsonelement ("cust_id")] Public stringCustomerId {Get;Set; } /// ///Total/// [Bsonelement ("Amount")] Public intAmount {Get;Set

The previous article introduced how to conduct distributed storage of Relational Data Based on Mongodb. With storage, queries will be involved. Although it can be queried in a common way, we will introduce how to use the MapReduce function provided in MONGODB for query today.I have written an article about MongoDb MapR

1. Basic query: Constructs query data. Copy Code code as follows: > Db.test.findOne () { "_id": ObjectId ("4fd58ecbb9ac507e96276f1a"), "Name": "Stephen", "Age": 35, "Genda": "Male", "Email": "stephen@hotmail.com" } --Multi-condition query. The following example is equivalent to the WHERE name = "Stephen" and age = 35 of the SQL statement >

command line tool, in fact, is also a JS interpreter, support JS syntax Mongod: The database server, each instance starts a process that can fork to run in the background. Mongodump/mongorestore: Data backup and recovery tools. Mongoexport/mongoimport: Data export and Import tool. MONGOFILE:GRIDFS management tool that enables binary file access. MONGOs

the background so that other database activities are not blocked when the index is built. The default value is False. uniqueA Boolean that creates a unique index. The default value is False. nameA String that specifies the name of the index. If not specified, MongoDB generates an indexed field with the name and sort order concatenation. dropDups, Boolean, when a unique index is created, only the first one is retained if duplicate delet

The official MongoDB documentation shows that the overwrite query is the following query: All query fields are part of the index All the query return fields are in the same index Because all fields that appear in the qu