mongodb 3 6

. The second type: Db.users.find ({"Age": {"$gte": +, "$lte": 30}}) This is a multivalued query that finds documents that match multiple values, and MongoDB uses the first key in the index "age" to get a matching document. If you use "username" to make a query, the index does not work. The third type: Db.users.find ({"Age": {"$gte": +, "$lte": +}}). Sort ({"username": 1}) This is also a multivalued query, similar to the previous one, but this time the

starts, it will not stop until the difference of data blocks between any two nodes does not exceed 2. 5. Chip key (1) The partition key is a column of the set. This column must exist for each record. Otherwise, a record that does not have a partition key column cannot be allocated. (2) The partition key can be a single column or multiple columns. (3) data distribution is based on the scope of the chip key. If a timestamp column is used as the partiti

--logpath=/data/shard/log/s0.log--directory Perdb>mongod--shardsvr--port 20001--dbpath=/data/shared/s1--fork--logpath=/data/shard/log/s1.log--directory Perdb STEP2 : Start the config server instance >mongod--configsvr--port 30000--dbpath=/data/shared/config--fork--logpath=/data/shard/log/config.log-- Directoryperdb STEP3 : Start the route server instance >mongos--port 40000--configdb localhost:30000--fork--logpath=/data/shared/log/route

transfer charges, based on Azure standard network rates: Storage cost is relatively simple, according to their own data volume to estimate, then the RU cost how to calculate?AzureA single request unit is defined inRUused to represent reads (by self-linking orID) A containingTenunique attribute value (except for System properties).1 KBthe processing capacity required for the item. and1Kthe data is written to5aRU, a calculationRUThe examples are as follows: And for users to more easily calcu

Turn on slow query profilingProfiling level Description0: Close, do not collect any data. 1: Collect slow query data, default is 100 milliseconds. 2: Collect all data1. Open profiling by modifying the configuration fileTo modify the startup mongo.conf, insert the following code# turn on slow query, 200 ms record profile = 1= 2002, after the start of MongoDB service, through the Mongoshell to carry out temporary open, as long as the

Not in the official MongoDB documentation, but is actually feasible and requires the following steps 1. Install key Apt-key adv--keyserver hkp://keyserver.ubuntu.com:80--recv 7F0CEB10 2. Add a source echo "Deb Http://repo.mongodb.org/apt/debian wheezy/mongodb-org/3.0 main" | sudo tee/etc/apt/sources.list.d/mongodb-org-3.0.list

Tags: mongodbNot in the official MongoDB documentation, but is actually feasible and requires the following steps1. Install keyApt-key adv--keyserver hkp://keyserver.ubuntu.com:80--recv 7F0CEB102. Add a sourceecho "Deb Http://repo.mongodb.org/apt/debian wheezy/mongodb-org/3.0 main" | sudo tee/etc/apt/sources.list.d/mongodb-org-3.0.list3. Update the sourceApt-get

Tags: mongodbAdd user error on MongoDB as follows:> Db.adduser (' User01 ', ' 123456 '); 2016-07-29t14:50:28.932+0800 E QUERY typeerror:property ' addUser ' of object admin is not a function at (shell) : 1:4After the investigation, the reason is that in MongoDB version 3 has been deprecated adduser, changed to CreateUser.[[emailprotected]bin]$./mongo127.0.0.1:270

nonexistent fields, reduce occupancy, increase speed! Introduce a thing first { field: { $exists: } } True to find M data FALSE to find data without M You cannot find a record on a sparse index that does not exist on this field, forcing the specified index. Hint (index name) Forces the specified index to be empty after the search results. 4. Location Index Category: 1.2D index filed by points on a plane 2.2Dsphere index filed by point on spherical surface Method: 1. Find points within

1. UpdateDb.persons.update ({name: "Caohui"},{id:2}); update only one, replace update directlyDb.persons.update ({name: "Caohui"},{id:2},true), update only one, replace update directly, insert if not present2. Full-scale updateDb.persons.update ({name: "Caohui"},{$set: {id:2}},false,true); full-scale local update3. $set {$set: {Field:value}}It is used to specify a key value pair, if there is a key value is modified, does not exist to add4. $inc {$inc: {Field:value}}Only used with numeric types,

the UserID query in the Doctor table to the corresponding entry and pass the information into the req.body.doctorObject. As you can guess, this code is reusable. Of course, this code reuse situation will be more limited, because it is rough, on this point, the following will give a more comprehensive code of reuse. To run the command line in the project folder, run the command: Node Server.js If there are no errors, the following prompt is available: The hint content is defined in Server.js.

collection, using the $inc to add 1 to the age of name User1 in the collection, the other keys are the same, $inc means that a key value is added minus the specified value4. Update the document in the collection, $set the value used to specify a key, and if the key does not exist, create it.For example:To add an address to the document name User1, you can use the command:Db.c1.update ({name: "user1"},{$set: {address: "BJ"}},0,1)The document named User1 is modified to address TJ, the other key-v