MongoDB

    This note aims to learn and summarize MongoDB for the HTTPS://WWW.SHIYANLOU.COM/COURSES/RUNNING/50 website. 1, Start MongoDBbecause the MongoDB service does not start up with the system, you need to start the MongoDB service first:

Summarize the next few days MongoDB study notes /** * Get mongoclient * @author xuyw * @email [email protected] * @param Ho St * @param port * @return */ Public StaticMongoclientgetmongoclient(String host,int... port) {Mongoclient mongoclient

User table nameTo select or create a database, if the database is empty, then MongoDB will continue to observe whether the database has actions written by the action, if any, create the databaseShow DBSShow databases equivalent to MySQL, used to

First, download the MongoDB packageWebsite: http://www.mongodb.org/downloads2. InstallationDownload good if the MSI package is installed directly into a place, if it is a folder then put it directly to a place.First through the CMD into the MongoDB

Database-relational algebra and relational operations OverviewTraditional set operations (sum, difference, intersection, Cartesian Product)Dedicated relational operationsUnion) R and S have the same object n (that is, there are n attributes in both

C ++ Implementation of Tree B # Include # Include # Include Using namespace std; class BTree {static const int M = 2; struct BTNode {int keyNum; int key [2 * M-1]; // keyword array struct BTNode * child [2 * M]; // child node

MHA clears relaylog (purge_relay_logs) By default, the slave database's relay logs in the MySQL database will be automatically deleted after the SQL thread is executed. However, in the MHA scenario, the recovery of some lagging slave databases

AerospikeC client manual --- error handlingFor error handling, each database operation accepts an as_error object as a parameter. When an error occurs during the operation, the as_error parameter is filled in with the status code and error message.

AerospikeC client manual --- Big Data TypeBig Data Type overview big data type (LDT) is a complex object that resides on the Aerospike server and maintained by applications through UDF. The data associated with LDT is not transmitted to the client

AerospikeC client manual --- logThe log Aerospike C client has a Log facility used to record internal log information. By default, the logger writes the log information to stderr. However, the application can change the log details or provide a

Redis Message Queue Redis message queue is easy to use and has no configuration. It is much lighter than ActiveMQ and has simple functions. If you only need simple subscription and release, you can consider using it. Subscription operation The

MongDB start WARNING: softrlimitstoolow # MongoMongoDB shell version: 3.0.2Connecting to: testServer has startup warnings:T12: 34: 19.688-0700 I CONTROL [initandlisten]T12: 34: 19.688-0700 I CONTROL [initandlisten] ** WARNING: soft rlimits too low.

Storage and processing of dates and timesThis section summarizes the knowledge about date and time that are frequently used in databases.Because the character set has an effect on the date and time, this is the first thing we need to pay attention

Database-physical OptimizationPhysical Optimization Algebraic optimization changes the order and combination of operations in a query statement, and does not involve the underlying access path.There are many access solutions for a query statement,

Database-Physical DesignPhysical Design of databases The storage structure and access method of a database on physical devices are called the physical structure of a database. It depends on the selected database management system.The process of

Ubuntu14.04 install and configure jdk7 1. Download: Go to http://www.oracle.com/technetwork/java/javase/downloads/jdk7-downloads-1880260.html to download the JDK. I am going to dk-7u55-linux-x64.tar.gz.Default placed

Redis learning-master-slave copyFeatures of Redis master-slave copy The same Master can have multiple Slaves. The server Load balancer under the Master node can also accept connections and synchronization requests from other Server Load balancer

Text Files of diverse data sources Diverse data sources are becoming more and more common in report development. the effective support of the collection and computing reports for diverse data sources makes the development of such reports very simple,

Mysql network disconnection and reconnection Recently, I was working on a project's background daemon program. I needed multiple threads to operate mysql database services. To enhance the robustness of daemon, I unplugged the network cable after

[Data Center reconstruction]-view, trigger, and use of stored procedures In the data room charging system, it is very troublesome to write multiple SQL statements to query multiple tables. To facilitate code writing, code decoupling and, we