most popular nosql database

satisfy a+b=10, otherwise the transaction fails. 3, I (isolation) Independence The so-called independence refers to the concurrent transactions do not affect each other, if one transaction to access the data is being modified by another transaction, as long as another transaction is not committed, the data it accesses is not affected by uncommitted transactions. For example, now there is a transaction from a account transfer 100 to B account, in the case of this transaction is not c

Label:"How to explain why the database is difficult to expand", the problem comes from Quora, the owner added that he has some basic knowledge of the database, but still do not understand why the expansion of the database is so difficult. Bole Online compiled excerpts of this question and answer post two popular replie

In the previous article, "from architectural features to functional defects, re-understanding of the analytical distributed database", we completed the different "distributed database" of the horizontal analysis, this article Ivan will talk about the second part of the disassembly, combined with the difference between NoSQL and Newsql, from the portrait of the OL

Label:four categories of NoSQL databaseskey value (key-value) store databaseThis type of database primarily uses a hash table that has a specific key and a pointer to the specific data. The advantage of the Key/value model for IT systems is simplicity and ease of deployment. But if the DBA only queries or updates part of the value, Key/value becomes inefficient. Examples include: Tokyo cabinet/tyrant, Redis

NoSQL database What is a NoSQL database?Non-relational database is NoSQL, relational database represents MySQL;relational database, it is ne

A detailed description of the branch product of DBosql Database Introductionis a non-relational database service, it can solve the common database concurrency, such as traditional database IO and performance bottlenecks, as well as a relational database is a supplement, has

Tags: style blog http using OS dataContent directory: Why use a NoSQL database? Key-Value Database Document Database Column Family Database Graph database Attached Mind Map Reference

Transferred from: http://www.oschina.net/question/258230_134502In general, there are two kinds of database things: Reading things (select), modifying Things (Update,insert). When there is no isolation control, multiple things at the same time on the same (the operation of the data may affect the results of the final expected, there are usually four cases(1) Two updates when you modify a piece of data at the same time, it is obvious that this situation

a few popular database systems The most "easy" database system-microsoft SQL Server If you are going to be a DBA, it is recommended that you choose a database system that is now more popular. This means that you will have more opportunities for employment, communication a

Brief introductionMean is a full stack development framework for JavaScript. More aboutThe storage of persistent data with MongoDB is a part of mean web full stack development.MongoDB is a product between a relational database and a non-relational database, and is the most versatile and most like relational database in a non-relational

Tags: ble format info Sch form comparison des object strNow the three more popular database query table records are as follows:Mysql:Use INFORMATION_SCHEMA;Select Table_name,table_rows from tables where Table_schema = ' db instance ' order by table_rows Desc;SQL Server 2008:SELECT DISTINCT object_name (ID) as table name, rows as table record number from sysindexes order by using row number desc;Oracle:Selec

Label:Scylla 1.2.4 was released.SCYLLADB is a Cassandra that is rewritten in C + +, processing 1 million TPS per node per second. The SCYLLADB is fully compatible with Apache Cassandra and has a throughput of 10x times more than Cassandra, reducing latency. Qkxue.net Experience Summary:SCYLLADB claims to be the world's fastest NoSQL columnstore database. No official update notes.： Source Code (Zip)

If you are going to be a DBA, it is recommended that you choose a database system that is now more popular. This means that you will have more opportunities for employment, communication and training, and that there are popular reasons why you can worry a lot. Of course, the employment competition pressure is also relatively big. The average beginner chooses Micr

Introduction MySQL is one of the most popular free open source programs in history. It is the backbone of the database for tens of thousands of websites, and it can be a powerful proof of the exponential growth of the Internet over the past 10 years (and linux®). So, if MySQL is really that important, why is there more and more high-end derivatives of the core MySQL products? This is because MySQL is a fre

　　1 Introduction to several database development tools 1.1 VB Visual Basic is a visual programming tool that uses the basic language as its basic language. I have seen it in China and even the world. It was the most popular programming tool in China, and it still occupies a very important position, everyone has a certain understanding of its quality. VB, as an early development program, is easy to learn and

Tags: repeatable log strong row data serial BLE failure ref=========================================== original link: Popular understanding of database isolation mechanism reproduced please specify the source! =========================================== In understanding the database isolation mechanism, found that many articles on the web are stereotyped, expla

Tags: nosql database redis ubuntu nosql concurrencyI. Introduction to REDIS:NOSQL and no only SQL, is high concurrency, large data exists, different from relational database. Owned: Non-relational, distributed, open source, can be horizontally expanded.Redis is a key-value storage system. Similar to memcached, it suppo

[Java] several popular database SQL Paging 1. Oracle: Select * from (select row _. *, rownum _ from (query_ SQL) Row _ Where rownum = 2. SQL Server: Select top @ pagesize * From tablename where id not in (select top @ pagesize * (@ page-1) ID from tablename order by ID) order by ID 3. MySQL Select * From tablename limit position, counter 4. DB2 Select * from (select *, rownumber () as row_ne

Tags: customers ast conversions stringstr Reverse order nosql database flush variable type 1, set a 1 assignment is converted to a character type by default (type a can query the variable type) 2, get a query A's value 3, Rpush list_a a b c defines a list containing a,b,c three variables list_a 4, Lpus H List_a A inserts element a 5, lrange list_a 0 9 to the left of the list list_a the first 10 elem

Today's web sites are becoming more and more flexible with data storage requirements, where NoSQL is becoming more prevalent in non-relational databases. The so-called non-relational database refers to a database that does not use the SQL language for data manipulation. Such a database does not have a fixed pattern for