MySQL Database < a >

Introduction to Databases

I am not a technical manual, not for preaching, just a little bit of personal opinion, idle to chat.

Do know, the Web server parallel plus 10 units is very easy, but the database parallel plus 10 is difficult, even if added to, the data is difficult to handle; storage is relatively easy, in front of storage with cache, available CDN, reduce the pressure of storage;

The database reduces the pressure, in front with the cache, the purpose is to reduce the pressure, (in the back is not easy to expand, and inefficient); Of course, you can not cache the database, do static (the contents of the database is exported to HTML, reduce the pressure of the database);

The goal of the most awesome architect and database administrator is to try to get the site's requests out of the database, and 90% to resolve them, but the remaining 10% still can't hold up (the database and storage are pretty fragile because it's extremely difficult to scale).

In fact, 99% of the biggest bottlenecks in Internet sites are in the backend, database and storage. Do operations engineer to play the database, the architecture is particularly simple.

• Addressing data bottlenecks from the architecture illustrates one reason:

Have a problem not to carry on their own, to team spirit;

The database has the pressure to let the front memcache carry, the data static, let the Web server carry;

Similarly, there are problems in the work and do not carry out their own, to play a team role, let the team carry.

1. Introduction to the Database

1) The database is the warehouse that organizes and stores the database according to certain data structure, writes in C and C + +, and supports many programming languages;

2) Application scenario: Small and medium-sized websites;

3) Features:

Advantages: Small size, fast speed, open source code, low overall cost;

Disadvantages: small scale, limited function;

2. Types of databases

Early according to the history of development theory is divided into three kinds: hierarchical database, network-based database, relational database;

• Work Scenario Application classification: relational database, non-relational database (NoSQL database)

Note: Every item we do is close to the internet and the work scene.

3. Relational database:

1) relational database advantages:

The database centralized sharing, the data independence and the abstraction level is high, the user experience is good;

2) Relational Database introduction:

Relational Database model: two-dimensional tabular form (the complex data structure is attributed to two-yuan relationship);

In the relational database, the operation of the data is almost entirely based on one or more relational tables;

3) relational database features:

The ① relational database is similar to the two-dimensional table of the Exel table to represent;

② Access language is the SQL language, Structured Query language to access the data;

③ Typical products: MySQL and Oracle

4. Non-relational database:

• Non-relational databases have also become NoSQL databases, meaning "not only SQL";

Non-relational database is an effective supplement to the traditional relational database, it is not to completely negate the relational database;

Origin

with the rise of the web2.0 website, the non-relational database is produced to compensate for the lack of the dynamic request in the relational database.

More and more dynamic requests, the requirements of the database is more and more high, and the traditional relational database follows the acid theory, the access data is very slow, but also to the disk, so the speed is very slow, non-relational database is born.

• Typical products:

A non-relational database of business: Google's Bigtable;amazon Dynamo;

Open source Non-relational database: Facebook's Cassandra;apache Hbase;redis;mogodb

Noun Explanation: web2.0: Upload to User-themed download (more dynamic applications, larger database pressure)

5. Common relational Database product introduction

1) MySQL Database

2) MariaDB

3) Oracle Database

4) SQL Server (developed in Microsoft environment)

Avoid: Do not mix, mixed with the database is very tricky;

6. The commonly used Non-relational database products:

1) memcache

Memcache is a pure memory cache and is an open-source, high-performance cache system with distributed memory objects. It reduces database load and accelerates dynamic Web applications.

2) Redis

Supports memory caching, persistence, rich data types, cluster support, distributed, support queue.

3) MongoDB

MongoDB is a kind of product between relational database and non-relational database, which is the most feature-rich and relational database in non-relational database. The biggest feature of MONGDB is that it supports a very powerful query language and also supports indexing of data. High performance, easy to deploy, easy to use, easy to store data.

This article is from the "Lanzhi" blog, make sure to keep this source http://7826443.blog.51cto.com/7816443/1706078

MySQL Database < a >