Data set concept MySQL

The concept of a data set

Open Source : MySQL

Efficient :

High cost performance

Database , means to be stored together in a certain way. , can be shared for multiple users , features with near-possible small redundancy . are applications that are independent of each other data collection

issues with file system Management :

Inconsistent data redundancy

Big Data Access difficulties

Data isolation

Integrity and Atomicity

Concurrent Access Exceptions

Security issues

Enable data sharing

Reduce the redundancy of data

Centralized control of data implementation

Consistency of data

Failure recovery

Database , warehouse where data is stored

DBMS Database management system can operate and manage database of large-scale software abbreviation DBMS

Hierarchical Model :

A model for organizing database data in a hierarchical form

Disadvantages : Redundant Data

Mesh Model :

A model for organizing databases according to the shape of a network structure

Disadvantages : Late Maintenance difficulties

Relational Model :RDBMS

RDBMS By default, it refers to DBMS

E-r Model:

Entity : Data Objects

Contact : represents an association between one or more entities

Properties : An attribute of an entity

Concept : Database management System , Database Library , data sheets, data (Records), Fields

SQL Statements:

The language of structured queries

SQL Type:

DML : Data Manipulation Language : used to manipulate data in the database

DDL : Data Description Language : used to build the database , Defining Data Relationships

DCL : Data Control Language : permissions to control the database build

Relational data Structures :

file Logic :

Upper : file

Bottom : Binary is stored in the data block of the hard disk

Middle tier : File System

Database Logical Relationships:

Upper : Data Sheet

Bottom : File

Middle tier : Storage Engine

Storage Engine: Provides methods for storing, creating, updating, and querying data

Mysql

Nyisam

Default engine, insert, and query Xu Ju faster

Features that do not support things, row-level locks, and foreign key constraints

Things:

some batch processing of SQL statements, in order to ensure data atomicity

Lock:

Row-level Locks: less conflict, slower speed

Table-level locks: conflicting, fast

Page-level Lock: compromise Solution

Constraints:

Domain constraints: Constraints on data types

FOREIGN KEY constraints: referential integrity constraints

INHDDB:

Supports functions such as things, row-level locks, and foreign key constraints

MEMORY:

Working in memory. Data is saved by hashing. Fast, unable to permanently save data.

Storage and querying of data

Storage Manager

To implement the storage function:

through the structure of the DDL creation data table

in passing DML to save data

Things Manager

Provide the function of things

File Manager

Save database data and file correspondence

Permissions and integrity Manager

Set storage Permissions

Buffer Manager

Managing Buffer Space

Query Manager

To implement the function of the query:

Receive query requests from users, understand user query requests

Submits the query request to the storage Manager and implements the final storage.

DDL,DML interpreter

Query execution engine

Apacheprefork worker

A process processes a request

A thread processes a request

A thread handles a request to a

Working mode of single-process multithreading

Daemon Threads

Application thread (user thread)

CPU- Intensive Services

MySQL optimization:

1. Vertical expansion

2. Thread Reuse

3. Cache

NoSQL(memcacheredismongodb)

Disadvantages:

SMP symmetric multi-processor architecture

Server 16CPU

One request 100G

1cpu15cpu

three requests 100G

1CPU 1 Quests

Partition, sub-table, read/write separation

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Data set concept MySQL