Sql--mysql Database Introduction

Statement: The material used in this column is written by the VIP students of the Kay Academy, who has the right to be anonymous and has the final right to interpret the article; The Edith Academy is designed to promote students to learn from each other on the basis of public notes.

Mysql:

Introduced:
What is a database? is a software, can help us to store and extract the data, like in the Java stored variable array and other things are in memory, memory speed, but not for a long time to store, and the advantage of hard disk is the storage time is long, but the speed is particularly slow
Advantage: The ability to quickly find the data we want to optimize storage
Want to save data for a long time can only be stored on the hard disk, when we start the next time, the data read up

The main purpose of the database is to:
1. Data storage
2. Fast Data extraction

The databases in the industry are:
Mysql
Oracle
MS SQL Server
Sybase
DB2

In Zhongguancun can have the database of software to buy, can see its price

What is the main learning database?
Learn SQL statement, is the operation of the database statements, learning database is to learn SQL statements, learn SQL statements, basic all the database operations are similar

We want to the data once, delete, check, change the SQL statements appear to execute, the SQL statement sent to the database can help you execute, the results of the implementation of feedback to your program

DBMS Database Management System
RDBMS-relational database management system
The present way of presenting data is presented in a tabular manner.

What is a relational database, when the storage of things without jinzhao a table to remember, just like the two tables have a corresponding relationship, in a tabular way to present the data is called the relational database

Ordbms Object-relational database management system
That is, you put in the following table is a digital text and ordinary text, that I can put an object in your column, the object can also contain multiple attributes, the form of expression is in the form of a table as the base column has objects, this object is not a Java object, It's about putting some objects in this column, which can show many properties.
Like: It's like a column has an object with three properties in it

DBA database administrator

SQL statements:
Database Operations commands are:
DCL-Database Operation statements
Database system parameter Settings
Start off

DML-Data manipulation statements
INSERT UPDATE DELETE
DQL-Query Operation statement
SELECT

DDL-Data Structure action statement CREATE table
Create a View
Create an index

Sql--mysql Database Introduction