以下的文章主要介绍的是MySQL数据库的基本知识,其中包括对MySQL数据库的创建,以及对一些相关的数据类型描述,其中还涉及到表的创建,以下就是文章的详细内容描述,望你会有所收获。 MySQL数据库安装 最好改变字符集UTF8 创建数据库 createdatabasemydata;
以下的文章主要介绍的是MySQL数据库的基本知识,其中包括对MySQL数据库的创建,以及对一些相关的数据类型描述,其中还涉及到表的创建,以下就是文章的详细内容描述,望你会有所收获。
MySQL数据库安装 最好改变字符集UTF8
创建数据库
<ol class="dp-xml"> <li class="alt"><span><span>create database mydata; </span></span></li> <li><span>use mydata; </span></li> </ol>
数据类型 int double char varchar datetime longtext
创建表 create table dept
<ol class="dp-xml"> <li class="alt"><span><span>( </span></span></li> <li><span>deptno int primary key, </span></li> <li class="alt"><span>dname varchar(14), </span></li> <li><span>loc varchar(13) </span></li> <li class="alt"><span>); </span></li> <li class="alt"><span>create table emp </span></li> <li><span>( </span></li> <li class="alt"><span>empno int primary key, </span></li> <li><span>ename varchar(10), </span></li> <li class="alt"><span>job varchar(15), </span></li> <li><span>mgr int, </span></li> <li class="alt"><span>hiredate datetime, </span></li> <li><span>sal double, </span></li> <li class="alt"><span>deptno int, </span></li> <li><span>foreign key (deptno) references dept(deptno) </span></li> <li class="alt"><span>); </span></li> </ol>
MySQL数据库执行脚本文件.sql \. 文件路径 或 source 文件路径
?
sql文件中 -- 注释
MySQL管理软件 MySQL administrator,toad for MySQL
查看数据库 show databases;
查看表 show tables;
查看表结构 desc dept;
插入数据
<ol class="dp-xml"> <li class="alt"><span><span>intsert into dept values(1,'a','a'); </span></span></li> <li><span>commit; </span></li> </ol>
分页 select * from dept order by deptno desc limit 3,2; (从第三条往后数两条)
自增 create table article
<ol class="dp-xml"> <li class="alt"><span><span>( </span></span></li> <li><span>id int primary key auto_increment, </span></li> <li class="alt"><span>title vachar(255) </span></li> <li><span>); </span></li> <li class="alt"><span>insert into article values(null,'a'); </span></li> <li><span>insert into article(title) values('c'); </span></li> </ol>
日期处理
获取当前日期 select now();
转化字符串 select date_format(now(),'%Y-%m-%d %H:%i:%s');
<ol class="dp-xml"> <li class="alt"><span>jdbc连接MySQL </span></li> <li> <span>Connection </span><span class="attribute">conn</span><span>=</span><span class="attribute-value">null</span><span>; </span> </li> <li class="alt"> <span>Statement </span><span class="attribute">stmt</span><span>=</span><span class="attribute-value">null</span><span>; </span> </li> <li> <span>ResultSet </span><span class="attribute">rs</span><span>=</span><span class="attribute-value">null</span><span>; </span> </li> <li class="alt"><span>try{ </span></li> <li> <span>Class.forName("com.</span>MySQL<span>.jdbc.Driver").newInstance(); </span> </li> <li class="alt"> <span class="attribute">conn</span><span>=</span><span class="attribute-value">DriverManager</span><span>.getConnection("jdbc:</span>MySQL<span>://localhost/test? </span><span class="attribute">user</span><span>=</span><span class="attribute-value">root</span><span>&</span><span class="attribute">password</span><span>=</span><span class="attribute-value">root</span><span>"); </span> </li> <li> <span class="attribute">stmt</span><span>=</span><span class="attribute-value">conn</span><span>.createStatement(); </span> </li> <li class="alt"> <span class="attribute">rs</span><span> = </span><span class="attribute-value">stamt</span><span>.executeQuery(sql); </span> </li> <li><span>} </span></li> <li class="alt"><span>catch(Exception e){} </span></li> <li><span>finally{ </span></li> <li class="alt"><span>try{ </span></li> <li> <span>if(rs!=null){rs.close; </span><span class="attribute">rs</span><span>=</span><span class="attribute-value">null</span><span>;} </span> </li> <li class="alt"> <span>if(stat!=null){stat.close; </span><span class="attribute">stat</span><span>=</span><span class="attribute-value">null</span><span>;} </span> </li> <li> <span>if(conn!=null){conn.close; </span><span class="attribute">conn</span><span>=</span><span class="attribute-value">null</span><span>;} </span> </li> <li class="alt"><span>} </span></li> <li><span>catch(SQLException e){ </span></li> <li class="alt"><span>e.printStackTrace(); </span></li> <li><span>} </span></li> <li class="alt"> <span>} </span><span> </span> </li> </ol>
以上的相关内容就是对MySQL数据库知识的介绍,望你能有所收获。

The main role of MySQL in web applications is to store and manage data. 1.MySQL efficiently processes user information, product catalogs, transaction records and other data. 2. Through SQL query, developers can extract information from the database to generate dynamic content. 3.MySQL works based on the client-server model to ensure acceptable query speed.

The steps to build a MySQL database include: 1. Create a database and table, 2. Insert data, and 3. Conduct queries. First, use the CREATEDATABASE and CREATETABLE statements to create the database and table, then use the INSERTINTO statement to insert the data, and finally use the SELECT statement to query the data.

MySQL is suitable for beginners because it is easy to use and powerful. 1.MySQL is a relational database, and uses SQL for CRUD operations. 2. It is simple to install and requires the root user password to be configured. 3. Use INSERT, UPDATE, DELETE, and SELECT to perform data operations. 4. ORDERBY, WHERE and JOIN can be used for complex queries. 5. Debugging requires checking the syntax and use EXPLAIN to analyze the query. 6. Optimization suggestions include using indexes, choosing the right data type and good programming habits.

MySQL is suitable for beginners because: 1) easy to install and configure, 2) rich learning resources, 3) intuitive SQL syntax, 4) powerful tool support. Nevertheless, beginners need to overcome challenges such as database design, query optimization, security management, and data backup.

Yes,SQLisaprogramminglanguagespecializedfordatamanagement.1)It'sdeclarative,focusingonwhattoachieveratherthanhow.2)SQLisessentialforquerying,inserting,updating,anddeletingdatainrelationaldatabases.3)Whileuser-friendly,itrequiresoptimizationtoavoidper

ACID attributes include atomicity, consistency, isolation and durability, and are the cornerstone of database design. 1. Atomicity ensures that the transaction is either completely successful or completely failed. 2. Consistency ensures that the database remains consistent before and after a transaction. 3. Isolation ensures that transactions do not interfere with each other. 4. Persistence ensures that data is permanently saved after transaction submission.

MySQL is not only a database management system (DBMS) but also closely related to programming languages. 1) As a DBMS, MySQL is used to store, organize and retrieve data, and optimizing indexes can improve query performance. 2) Combining SQL with programming languages, embedded in Python, using ORM tools such as SQLAlchemy can simplify operations. 3) Performance optimization includes indexing, querying, caching, library and table division and transaction management.

MySQL uses SQL commands to manage data. 1. Basic commands include SELECT, INSERT, UPDATE and DELETE. 2. Advanced usage involves JOIN, subquery and aggregate functions. 3. Common errors include syntax, logic and performance issues. 4. Optimization tips include using indexes, avoiding SELECT* and using LIMIT.


Hot AI Tools

Undresser.AI Undress
AI-powered app for creating realistic nude photos

AI Clothes Remover
Online AI tool for removing clothes from photos.

Undress AI Tool
Undress images for free

Clothoff.io
AI clothes remover

AI Hentai Generator
Generate AI Hentai for free.

Hot Article

Hot Tools

Safe Exam Browser
Safe Exam Browser is a secure browser environment for taking online exams securely. This software turns any computer into a secure workstation. It controls access to any utility and prevents students from using unauthorized resources.

Notepad++7.3.1
Easy-to-use and free code editor

MinGW - Minimalist GNU for Windows
This project is in the process of being migrated to osdn.net/projects/mingw, you can continue to follow us there. MinGW: A native Windows port of the GNU Compiler Collection (GCC), freely distributable import libraries and header files for building native Windows applications; includes extensions to the MSVC runtime to support C99 functionality. All MinGW software can run on 64-bit Windows platforms.

DVWA
Damn Vulnerable Web App (DVWA) is a PHP/MySQL web application that is very vulnerable. Its main goals are to be an aid for security professionals to test their skills and tools in a legal environment, to help web developers better understand the process of securing web applications, and to help teachers/students teach/learn in a classroom environment Web application security. The goal of DVWA is to practice some of the most common web vulnerabilities through a simple and straightforward interface, with varying degrees of difficulty. Please note that this software

PhpStorm Mac version
The latest (2018.2.1) professional PHP integrated development tool