current position:Home>[review JS] to consolidate the foundation day23- front end, you should also know some databases
[review JS] to consolidate the foundation day23- front end, you should also know some databases
2021-08-27 05:43:39 【xn213】
This is my participation 8 The fourth of the yuegengwen challenge 23 God , Check out the activity details :8 Yuegengwen challenge
*** What I learned today : ( Understand database related issues
) ! Check for defects and make up for omissions ! ***
It can be used as a learning route for beginners , Please refer to , Learning progress is not particularly in a hurry ! Ongoing update Combine your own understanding , Simple and comprehensive summary in vernacular
JavaScript
Basic knowledge points in the learning process , Facilitate deeper understanding !
Let's start today's study ! ' Only by laying a solid foundation can we build a tall building '! come on. ! take sth. seriously !!
1、 database
database : A warehouse for storing data U disc Hard disk
Common database languages :
- sqlServer
- mysql
- oracle
- db2
The data stored in the database are structured data .
for example :
Hello everyone , My name is XXX I graduated from Tsinghua University Computer science I don't have a girlfriend right now Welcome to be good friends with you .
full name | Gender | Current address | Graduation school | major |
---|---|---|---|---|
So and so | male | Beijing | tsinghua | Computer |
So and so | male | Beijing | Peking University | Communication engineering |
structured :
Data in the database It exists in the form of tables
Relational database : Each database consists of multiple tables , A table consists of multiple rows and columns
The title of each column is called the field title , The corresponding content is table data
Storing data :
First step : Create database
Code implementation : create database Database name
The second step : Create table
create table Table name
(
Field name type ,
Field name type ,
....
)
Copy code
The third step : The data in the table is analyzed increase Delete Change check
- increase :insert into Table name ( Field 1, Field 2,...)values( value 1, value 2,...)
Be careful : The field data added by the primary key is ignored and left blank If the type of value is character , The value must be quoted
-
Delete : delete from Table name where Conditions
-
Condition statement :
- Is equal to use =
- Show and use and
- Express or use or
- If the condition field value is a character Must be quoted
-
-
Change :
update Table name set Field = The new value , Field = The new value where Conditions
-
check :
- select * from Table name Query all field data in the table
- select Field name , Field name 2 from Table name Query the specified field
data type :
int Represents integer data char(100) Indicates the character type varchar(100)
Primary key : primary key characteristic : Data cannot be repeated ( Have uniqueness )
Usually in a table Number The field is the primary key Generally, the primary key is self incrementing
How to set the primary key :
create table Table name
(
sid int primary key auto_increment sid Field is Primary key And it's self increasing
)
Copy code
php How to operate the database
Client submits data to server :
- Form transfer value name
- Hyperlink pass value
<a href="xxx.php?id=213">
- ajax Passing data to the server jsonp Request interface
php Operating database steps :
- Select data source localhost
- Set up the database
- Determine character encoding Prevent confusion code
mysql_query('set names utf8')
- To write
sql
sentence - perform
sql
sentencemysql_query
- Return execution result
Notice : come on. , Dream catcher
Learning is an ongoing process , Hold the line , There must be gains !
Accumulate over a long period , Consolidate the foundation , Enter the factory early !
It's not easy to insist , It's not easy to stick to it , you are so good !
Calm Down & Carry On!
Read more :
Previous update review
【 Relearning JS】 Learn to consolidate the foundation series every day :
【day2】 Various operators 、 【day3】 data type 、 【day4】 Loop structure & Conditional statements 、 【day5】 function ( a key )、 【day6】 Scope & event 、
【day7】 object & Array method summary 、 【day8】 String method & Partial sorting 、
【day9】Math object & Packaging function 、 【day10】BOM- Browser object model 、
【day11】DOM- Document object model 、
【day12】Event The event object is first known ( One )、 【day13】Event The event object is first known ( Two )、
【day14】 Event delegation & Drag and drop principle 、
【day15】 Drag implementation & Regular initial knowledge 、 【day16】 Regular concrete method 、
【day19】Js Encapsulation of motion function
More expectations on the road ... A long way to go ==-..-==
copyright notice
author[xn213],Please bring the original link to reprint, thank you.
https://en.qdmana.com/2021/08/20210827054336282a.html
The sidebar is recommended
- Crazy blessing! Tencent boss's "million JVM learning notes", real topic of Huawei Java interview 2020-2021
- JS JavaScript how to get the subscript of a value in the array
- How to implement injection in vuex source code?
- JQuery operation select (value, setting, selected)
- One line of code teaches you how to advertise on Tanabata Valentine's Day - Animation 3D photo album (music + text) HTML + CSS + JavaScript
- An article disassembles the pyramid architecture behind the gamefi outbreak
- BEM - a front-end CSS naming methodology
- [vue3] encapsulate custom global plug-ins
- Error using swiper plug-in in Vue
- Another ruthless character fell by 40000, which was "more beautiful" than Passat and maiteng, and didn't lose BMW
guess what you like
-
Huang Lei basks in Zhang Yixing's album, and the relationship between teachers and apprentices is no less than that in the past. Netizens envy Huang Lei
-
He was cheated by Wang Xiaofei and Li Chengxuan successively. Is an Yixuan a blessed daughter and not a blessed home?
-
Zhou Shen sang the theme song of the film "summer friends and sunny days" in mainland China. Netizen: endless aftertaste
-
Pink is Wangyuan online! Back to the peak! The new hairstyle is creamy and sassy
-
Front end interview daily 3 + 1 - day 858
-
Spring Webflux tutorial: how to build reactive web applications
-
[golang] walk into go language lesson 24 TCP high-level operation
-
August 23, 2021 Daily: less than three years after its establishment, Google dissolved the health department
-
The female doctor of Southeast University is no less beautiful than the female star. She has been married four times, and her personal experience has been controversial
-
There are many potential safety hazards in Chinese restaurant. The top of the program recording shed collapses, and the artist will fall down if he is careless
Random recommended
- Anti Mafia storm: He Yun's helpless son, Sun Xing, is destined to be caught by his dry son
- Introduction to flex flexible layout in CSS -- learning notes
- CSS learning notes - Flex layout (Ruan Yifeng tutorial summary)
- Today, let's talk about the arrow function of ES6
- Some thoughts on small program development
- Talk about mobile terminal adaptation
- Unwilling to cooperate with Wang Yibo again, Zhao Liying's fans went on a collective strike and made a public apology in less than a day
- JS function scope, closure, let, const
- Zheng Shuang's 30th birthday is deserted. Chen Jia has been sending blessings for ten years. Is it really just forgetting to make friends?
- Unveil the mystery of ascension
- Asynchronous solution async await
- Analysis and expansion of Vue infinite scroll source code
- Compression webpack plugin first screen loading optimization
- Specific usage of vue3 video play plug-in
- "The story of huiyeji" -- people are always greedy, and fairies should be spotless!
- Installing Vue devtool for chrome and Firefox
- Basic usage of JS object
- 1. JavaScript variable promotion mechanism
- Two easy-to-use animation JS that make the page move
- Front end Engineering - scaffold
- Java SQL Server intelligent fixed asset management, back end + front end + mobile end
- Mediator pattern of JavaScript Design Pattern
- Array de duplication problem solution - Nan recognition problem
- New choice for app development: building mobile applications using Vue native
- New gs8 Chengdu auto show announces interior Toyota technology blessing
- Vieira officially terminated his contract and left the team. The national security club sent blessings to him
- Less than 200000 to buy a Ford RV? 2.0T gasoline / diesel power, horizontal bed / longitudinal bed layout can be selected
- How does "heart 4" come to an end? Pinhole was boycotted by the brand, Ma Dong deleted the bad comments, and no one blessed him
- We are fearless in epidemic prevention and control -- pay tribute to the front-line workers of epidemic prevention!
- Front end, netty framework tutorial
- Xiaomi 11 | miui12.5 | android11 solves the problem that the httpcanary certificate cannot be installed
- The wireless charging of SAIC Roewe rx5 plus is so easy to use!
- Upload and preview pictures with JavaScript, and summarize the most complete mybatis core configuration file
- [25] typescript
- CSS transform Complete Guide (Second Edition) flight.archives 007
- Ajax foundation - HTTP foundation of interview essential knowledge
- Cloud lesson | explain in detail how Huawei cloud exclusive load balancing charges
- Decorator pattern of JavaScript Design Pattern
- [JS] 10. Closure application (loop processing)
- Left hand IRR, right hand NPV, master the password of getting rich