[complete installation package & tutorial] sqlserver basic installation_ Sqlserver completely uninstalled_ Sqlserver custom installation_ Getting started with sqlserver_ SQLSERVER database

　　 Today's arrangement for you is sqlserver Super detailed installation and uninstallation tutorial , Let's get started ~【 Complete installation package & course 】sqlserver Foundation installation _sqlserver Uninstall completely _sqlserver Custom installation _sqlserver introduction _sqlserver database https://www.bilibili.com/video/bv1oN4y1M7kz

---

　　Java There are many powerful classes for developers , These classes are placed in separate packages , along with JDK Release together , be called Java Class library or Java API.

　　API(Application Programming Interface, Application programming interface ) It's a general concept .

　　 For example, I wrote a class , We can get all kinds of hardware information of the computer , It's powerful and stable , If your project also needs such a function , Then you don't have to write your own code , Just use my class directly . however , My class code is very complex , It's not realistic for you to read through the code , And I don't want you to see my code ( You don't have to and don't want to read this obscure code ), I want to protect my copyright , What shall I do? ?

　　 I can compile my class first , With a document , Tell you how to use my class , What are the methods and properties , All you need to do is follow the instructions in the document , It saves you time to read the code , It also protects my copyright . for example , obtain CPU Method of information ：

　　getCpuInfo(int cpuType);

　　 So that's one API. in other words , How to use the classes described in this document , It's called API.

　　 I can also develop a software , It's used to clean up the junk files in the computer , I'm more public spirited , I want more developers to use my software , I will release the software with an instruction document , Tell you how to call in your own program , This is also called API.

　　Java There are many packages in the class library ：

　　 With java.* The first is Java The core of Pericardium , All programs use the classes in these packages ;

　　 With javax.* At the beginning is the expansion pack ,x yes extension It means , That's extension . although javax.* It's right java.* Optimization and expansion of , But because of javax.* More and more , Many programs depend on javax., therefore javax.  Also nuclear Part of the heart , Along with JDK Release together .

　　 With org.* At the beginning are packages released by various organizations , Because these organizations are very influential , Their code quality is very high , Therefore, some of the commonly used classes developed by them are also included JDK Release together .

　　 In terms of package naming , In order to prevent duplicate names , There is a convention ： Everyone starts with the reverse form of their own domain name to name the package they developed , For example, Baidu will release packages with com.baidu.* start ,w3c The package released by the organization will use org.w3c.* start , The package released by wechat school will be net.weixueyuan.* start ……

　　 The domain name suffix of an organization is generally org, The suffix of the company's domain name is com, It can be said that org.* The first package is a package released by a non-profit organization , They are generally open source , You can use it in your own products for free , Don't worry about infringement , And then com.* The first packages are often released by for-profit companies , There may be copyright issues , Pay attention when using .