What a database is, how to connect to something, I don t have a clue at all.

Database,As the name suggests, it is used to store data.,For example, passwords in the game.,Personal information is read in the database.。。。

Commonly used databases are MySQL, SQLSer, Oracle, etc., the first two are generally used by small and medium-sized enterprises, and Oracle is generally used by large enterprises. . .

Install it, take sqlserver as an example, when you log in after installation, choose to log in with a windows account, this is without a password, go in and then find the sa folder on the left like a file manager according to the mark, right-click sa, select properties, pop up the property dialog box, start to change the password, click OK, and then log in again, fill in the sa password with the user name you just modified to log in (I'm talking about sqlserver2008, I don't know about the rest)

Hope...

Let me give you an analogy so that you can easily understand.

Interface display section: It is built with HTML, CSS, JS, JQ and other languages and frameworks. It is a web page that users can see directly.

Take ** as an example, all the ** that you can see when you open the **interface, the text is written in html, css, js, jq.

Logical control section: It is written in PHP language, including some judgments, and the implementation of ** functions requires logical sections. Take ** as an example, you click to buy, prompt to let you log in, you enter the password, enter the correct one, you can place an order normally.

So this prompt allows you to log in, as well as judge to log in to Chen Gong, these logic controls are implemented with PHP.

Data storage section: It is the database used, each ** needs to use the database, and the role of the database is to store data. So first of all, you need to understand what is data?

You register**, let you fill in those passwords, mobile phone numbers, other information, etc. are data, at this time there is a user data table, which is listed, password, mobile phone number, name, etc.;

You fancy an item and place an order to buy it, prompting the item inventory level to -1. This item is also stored in the database, and there is a corresponding item data table, which lists the item's name, **, inventory amount, etc.

To put it simply, the database is a big warehouse, which is used to store all the data, and in this database, there are houses listed in categories to store different data, and these houses are data tables. Some data tables store user information, some store item information, some store transaction records, and some store administrator information.

If you don't understand it, let's take the news network as an example. The database of the news network is relatively simple, and the database of the news network roughly has the following tables: user data table (storing user information), news data table (storing news titles, types, contents, release time, authors, etc.), news category table (news category ID, news category name), news author table (author ID, author name), administrator table (storing administrator data).

You need to have an employee number in the employee table, a department number in the employee table, and an employee number in the salary table as a foreign key.

Design the table that should be done and classify it well.

Connect tables by foreign keys to avoid data redundancy, and write general queries through SQL statements.

The username and password is the username and password that you use to log in to the database, and you usually use the root user login password to set it yourself.

jdbc

Get a connection to operate.

Thank you.

Dude,To use the **connection,The thing you go down is called the driver package,It's filled with**,Just search it on the Internet.,There's a lot of introduction!

Sometimes, you have 10,000 yuan, but you can only do 5,000 yuan because there are still places where you don't have a good budget. But you have 5,000 dollars, and you can't do anything for 10,000 dollars.