Mysql entertainment explanation table relationship

In the previous chapter we talked about the wide range of applications of databases. Without the database, we may not be able to move forward in the future.

There are quite a lot of boys and girls learning computers now. Especially among the aboriginal Internet users born in the 80s and 90s, many people love to play games. We explain the relationship between tables through the user equipment information in the game.

Withdrawing money from the bank, transferring money, and sending red envelopes are also the most commonly used bank card operations in our daily life. We also use bank card deposits and withdrawals to explain the relationship between tables.

The relationship between equipment and users in the game

A character in the game has a helmet, clothes, boots, weapons, and necklaces.

And, each different weapon will add different attack and defense values. Then we can simulate the table design of the game in this way.

Note: The following is only for everyone to better understand the relationship between the game, users and equipment.

User table

##1 Skeleton King 1 6 2 Chaos Knight 4 2 3 centaur 3 7

User ID	Username	Mask	Boots	Weapon

Equipment table

In the user table, Skeleton King wears the weapon numbered 1 (death mask) in the equipment table and uses the weapon numbered 6 (magic rod).

User 3 (Centaur) used the numbers 3 (Boots of Speed) and 7 (Ghost Scepter) in the equipment table.

This enables some users to wear equipment in the game. If there is no such option in the user's row and column data, there will be no such data.

By adding the attribute value of the equipment to the attribute value of the user's level, different effects such as blood recovery and increased defense value can be achieved when the user wears the equipment.

Opening a bank account, withdrawing cash and reprinting

One of the activities we often perform in our daily life is to use bank cards to pay. In the bank statement, every transaction we make is faithfully recorded. .

Let’s simulate it through a table:

##Equipment ID ##1 Death Mask 10 3 5 2 Escape Dagger 22 4 1 3 Boots of Speed 3 4 5 4 Artist Mask 1 3 4 5 Mage Cloak 5 6 3 6 Magic Wand 13 32 32 7 Ghost Scepter 11 33 45

Equipment name	Recovery Blood	Recovery Magic	Defense

##6222 0202 0002 66014 e10adc3949ba59abbe56e057f20f883e 0 12345.00 2 The above table is designed with the user’s bank card ID, card number, password, whether it is frozen and the balance.

Bank Card ID	Bank Card Number	Password	Whether to freeze	Balance
1
##5423 4321 4567 8889	5bd2026f128662763c532f2f4b6f2476	1	45.58

Scene simulation:

After the user inserts the card and enters the correct password. Then you can withdraw money

1. In social engineering, people like to use the same password. Therefore, the user's password must be encrypted again and cannot be decrypted reversely. Because I am afraid that after seeing a certain user's password, I will use this password to try the user's other bank cards.
2. We stipulate by ourselves: the freezing status can be set to 0 (not frozen) and 1 (frozen). If the bank receives notice from the court. Then set the freeze status to 1. If you have money, you are not allowed to withdraw it. (This business logic needs to be implemented in the program).
3. If the user withdraws money or deposits money, the user's balance will be increased or decreased. At the same time, the records will be recorded in the transaction flow.

Transaction flow sheet

Whenever a user's balance changes, we will faithfully record it in the transaction schedule. Make transactions traceable and traceable.

This simulates the bank's freezing, cash withdrawal, and deposit processes.

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Note:
The password must be encrypted for the user using encryption methods such as md5. The user enters the original password such as: 123456. We use md5 to encrypt the 123456 entered by the user and compare it with the password of the database.
If they match, the password will pass. If they are inconsistent, the user entered the password incorrectly.

This ensures the security of user passwords and prevents insiders from leaking user passwords.
For more password knowledge, we will explain more to you in the next volume and advanced projects.

Continuing Learning Bank card ID 1 1 2

Operation	Location
-1000.00	Beijing Baidu Building ATM
+34000.00	Shanghai Bund xx Bank Business Office
-12.08	Taobao Online Shopping