How to determine if the old mysq database was uninstalled successfully

There is no mysql service in the service.

MySQL security settings, including setting the root password, deleting empty users, and opening remote access to the root account.

c：\>e：\mysql\bin\mysql -u root

mysql> use mysql

mysql> select user,host,password from user;

The results of the inquiry can be seen as follows:

user host password

root localhost

rootlocalhost

Delete the empty mysql account > delete from user where user='';

Change host= to % or native IP for remote access to the database.

mysql> update user set host = '%'

where host='';

Set root@localhsot, root@% password:

mysql> update user set password = password('newpwd')

where host = '%';

mysql> update user set password = password('newpwd')

where host = 'localhost';

Or just use the following command to name both roots at the same time.

mysql> update user set password = password('newpwd')；(Not recommended).

After updating the password, you must use flush privileges to have the server re-read the authorization table. Otherwise, the changes will not be used until the server is restarted.

1. How can I set "root password is empty" unsuccessfully? What's the use of setting it to empty? 2. What else do I need to configure after installing mysql?

3. How to use MySQL to create a table and import the database into Eclipse? I'm working on a student registration management system, and there are always errors in the database connection.

1. Specify the character set UTF-8 when creating a table

create table table name.

id` tinyint( 255 ) unsigned not null auto_increment primary key ,`content` varchar( 255 ) not null)

default character set = utf8;

2. Change the character set of the table to UTF-8:

alter table table name convert to character set utf8;

If the default character set of MySQL is GBK, and the database is not specified as UTF-8 when creating the database, then the default character set of the database is GBK, and the same is true for tables in the database.

create database database name character set utf8;

create table message(

id int(10) auto_increment primary key not null,username varchar(20) not null,message varchar(1024) not null,time datetime not null )

engine= myisam character set utf8 ;

The startup screen looks like this. Click on the purple box and it will log you in. After logging in, here's what we need, what we need is schemas. Click the purple box. Then it's time to create databases and tables.

First, open MySQL Workbench and double-click to open it. After opening, the screen is displayed as follows, then select the DB instance and double-click to log in. The instance of the database in the diagram is local instance mysql57

Then, enter your username.

and password to log in. As shown in the figure below:

After successful login, the interface looks like this. Zone 1 displays the list of databases that have been created on the database server. Area 2 is a list of operations on the database. Region 3 is the SQL instrument and execution environment, and Region 4 is the list of execution results.

ctrl+enter）。After the execution is successful, the query results are displayed in the list below.

When you're done using it, just exit it, and remember to turn off the MySQL service if you don't need to follow up on the database.

Hello, int(m), integer(m) 32-bit integer (4 bytes.

In fact, this m has nothing to do with the range that int can represent, as long as you choose int, int is represented by 4 bytes, 1 byte 8 bits, if the range that can be represented when representing an unsigned number is 0 --232-1, you can store any number in this range.

But it's not that it has nothing to do with the representation, there is a zerofll in mysql, when you select 0 when you create a table, the storage will be very different, if you choose int(4) and you store 12, then the database is stored 0012, if you fill in 12345, it will be stored as it is.

There's no need to uninstall, you don't want to boot it up, you can't start it, and it won't have any effect. I don't usually use him to manage MySQL services.