Mysql database operation - stored procedure, view, transaction, index, database backup

1. Data preparation

--  establish student library ：student
create database student default character set utf8 collate utf8_general_ci;
/*  Create student table ：students,  Student number is Sid, The data type is varchar(10), Primary key ,  The name is name, The data type is varchar(10),  The gender is sex, The data type is varchar(1),  Age is age, The data type is int,  Class for class, The data type is varchar(10),  The ID card number is card, The data type is varchar(20),  The city is for city, The data type is varchar(20) */
create table students(
	Sid varchar(10) primary key,
	name varchar(10),
	sex varchar(1),
	age int,
	class varchar(10),
	card varchar(20),
	city varchar(20)
);
--  Insert data into the student table 
insert into students values
('001',' Wang Zhaojun ',' Woman ',30,'3 class ','634101199003157654',' Beijing '),
('002',' Zhugeliang ',' male ',29,'2 class ','110102199104262354',' Shanghai '),
('003',' Ruban master ',' male ',30,'1 class ','820102199003047654',' nanjing '),
('004',' White ',' male ',35,'4 class ','840202198505177654',' anhui '),
('005',' Big Joe ',' Woman ',28,'3 class ','215301199204067654',' tianjin '),
('006',' Sun shangxiang ',' Woman ',25,'1 class ','130502199506137654',' hebei '),
('007',' Hundred Li xuance ',' male ',39,'2 class ','140102198107277654',' shanxi '),
('008',' Little Joe ',' Woman ',25,'3 class ',null,' Henan '),
('009',' Hundred Li keep the promise ',' male ',31,'1 class ','',' hunan '),
('010',' Daji ',' Woman ',24,'2 class ','440701199607147654',' guangdong '),
('011',' Lian po ',' male ',30,'1 class ','110202199005017754',' Beijing '),
('012',' Sun Bin ',' male ',36,'3 class ','650102198401297655',' xinjiang ');
/*  Create a curriculum ：courses  The course number is Cid, The data type is varchar(10), Primary key ,  The course is called Cname, The data type is varchar(10) */
create table courses(
	Cid varchar(10) primary key,
	Cname varchar(10)
);
--  Insert data into the curriculum 
insert into courses values
('01',' Chinese language and literature '),
('02',' mathematics '),
('03',' English '),
('04',' biological '),
('05',' Politics '),
('06',' Geography '),
('07',' Physics ');
/*  Create a score table ：scores,  Student number is Sid, The data type is varchar(10), Student table foreign keys ,  The course number is Cid, The data type is varchar(10), Curriculum foreign key ,  The score is score, The data type is tinyint */
create table scores(
	Sid varchar(10),
	Cid varchar(10),
	score tinyint,
	foreign key (Sid) references students(Sid),
	foreign key (Cid) references courses(Cid)
);
--  Insert data into the score table 
insert into scores values
('001','01',49),
('001','02',75),
('001','03',54),
('001','04',66),
('001','05',59),
('001','06',94),
('002','01',58),
('002','02',57),
('002','03',74),
('002','04',90),
('002','05',55),
('002','06',64),
('003','01',83),
('003','02',73),
('003','04',50),
('003','05',67),
('003','06',87),
('004','01',97),
('004','02',50),
('004','03',56),
('004','04',69),
('004','05',72),
('004','06',51),
('005','01',54),
('005','02',66),
('005','03',61),
('005','05',49),
('005','06',86),
('006','01',97),
('006','02',77),
('006','03',66),
('006','04',76),
('007','01',49),
('007','02',40),
('007','03',99),
('007','04',86),
('007','05',78),
('007','06',55),
('008','01',82),
('008','02',72),
('008','03',98),
('008','05',47),
('008','06',68),
('009','01',84),
('009','02',56),
('009','03',74),
('009','04',64),
('009','05',79),
('009','06',97),
('010','02',85),
('010','03',85),
('010','04',90),
('010','05',93),
('010','06',61),
('011','01',85),
('011','02',63),
('011','03',71),
('011','04',58),
('011','05',80),
('011','06',66);

2. stored procedure

Definition ： A stored procedure is a section with a name sql Code , It consists of one or more SQL A collection of statements , Used to accomplish a specific function together
Create stored procedure
sqlyog grammar ：

delimiter $$
create procedure  Stored procedure name ( Parameters , Parameters )
begin
sql sentence 1;
sql sentence 2;
end$$
delimiter ;

explain ：
delimiter $$ It means to define $$ by SQL Statement Terminator ;
If there is no parameter after the stored procedure name, you may not write the parameter

Navicat grammar ：

create procedure  Stored procedure name ( Parameters , Parameters )
begin
sql sentence 1;
sql sentence 2;
end

practice 1：

--  Create stored procedure stu_pro, Content is query students All data of table （Navicat）
create procedure stu_pro()
begin
select * from students;
end;

Query stored procedures for all databases
grammar ：

show procedure status;

practice 1：

--  Query stored procedures for all databases 
show procedure status;

A stored procedure that queries a database
grammar ：

show procedure status where db=' Database name ';

practice 1：

--  Inquire about student Stored procedure of database 
show procedure status where db='student';

Query the detailed definition information of the stored procedure
grammar ：

show create procedure  Database name . Stored procedure name ;

practice 1：

--  The query stored procedure name is stu_pro Detailed definition information of 
show create procedure student.stu_pro;

Calling stored procedure
grammar ：

call  Stored procedure name ();

practice 1：

--  Calling stored procedure stu_pro
call stu_pro();

Delete stored procedure
grammar ：

drop procedure  Stored procedure name ;

Be careful ： When deleting a stored procedure, you do not need to write the parentheses after the stored procedure name
practice 1：

--  Delete stored procedure stu_pro
drop procedure stu_pro;

3. View

Definition ： The view is based on SQL A visual virtual table of the result set of the statement
Create view
grammar ：

create view  View name  as sql sentence ;

practice 1 ：

--  Create a view named stu_nan, Content is query students Table all the information about boys 
create view stu_nan as
select * from students where sex=' male ';

Use view
grammar ：

select * from  View name ;

explain ： You can treat the view as a table , But only read-only access to data （ We can only check , Can't add 、 Change 、 Delete ）
practice 1：

--  Use view stu_nan
select * from stu_nan;

Delete view
grammar ：

drop view  View name ;

practice 1：

--  Delete view stu_nan
drop view stu_nan;

practice 2：

--  If the view stu_nan Delete if it exists 
drop view if exists stu_nan;

4. Business

Definition ： A transaction is a sequence of operations on a database , It is an indivisible work unit , Or all the operations in this sequence will be executed , Or none at all
characteristic ：
Atomicity ： All operations in a transaction are indivisible in the database , Or all , Or none at all ;
Uniformity ： Transactions are executed sequentially , The intermediate state between the start and end of a transaction will not be seen by other transactions ;
Isolation, ： If there are multiple transactions executing concurrently , Changes made by each transaction must be isolated from other transactions ;
persistence ： After the transaction completes , Changes to database data are persisted
grammar ：

--  Start business 
begin;
--sql Execute statement 
sql sentence ;
--  Roll back the transaction 
rollback;
--  Commit transaction 
commit;

Be careful ： If only the transaction starts , But there is no rollback transaction or commit transaction , By default, the transaction is rolled back
practice 1：

--  Start business 
begin;

--  Change Wang Zhaojun's age to 35, And change Wang Zhaojun's Chinese score to 95
update students set age=35 where name=' Wang Zhaojun ';
update scores set score=95 where Sid in (select Sid from students where name=' Wang Zhaojun ')
and Cid in (select Cid from courses where Cname=' Chinese language and literature ');

--  Roll back the transaction 
rollback;

--  Commit transaction 
commit;

understand ： A transaction needs to start first （begin）, tell sql I'm going to start a business , And then execute insert、update、delete sentence , The results of the execution are placed in the cache （ At this time, the data in the cache is used to query Wang Zhaojun's age and language scores ）, But if you directly open the table to view the data, you will find that there are no changes , Because it hasn't been submitted yet , When you submit a transaction , To really modify the table , otherwise sql It will be rolled back automatically before the transaction starts , That is, nothing has changed .

5. Indexes

Definition ： Index is help MySQL Data structure for efficient data acquisition . Generally speaking, an index is like a book catalog , Greatly accelerate the query speed of the database
Advantages and disadvantages ：
advantage ： Greatly improved select Query speed of statement
shortcoming ： Will slow down the update of tables , for example ：insert、update、delete operation
Create index
grammar ：

create index  The index name  on  Table name ( Field name ( length ));

Be careful ：
If the specified field is a string , You need to specify the length , The recommended length is the same as the length when defining the field ;
If the field type is not a string , It is not necessary to fill in the length part ;
For primary keys , The system will automatically create an index , That's the primary key index
practice 1：

--  to students Tabular name Field creation index name_index
create index name_index on students(name(10));

Look at the index
grammar ：

show index from  Table name ;

practice 1：

--  see students All indexes of the table 
show index from students;

Delete index
grammar ：

drop index  The index name  on  Table name ;

practice 1：

--  Delete students Index of tables name_index
drop index name_index on students;

explain ： The field name is required to create the index , If a table has an index , As long as you use this field in the query criteria , Then it will automatically use the index

6. Database backup

command ：

mysqldump -u user name  -p password  -A > / The file path to store / File name .sql