Detailed explanation of SQL server stored procedures

One ： Overview of stored procedures
1.1 The concept of stored procedure
stored procedure （Stored Procedure） It's precompiling SQL Statement set , These statements are stored in a name （ The name of the stored procedure ） And deal with it as a unit . Stored procedures replace the traditional one by one execution SQL How statements work , A stored procedure can contain queries 、 Insert 、 Delete 、 A series of updates and other manipulation SQL sentence , When this stored procedure is called and executed , These operations will also be performed at the same time .
Stored procedures are similar to procedures in other programming languages , It can take input parameters , And returns multiple values to the calling procedure or batch in the form of output parameters ; Contains information for performing operations in the database （ Including calling other procedures ） Of becomes a statement ; Returns the status value to the calling procedure or batch , To indicate success or failure （ And the reasons for the failure ）.
SQL Server There are three types of stored procedures
1. System stored procedure ： Used to manage SQL Server With stored procedures that display information about databases and users .
2. Custom stored procedures ： The user is in SQL Server By using SQL Statement to create a stored procedure .
3. Extended stored procedure ： Through programming language （ for example C） Create external routines , And put this routine in SQL Server Is used as a stored procedure in .
1.2 Advantages of stored procedures
Some aspects of stored procedures are as follows ：
（1） Stored procedures can be nested , Support code reuse ;
（2） Stored procedures can accept and use parameters to dynamically execute SQL sentence ;
（3） Stored procedures are better than ordinary SQL Statement execution speed is fast . Stored procedures are compiled at the time of creation , Every time it is executed , No need to recompile . and SQL Statements need to be compiled every time they are executed ;
（4） Stored procedures have security features （ For example, authority ） And ownership Links , And certificates that can be attached to them . Users can be authorized to execute stored procedures without having to directly have permissions on the objects referenced in the stored procedures （ It's kind of like JAVA Encapsulation in object-oriented ）.
（5） Stored procedures allow modular programming . Once the stored procedure is created , Then you can call any time in the program . This can improve the maintainability of the application （ It's kind of like JAVA The idea of layered architecture in ）, And allow the application to agree to access the database .
（6） Stored procedures can reduce network traffic . One needs hundreds of lines SQL The operation of statement code can be executed by a statement executing procedure code , Instead of sending hundreds of lines of code over the network .
（7） Stored procedures can enforce application security . Parameterized stored procedures help protect applications from SQL Injection attack .
explain ：SQL Injection It's an attack , It can insert malicious code that will later be passed to SQL Server String for analysis and execution . Any composition SQL Statements should be checked for injection vulnerabilities , because SQL Server All syntactically valid queries received by the executor .
Two ： Create stored procedure
2.1 Use visualization tools to create stored procedures
Every visualization tool may have some differences , So what tools are used to create stored procedures , There should be a lot of resources to find in Baidu. There is no demonstration here

2.2 Use create proc Statement to create a stored procedure
The grammar is as follows
create proc Procedure Proc_Student
@Proc_Son int
as
select * from Student where Sno = @Proc_Son

3、 ... and ： Manage stored procedures
3.1 Execute stored procedures
After the stored procedure is created , Can pass EXECUTE Command execution , It can be abbreviated as EXEC.
1.EXECUTE
EXECUTEyonglai zhixing Transact-SQL Command string in 、 character string 、 Or execute one of the following modules ： System stored procedure 、 User defined stored procedures 、 Scalar valued user-defined functions or extended stored procedures .
2. Use EXECUTE Execute stored procedures
For example, executing stored procedures Proc_Stu
exec Proc_Stu

3.2 View stored procedures
1. Use sys.sql_modules View stored procedure definitions ;
select * from sys.sql_modules

2. Use OBJECT_DEFINITION View stored procedure definitions
OBJECT_DEFINITION(object_id)

3. Use sp_helptext View the definition of a stored procedure
Display the definition of user-defined rules 、 The default value is 、 Unencrypted Transact-SQL stored procedure 、 User defined Transact-SQL function 、 trigger 、 Calculated column 、CHECK constraint 、 View or system object （ Such as system stored procedures ）. The statement is as follows ：
sp_helptext 'Proc_Stu'

3.3 Modify stored procedure
Modifying a stored procedure can change the parameters or statements in the stored procedure , Can pass SQL Statement ALTER PROCEDURE Statements for . Although delete and recreate the stored procedure , You can also achieve the goal of modifying stored procedures , However, all permissions associated with the stored procedure will be lost .
1.ALTER PROCEDURE sentence
ALTER PROCEDURE Statement is used to modify by executing CREATE PROCEDUR Statement creation procedure . When this statement modifies a stored procedure , Permissions will not be changed , It doesn't affect related stored procedures or triggers .
example ： Change the name to “Proc_Stu” Stored procedure .
ALTER PROCEDURE [dbo].[Proc_Stu]
@Son varchar(10)
as
select * from student

3.4 Rename stored procedure
sp_rename 'Proc_Stu','Proc_StuInfo'

Be careful ： Changing any part of the object name can break scripts and stored procedures . It is not recommended to use this statement to rename stored procedures 、 trigger 、 User defined functions or views ; Instead, delete the object , Then recreate the object with a new name .
3.5 Delete stored procedure
DROP PROCENDURE Proc_Student

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Link to the original text ：https://blog.csdn.net/little_jecklove/article/details/108990153
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