Stored procedure test 1 -- first acquaintance of love

##### Write it at the front , Stored procedure is a relatively old sql The language , At present, there are many information about this on the Internet , I also rely on them to learn ( After all, I can reach this level Of , Generally speaking, it takes only two hours to learn a new language ),##### Due to insufficient time precipitation , There are inevitably omissions and mistakes , Therefore, this series of stored procedure articles is not for popularization , Just for my own notes
##### finger heart , Finally bow to the stored procedure

I have been doing big data for many years , I hate stored procedures , Because it is difficult to migrate , The reproducibility is not high , Difficult to develop , There are no clusters and other bad points . But it's a mistake , The project I'm working on now just needs Oracle To realize the calculation and loading of data , Both good and bad things have , There is only a distinction between fit and unfitness , So review the stored procedure , I found that he still has the following advantages （ It has nothing to do with what I have to do now , Yes , I am sincere ！）

1. Fast execution —— Stored procedures are compiled only at creation time , Every time you execute a stored procedure in the future, you don't need to recompile

2. Reduce network traffic —— When doing complex operations on a database , For example, for multiple tables insert、update Transactions can be run together in batches

3. Improve reusability —— Stored procedures can be reused , Improved reusability

4. High maintainability —— Updating stored procedures is usually better than changing 、 Testing and redeploying assemblies takes less time and effort .

5. High safety and reliability —— The authority mechanism of the database itself determines its security

What about stored procedures ？

To put it simply, put more insert etc. DML,drop etc. DDL A precompiled collection of statements executed together , Similar to function , But there is also meaning , Way of execution , The use conditions are different , For example, a stored procedure can call and reference other stored procedures , But functions can only reference other return sets .

That's the definition , Now let's write a simplest stored procedure , It's what we often use hello world

--  Create stored procedures 
CREATE OR REPLACE PROCEDURE testMyProcedure AS
BEGIN
  DBMS_OUTPUT.put_line('Hello World');
END;

--  Run stored procedures , It can also be EXECUTE testMyProcedure;
BEGIN
	testMyProcedure;
END;

Can pass sqlplus Login execution execute xxx To run the , It can also be in IDE such as pl/sql developer Running in begin  xxx; end;

OK, This is the end of the first acquaintance , In the next article, we will introduce the basic architecture by building test tables and testing stored procedures https://mochou.blog.csdn.net/article/details/116612107