Mysql stored procedures and functions

Stored procedures and functions

Stored procedures and functions: A similar procedure in java

• benefit
  • Improve code reusability
  • Streamline operations

During storage

• Meaning: a set of pre-compiled collection of sql statement, understand the process batch statement

• benefit:

  • Improve code reusability
  • Streamline operations
  • Reduce compile times and reduces the number and connect to the database server, improving efficiency

• Creating grammar

  • CREATE PROCEDURE 储存过程名(参数列表)
    BEGIN
    	存储过程体;
    END
    

• Parameter structure

  • Parameter list consists of three parts
    • Parameter name Parameter type Parameter mode
    • IN atuname VARCHAR(20)

• Parameter Mode

  • IN: This parameter can be used as an input
  • OUT: This parameter can be used as an output, the return value is
  • INOUT: This parameter either as an input and as an output, which is the urgent need to pass the parameter value, and can return values

• note:

  • If the bank only one sentence, BEGIN END may be omitted
  • End of the body of the procedure required for each sql statement must semicolon
  • End tag
  • DELIMITER end tag

• transfer

  • CALL 存储过程名(实参列表);
    

• Examples

  • delimiter $
    create procedure adm1()
    begin
    	insert into admin value
        (null,"lxc","123456"),
        (null,"aaa","123456"),
        (null,"bbb","123456"),
        (null,"ccc","123456");
    end $
    

  • call adm1;
    

• Delete stored procedure

  • grammar

    • DROP PROCEDURE 存储过程名;
      

• View information stored procedure

  • SHOW CREATE PROCEDURE 存储过程名;
    

function

• Meaning: a collection of precompiled sql statement, understood as a batch statement

• Feature

  • There is one and only one return value
  • parameter list
    • Parameter name Parameter type
  • Function body: there must be a return statement, if there is no will complain
    • If retuen statement is not placed at the end of the function body not being given, but is not recommended
  • Only one sentence function body, can be omitted degin end
  • Use delimiter set the mark

• grammar

  • CREATE FUNCTION 函数名(参数列表) RETURNS 返回类型
    BEGIN
    	函数体
    END
    

• transfer

  • SELECT 函数名(参数列表);
    

• View function

  • SHOW CREATE FUNCTION 函数名;
    

• Delete function

  • DROP FUNCTION 函数名;