Database---Create functions, store functions, trigger instances

1. Create a function

function float float  floatbegin    # This function is in the body range, so-called "programming Environment"    # "define" session variables and assign values    return @result; End;

function float float  floatbegin    # This function is in the body range, so-called "programming Environment"    #  This range can be used with ordinary variables, already various flow control structures    declarefloatdefault 0;    # define common variables and set initial values    Set result = X*x + y*y;     return result; End;

2, the creation process:

This stored procedure is intended for passing two data and inserting the two data into table enum_test.

CREATE PROCEDURE  pro1 (n int, Xuanxiang varchar)begin    INSERT INTO enum_test (ID, Xuanxiang) VALUES ( N, Xuanxiang); End;

3. Stored procedure with out function

float float float ) begin    = Getpingfanghe (z1, Z2); # Call the function to calculate the sum of squares    POW (@pingfanghe, 0.5); End ; // when the stored procedure is called, the 3rd argument must be a variable

4. Using the Select stored procedure

CREATE PROCEDURE  gettables () begin    * from enum_test;     * from set_test;     * from tab5; End

5, define a trigger, so that the trigger can be inserted in the TAB5 data,
Automatically inserts a piece of data into another table for use by a "foreign partner".
①TAB5 fields: ID, F1, F2, F4, Id2;
② field of another table to be inserted: ID, F1, f2

Create trigger Getsubdata after insert on TAB5 for each  row begin    #set @id = new.id;    #new在触发器中是特定关键字,                        #代表 "data row just inserted", which represents the ID value of the row data    #set @v1 = new.f1;    #新插入数据的f1字段的值    #set @v2 = new.f2;    #新插入数据的f1字段的值    INSERT INTO tab5_sub (F1, F2) values (NEW.F1,NEW.F2); end;

Database---Create functions, store functions, trigger instances