Oracle function trigger

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function

#   Function has return value  return
#  create or replace function func_calsale(gdid orders.gdid%type) return number
as
    salenum number(20);
begin
    select sum(buynum) into salenum from orders o where
    o.gdid=gdid;
    return salenum;
 end;
​
#  @  /opt/my.sql
​
#  select func_calsale(2) from dual;

trigger

# Stored in a database , Stored procedures that are implicitly executed . stay  Oracle8i  Before , Only tables or views are allowed 
 Of  DML  The operation of , And from  Oracle8i  Start , Not only can it support  DML  trigger , It is also allowed to give system events and 
DDL  The operation of 
​
# Triggers implicitly run automatically when an event occurs PL/SQL Block , Cannot receive parameter , Cannot be called .
​
# Whenever a particular data manipulation statement (insert update delete) When issued on a specified table , Oracle Automatically execute the sequence of statements defined in the trigger .

Create table Implement triggers

#  create table orderhistory(oid int primary key,sid int,modifydate date, buynum int);
​
# create sequence seq_oh;
​
#  @ /opt/my.sql
​
#  set serveroutput on
​
#  update orders set buynum=2 where oid=4;
​
#  update orders set buynum=2;
​
#  rollback;
​
#-- on  Tied to the watch 
create or replace trigger trig_order_mod
before update on orders 
-- for each row   Multiple line updates trigger 
for each row 
begin
 dbms_output.put_line('Hello');
 end;
 /
​

Create table 2

create table custs(id int primary key,name varchar(20) not null);
​
create table cards(id int primary key,trantype int,money
number(10,2));
​
alter table cards add custid int not null;
​
alter table cards add constraint FK_cust_card foreign key(custid) references custs(id)
​
#-----------------------------------------------#
# Create sequence 
create sequence seq_cust;
​
create sequence seq_card;
​
@ /opt/my.sql
​
insert into custs values(seq_cust.nextval,'zs');
​
commit;
​
select * from custs;
#-----------------------------------------------#
create or replace trigger trig_bank
after insert on custs
for each row
begin
 insert into cards values(seq_card.nextval,1,1,:new.id);
 end;
 /
#-----------------------------------------------#
desc orderhistory;
​
create sequence seq_his;
​
@ /opt/my.sql
​
select * from orderhistory;
​
#-----------------------------------------------#
create table myorders(id int primary key, ordid int, status int,starttime datetime, overtime datetime);
​
create table xyz(id int primary key, dt timestamp );
​
insert into xyz values(1,sysdate);
​
commit;
​
select * from xyz;
​
alter table xyz modify dt timestamp(2);
​
delete from xyz;
​
commit;
#-----------------------------------------------#
oracle  Timestamp conversion date 
select to_date(dt,'yyyy-MM-dd hh24:mi:ss') from xyz;
​
select to_char(dt,'YYYY-MM-DD hh24:mi:ss') from xyz;
​
select to_date(to_char(dt,'YYYY-MM-DD hh24:mi:ss')) from xyz;
​
select to_timestamp('9999-12-31 23:59:59','YYYY-MM-DD hh24:mi:ss')  from dual;
​
#-----------------------------------------------#
create table myorders(id int primary key,orderid int, status int ,starttime timestamp(0),overtime timestamp(0));
​
desc myorders;
#-----------------------------------------------#
​
select * from xyz where to_char(dt,'YYYY-MM-DD')='2022-06-24';
#-----------------------------------------------#
 Start testing 
@ /opt/my.sql
​
desc myorders;
​
insert into myorders values(1,1,1,sysdate,to_timestamp('9999-12-31 1:0:0','YYYY-MM-DD hh:mi:ss'));
​
rollback;
########  display output 
@ /opt/my.sql
​
select * from myorders;
​
insert into myorders values(1,1,1,sysdate,to_timestamp('9999-12-31 1:0:0','YYYY-MM-DD hh:mi:ss'));
​
insert into myorders values(2,1,2,sysdate,to_timestamp('9999-12-31 1:0:0','YYYY-MM-DD hh:mi:ss'));
​
select * from myorders;
#-----------------------------------------------#
create or replace trigger trig_myorder
before insert on myorders
for each row 
begin
    update myorders set overtime=sysdate where ORDERID=:new.orderid 
    and to_char(overtime,'YYYY-MM-DD')='9999-12-31';
    -- dbms_output.put_line(:new)
​
end;
/
########  It's on it vs Code 

Delete trigger

create or replace procedure proc_myorder
(ordid myorders.orderid%type,ordstatu myorders.status%type)
as
begin
    update myorders set ovetime=sysdate where ORDERID=ordid
    and to_char(ovetime,'YYYY-MM-DD')='9999-12-31';
    insert into myorders values(seq_mo.nextval,ordid,ordstatu
    ,sysdate,to_timestamp('9999-12-31 1:0:0','YYYY-MM-DD hh:mi:ss'));
end;
/
#-----------------------------------------------#
drop trigger trig_myorder;
​
delete from myorders;

Partition

# Partition data 
# Speed up query efficiency 
# The method is as follows 
 Traditional table partition 
2.1.1 Range partitioning range2.1.2
 List partition list2.1.3
 Hash partition hash2.1.4 
 Composite partition  range + list or hash2.2 11g
​
 New feature partitions 
2.1.1 Reference partition  reference
2.1.2  Interval partition interval

Create a partition table

Range partitioning list2.1.3

drop table stus;
​
create table stus(stid int primary key,name varchar(20),age int) 
partition by range(age)(
partition p1 values less than(20) tablespace mydemo,
partition p2 values less than (50) tablespace mydemo,
partition p3 values less than (maxvalue) tablespace mydemo);

# test

insert into stus values(1,'zs',18);
insert into stus values(2,'ls',19);
​
select * from stus partition(p1);
select * from stus partition(p2);
select * from stus partition(p1,p2);
​
​
​

Delete table

drop table stus;

Hash partition hash2.1.4

create table stus (id int primary key,name varchar(20),age number)
partition by hash(name)(
partition p1 tablespace mydemo,
partition p2 tablespace mydemo,
partition p3 tablespace mydemo
);
​
insert into stus values(1,'zs',18);
insert into stus values(2,'zsf',100);
select * from stus partition(p1);
select * from stus partition(p2);
select * from stus partition(p3);
insert into stus values(3,'lisi',22);
insert into stus values(4,'lisiguang',1221);
select * from stus partition(p3);

There are hot issues

 Use the function again hash Law  
 Add salt ？  Random values do tail  

Solve the code

create table stus1(id int primary key,name varchar(20),age int,hashname varchar(30))
partition by hash(hashname)(
partition p1 tablespace mydemo,
partition p2 tablespace mydemo,
partition p3 tablespace mydemo
);
​
insert into stus1 values(1,'zs',10,trunc(dbms_random.value(1,1000))||'zs');

List partition list2.1.3

Tree structure

create table addrs(id int primary key,name varchar(20),subid int);
​
insert into addrs values(1,'chian',0);
insert into addrs values(2,'jiangsu',1);
insert into addrs values(3,'zhejiang',1);
insert into addrs values(4,'nanjing',2);
insert into addrs values(5,'xuzhou',2);
insert into addrs values(6,'hangzhou',3);
insert into addrs values(7,'jiaxing',3);

cascade ( Trees ) Inquire about

Enter a name to display the associated name

The way 1

-- Create a function 
create or replace function fun_linked(city addrs.name%type) return varchar
as
-- Defining variables 
    res varchar(100);
    nm  varchar(20);
    suid varchar(10);
begin
    --res Received incoming city
    res:=city;   
    select name,subid into nm,suid from addrs where name=city;
    --  Start the cycle  ==0 Go straight back to 
    while (suid != 0) loop
        select name,subid into nm,suid from addrs where id=suid;
        -- == hinder res It was the city before  nm It's the city found out later 
    res:= res || ',' || nm ;
    end loop; 
    -- return res There is one or more in the data city
    return res; 
    
end;
/    
#-----------------------------------------------#
@ /opt/my.sql
​
select fun_linked('xuzhou') from dual;
​

The way 2

select * from addrs start with id=1 connect by id=prior subid;
​
select * from addrs start with id=2 connect by prior id=subid;

create or replace function fucs(city addrs.name%type)return 
varchar
as
    flag varchar(100);
    aname varchar(20);
    asubid varchar(20);
begin
    flag:=city;
        select name,subid into aname,asubid
        from addrs
        where name=city;
        while(asubid !=0) loop
            select name,subid into aname,asubid
            from addrs
            where id=asubid;
            flag:=flag || '   +++++   ' || aname
        end loop;
    return flag;
end;
/
​