Since complex query takes long time to execute so I want to create a table to keep for future use, I don't want to execute it again. so my idea is that I want to create a table by insert query result into it.
The below is my sample code. It is not working it is just my idea. Thanks
DECLARE
with tab_emp as (
select * from employees
),
tab_dept as
(select * from departments)
procedure create_tab_from_query IS
begin
EXECUTE IMMEDIATE ('create table mytest as select * from '|| tab_emp || ' where 1=0');
end create_tab_from_query;
BEGIN
create_tab_from_query;
dbms_output.put_line(abc);
END;
/
This works:
SQL> with t2 as (select * from t) select * from t2;
L A
--------- ------------------------------------------------------
RUS Русский
But you cannot use WITH in a CREATE TABLE statement as you would like to use.
This cannot work:
SQL> with t2 as (select * from t) create table t3 as select * from t2;
with t2 as (select * from t) create table t3 as select * from t2
*
ERROR at line 1:
ORA-00928: missing SELECT keyword
You should try something simpler without WITH clause:
SQL> create table t3 as select * from t;
Table created.
In your case your PL/SQL code could be simplified this way:
SQL> --
SQL> BEGIN
2 EXECUTE IMMEDIATE ('
3 create table mytest as select * from employees where 1=0');
4 dbms_output.put_line('abc');
5 END;
6 /
abc
PL/SQL procedure successfully completed.
I don’t know how to create AFTER INSERT TRIGGER with the condition Table_1.Table_2_ID = Table_2.ID .
CREATE OR REPLACE TRIGGER Table_2_TRG
AFTER INSERT
ON Table_1
FOR EACH ROW
BEGIN
UPDATE Table_2
SET Col1 = '1'
FROM (SELECT Table_2_ID FROM Table_1)
WHERE Table_1.Table_2_ID = Table_2.ID;
END;
It is needed to change record’s value in the Table_2 AFTER INSERT a record in the Table_1 with the similar ID (Table_2_ID in the Table_1 and ID in the Table_2 are identical).
Col1 in the Table_2 has type VARCHAR2.
I have this code, but after running statement there is an error:
“2/5 PL/SQL: SQL Statement ignored
4/5 PL/SQL: ORA-00933: SQL command not properly ended”
If I got it right, you need such a WHERE clause:
CREATE OR REPLACE TRIGGER Table_2_TRG
AFTER INSERT
ON Table_1
FOR EACH ROW
BEGIN
UPDATE Table_2 b
SET b.Col1 = '1'
WHERE b.id = :new.table_2_id;
END;
this will work:
CREATE OR REPLACE TRIGGER Table_2_TRG
AFTER INSERT
ON Table_1
FOR EACH ROW
BEGIN
UPDATE Table_2
SET Col1 = '1'
where id=:new.id;
END;
I am using the following TRIGGER to Insert in my TEST Table:
create or replace
TRIGGER TRG_CYCLE
BEFORE INSERT ON TEST_CYCLE
FOR EACH ROW
BEGIN
IF :NEW.LOGID IS NULL
THEN SELECT SEQ_CYCLE.nextval INTO :NEW.LOGID from dual;
END IF;
END;
SEQ_CYCLE is the Sequence. Now I have to use the CYCLE option in order to start with 1 after the MAX_VALUE is reached. Since I don't want duplicate LOGIDs I want to do an UPDATE if the LOGID exists, if not an INSERT. Can I do this inside the Trigger?
If I understand well, you may need an INSTEAD OF trigger; to build such a trigger you need to create a VIEW over your table and build the trigger on this view.
For example, say you have:
create sequence SEQ_CYCLE maxValue 3 cycle nocache;
create table TEST_CYCLE ( logId number, someColumn varchar2(20));
You can create a view and a trigger over the view:
create or replace view v_test_cycle as select * from test_cycle;
create or replace trigger trgCycle
instead of insert on v_test_cycle
for each row
declare
vCheck number;
vSeqVal number := SEQ_CYCLE.nextVal;
begin
select count(*)
into vCheck
from v_test_cycle
where logId = vSeqVal;
--
if vCheck = 0 then
insert into test_cycle(logId, someColumn) values ( vSeqVal, :NEW.someColumn);
else
update test_cycle
set someColumn = :NEW.someColumn
where logId = vSeqVal;
end if;
end;
If you do the INSERTs on the view, this is what you get:
SQL> select * from test_cycle;
no rows selected
SQL> insert into v_test_cycle(someColumn) values('some value 1');
1 row created.
SQL> insert into v_test_cycle(someColumn) values('some value 2');
1 row created.
SQL> insert into v_test_cycle(someColumn) values('some value 3');
1 row created.
SQL> insert into v_test_cycle(someColumn) values('some value 4');
1 row created.
SQL> insert into v_test_cycle(someColumn) values('some value 5');
1 row created.
SQL> select * from test_cycle;
LOGID SOMECOLUMN
---------- --------------------
1 some value 4
2 some value 5
3 some value 3
SQL>
I need to execute some statements within the IF clause only if a table exists.
But the issue I am facing is, even when the condition is false, the statements are getting executed.
DECLARE
count_matching_row NUMBER := 0;
count_matching_tbl NUMBER := 0;
BEGIN
SELECT COUNT(*)
INTO count_matching_tbl
FROM user_tables
WHERE LOWER(table_name) = 'tab1';
IF(count_matching_tbl = 1)
THEN
SELECT COUNT (*)
INTO count_matching_row
FROM test1
WHERE ID IN (SELECT ID FROM tab1);
IF(count_matching_row = 0)
THEN
INSERT INTO review_case
SELECT
DISTINCT ID, d,e
FROM tab1
WHERE ID IS NOT NULL;
INSERT INTO review_case_payer
SELECT
a,b,c
FROM tab1
WHERE a IS NOT NULL;
COMMIT;
END IF;
END IF;
END;
/
Whenever I execute these statements, if the table 'tab1' exists it works fine.
If the table tab1 does not exist I get the error
"ORA-06550: line 13, column 14:
PL/SQL: ORA-00942: table or view does not exist"
I get similar errors for each line where I try to access table "tab1"
I tried with ref cursor but still the same, I cannot use it for insert statements.
Your error is due to the fact that you're using a table that may not exist; this error is thrown because the script has compile problems, not data problems, so the way you try to use the IF is not enough to handle your situation.
You need to use some dynamic SQL to handle an object that could not exist; for example, see the following.
If the table does not exist, nothing will be done:
SQL> select * from tab1;
select * from tab1
*
ERROR at line 1:
ORA-00942: table or view does not exist
SQL> declare
2 vCountTab number;
3 begin
4 select count(1)
5 into vCountTab
6 from user_tables
7 where table_name = 'TAB1';
8
9 if vCountTab = 1 then
10 execute immediate 'insert into TAB1 values (1, 2)';
11 end if;
12 end;
13 /
PL/SQL procedure successfully completed.
If the table exists, the insert will be done:
SQL> create table tab1(a number, b number);
Table created.
SQL> declare
2 vCountTab number;
3 begin
4 select count(1)
5 into vCountTab
6 from user_tables
7 where table_name = 'TAB1';
8
9 if vCountTab = 1 then
10 execute immediate 'insert into TAB1 values (1, 2)';
11 end if;
12 end;
13 /
PL/SQL procedure successfully completed.
SQL> select * from tab1;
A B
---------- ----------
1 2
SQL>
I'm attempting to write a trigger that will disallow any room in a hospital to have more than 3 services. The table RoomServices has a room number and a service that it has. So the only way to determine this is to group the rooms by room number and count the services. I have tried the code:
CREATE TRIGGER RoomServiceLimit
BEFORE INSERT OR UPDATE ON RoomServices
FOR EACH ROW
DECLARE
numService NUMBER;
CURSOR C1 IS SELECT count(*) AS RoomCount FROM RoomServices WHERE roomNumber = :new.roomNumber;
BEGIN
IF(inserting) THEN
SELECT count(*) into numService FROM RoomServices WHERE roomNumber = :new.roomNumber;
if(numService > 2) THEN
RAISE_APPLICATION_ERROR(-20001,'Room ' || :new.roomNumber || ' will have more than 3 services.');
END IF;
END IF;
IF(updating) THEN
FOR rec IN C1 LOOP
IF(rec.RoomCount > 2) THEN
RAISE_APPLICATION_ERROR(-20001,'Room ' || :new.roomNumber || ' will have more than 3 services.');
END IF;
END LOOP;
END IF;
END;
/
I've tried running each method separately with insert and update, and inserting always works and updating will always give me the mutating table error. I don't know how else to go about solving this problem, so any advice would be greatly appreciated.
Thanks!
There is no reliable way to enforce this kind of constraint using triggers. One possible approach is to use a materialized view that automatically refreshes on commit and has a check constraint enforcing your business rule:
create table roomservices (
pk number not null primary key,
roomnumber number);
create materialized view mv_roomservices
refresh on commit as
select
pk,
roomnumber,
count(*) over (partition by roomnumber) as cnt
from roomservices;
alter table mv_roomservices add constraint
chk_max_2_services_per_room check (cnt <= 2);
Now, whenever you add more than two services for a room and try to commit your transaction, you will get a ORA-12008 exception (error in materialized view refresh path).
I assume that RoomServices:
a) is a small table that is not intensively modified
b) there will never exist a room with more than 3 services
Note: you say "more than 3 services" but your code says "more than 2 services". So I will use "more than 2 services".
Then, what about using a statement trigger?
CREATE OR REPLACE TRIGGER RoomServiceLimit
AFTER INSERT OR UPDATE ON RoomServices
DECLARE
badRoomsCount NUMBER;
badRoomsList VARCHAR2(32767); -- adjust the varchar2 size according to your requirements
BEGIN
SELECT COUNT(*), LISTAGG(roomNumber, ', ') WITHIN GROUP (ORDER BY 1)
INTO badRoomsCount, badRoomsList
FROM (SELECT roomNumber FROM RoomServices GROUP BY roomNumber HAVING COUNT(*) > 2);
IF (badRoomsCount > 0) THEN
RAISE_APPLICATION_ERROR(-20001,'Room/s '||badRoomsList||' will have more than 2 services.');
END IF;
END;
/
If RoomServices is small but have too many changes (inserts or updates) then you may consider create an index on RoomNumber.
If my assumptions are false try something like:
CREATE GLOBAL TEMPORARY TABLE RoomServicesAux as SELECT roomNumber FROM RoomServices WHERE 1=0;
/
CREATE OR REPLACE TRIGGER PreRoomServiceLimit
BEFORE INSERT OR UPDATE ON RoomServices
BEGIN
DELETE FROM RoomServicesAux;
END;
/
CREATE OR REPLACE TRIGGER RowRoomServiceLimit
BEFORE INSERT OR UPDATE OF roomNumber ON RoomServices FOR EACH ROW
BEGIN
INSERT INTO RoomServicesAux VALUES (:NEW.roomNumber);
END;
/
CREATE OR REPLACE TRIGGER RoomServiceLimit
AFTER INSERT OR UPDATE ON RoomServices
DECLARE
badRoomsCount NUMBER;
badRoomsList VARCHAR2(32767); -- adjust the varchar2 size according to your requirements
BEGIN
SELECT COUNT(*), LISTAGG(roomNumber, ', ') WITHIN GROUP (ORDER BY 1)
INTO badRoomsCount, badRoomsList
FROM (
SELECT roomNumber
FROM RoomServices
WHERE roomNumber in (SELECT roomNumber FROM RoomServicesAux)
GROUP BY roomNumber
HAVING COUNT(*) > 2
);
DELETE FROM RoomServicesAux;
IF (badRoomsCount > 0) THEN
RAISE_APPLICATION_ERROR(-20001,'Room/s '||badRoomsList||' will have more than 2 services.');
END IF;
END;
/
Or if you have Oracle 11g or greater then you can use a compound trigger:
CREATE OR REPLACE TYPE RoomsListType IS TABLE OF INTEGER; -- change to the type of RoomServices.rowNumber
/
CREATE OR REPLACE TRIGGER RoomServiceLimit
FOR INSERT OR UPDATE OF roomNumber ON RoomServices
COMPOUND TRIGGER
RoomsList RoomsListType := RoomsListType();
badRoomsCount NUMBER;
badRoomsList VARCHAR2(32767); -- adjust the varchar2 size according to your requirements
AFTER EACH ROW IS
BEGIN
RoomsList.EXTEND;
RoomsList(RoomsList.COUNT) := :NEW.roomNumber;
END AFTER EACH ROW;
AFTER STATEMENT IS
BEGIN
SELECT COUNT(*), LISTAGG(roomNumber, ', ') WITHIN GROUP (ORDER BY 1)
INTO badRoomsCount, badRoomsList
FROM (
SELECT roomNumber
FROM RoomServices
WHERE roomNumber in (SELECT * FROM table(RoomsList))
GROUP BY roomNumber
HAVING COUNT(*) > 2
);
IF (badRoomsCount > 0) THEN
RAISE_APPLICATION_ERROR(-20001,'Room/s '||badRoomsList||' will have more than 2 services.');
END IF;
END AFTER STATEMENT;
END;
/
Seems you cannot solve this issue without some workarounds. If there is nothing better you can find, check this out:
I guess you have table Room, otherwise create one:
alter table Room add (
servicesCount integer default 0 not null check (servicesCount <= 3)
);
Then update this number with current values (not sure if the statement is valid, it is not the key point here)
update Room r
set servicesCount = (select count(*)
from RoomServices s
where r.roomNumber = s.roomNumber);
then in your trigger
create trigger RoomServiceLimit
before insert or update on RoomServices
for each row
begin
update Room
set servicesCount = servicesCount + 1
where roomNumber = :new.roomNumber;
end;
Looks quite ugly, but, as I've told, I am not sure you can find anything better with trigger.
EDIT
The complete working example
drop table Room;
drop table RoomServices;
create table Room (
roomNumber integer primary key,
servicesCount integer default 0 not null check (servicesCount <= 3)
);
create table RoomServices (
roomNumber integer,
service varchar2(100),
comments varchar2(4000)
);
create trigger RoomServiceLimit
before insert or update or delete on RoomServices
for each row
begin
if inserting then
update Room
set servicesCount = servicesCount + 1
where roomNumber = :new.roomNumber;
elsif updating and :old.roomNumber != :new.roomNumber then
update Room
set servicesCount = servicesCount + 1
where roomNumber = :new.roomNumber;
update Room
set servicesCount = servicesCount - 1
where roomNumber = :old.roomNumber;
elsif deleting then
update Room
set servicesCount = servicesCount - 1
where roomNumber = :old.roomNumber;
end if;
end;
/
insert into Room(roomNumber) values (1);
insert into Room(roomNumber) values (2);
insert into RoomServices(roomNumber,service,comments) values (1,'cleaning','first');
insert into RoomServices(roomNumber,service,comments) values (1,'drying','second');
insert into RoomServices(roomNumber,service,comments) values (1,'watering','third');
insert into RoomServices(roomNumber,service,comments) values (1,'something','third'); -- error
select * from room;
insert into RoomServices(roomNumber,service,comments) values (2,'something','2: first');
update RoomServices
set comments = null
where roomNumber = 2;
select * from room;
update RoomServices -- error
set roomNumber = 1
where roomNumber = 2;
select * from room;
delete from RoomServices where roomNumber = 1;
select * from room;