How can i make multiple, composite query in oracle?
for example this several queries in one step?
1
CREATE TABLE test (id NUMBER PRIMARY KEY, name VARCHAR2(30));
2
CREATE SEQUENCE test_sequence START WITH 1 INCREMENT BY 1;
3
CREATE OR REPLACE TRIGGER test_trigger
BEFORE INSERT
ON test
REFERENCING NEW AS NEW
FOR EACH ROW
BEGIN
SELECT test_sequence.nextval INTO :NEW.ID FROM dual;
END;
4
INSERT INTO test (name) VALUES ('Jon');
5
INSERT INTO test (name) VALUES ('Meloun');
We solved it by wrapping each statement in an EXECUTE IMMEDIATE command inside a PL/SQL script:
BEGIN
EXECUTE IMMEDIATE 'CREATE TABLE test (id NUMBER PRIMARY KEY, name VARCHAR2(30))';
EXECUTE IMMEDIATE 'CREATE SEQUENCE test_sequence START WITH 1 INCREMENT BY 1';
-- etc
END;
By and large DDL statements have to executed one at a time. It is true that Oracle supports the CREATE SCHEMA syntax, but this only permits the creation of multiple tables and/or views plus grants on them. It doesn't include ancilliary objects such as sequences or triggers.
You could turn the two inserts into a single statement like this:
INSERT INTO test (name)
select 'Jon' from dual
union all
select 'Meloun' from dual
/
This might be more trouble than its worth, but I suppose it does give you a simple transactionality: it inserts either all the rows or none of them.
Related
I have a table and I want to increment a column by 1 when I insert a row into the same table.
Table users - when I insert first row value of idusers is 1, and in second row value is 2 ....
This is the table
USERS
EMAIL primary key
USERNAME
PASSWORD
IDUSER and this the column I want to be AUTO_INCREMENT
I have tried this code
CREATE SEQUENCE seq_person
MINVALUE 1
START WITH 1
INCREMENT BY 1
CACHE 10;
create or replace trigger incrementIdUser
before insert on users
for each row
begin
select seq_person.nextval into :new.IDUSER from users;
end;
But I get an error when I insert a row:
Erreur lors de l'enregistrement des modifications de la table "SOCIAL"."USERS" :
Ligne 1 : ORA-01403: no data found
ORA-01403: no data found
ORA-06512: at "SOCIAL.INCREMENTIDUSER", line 2
ORA-04088: error during execution of trigger 'SOCIAL.INCREMENTIDUSER'
ORA-06512: at line 1
Not like that, but
create or replace trigger incrementIdUser
before insert on users
for each row
begin
:new.iduser := seq_person.nextval;
end;
Code you wrote selects from users table (which is empty, hence NO_DATA_FOUND). If it contained more than a single row, you'd get TOO_MANY_ROWS (as you're selecting into a scalar variable (:new.iduser). Finally, there's danger of mutating table error as you can't select from a table which is just being modified (in this trigger type).
Insetead of select seq_person.nextval into :new.IDUSER from users; to assign sequence value into iduser you need to use :new.IDUSER :=seq_person.nextval;
create or replace trigger incrementIdUser
before insert on users
for each row
begin
:new.IDUSER :=seq_person.nextval;
end;
You get that error because there are zero rows in the USERS table so SELECT ... FROM USERS returns no rows.
What you want is to either use a table that will always return a single row (which, in Oracle, is the DUAL table):
create or replace trigger incrementIdUser
before insert on users
for each row
begin
select seq_person.nextval into :new.IDUSER from DUAL;
end;
Or, the better solution, is to not use an SQL statement and use pure PL/SQL:
create or replace trigger incrementIdUser
before insert on users
for each row
begin
:new.IDUSER := seq_person.nextval;
end;
Instead of using a trigger, you should use an identity column in the create table statement:
create table users
(iduser integer generated by default on null as identity (nomaxvalue nocache order),
...);
I have an oracle table which has
An auto increment primary key which uses a sequence.
Unique key
Non unique field/s
create table FOO (
ai_id number primary key,
name varchar(20),
bar varchar(20)
CONSTRAINT foo_uk_name UNIQUE (name)
);
create sequence FOO_seq;
create or replace trigger FOO_trg
before insert on FOO
for each row
begin
select FOO_seq.nextval into :new.ai_id from dual;
end;
I have separate stored procedure which upserts the table
create PROCEDURE UPSERT_FOO(
name_input IN VARCHAR2,
bar_input IN VARCHAR2
begin
begin
insert into FOO ( name, bar )
values ( name_input, bar_input )
exception
when dup_val_on_index then
update FOO
set bar = bar_input
where name = name_input
end;
end;
This works perfectly fine but the only issue is, sequence "FOO_seq" always increases regardless of whether it is an update or insert(As FOO_seq increments in "FOO_trg" before it inserts).
Is there a way to increment the sequence, only when there is an insert, without hurting the performance?
Oracle has a built-in merge statement to do an 'upsert':
create PROCEDURE UPSERT_FOO(
name_input IN VARCHAR2,
bar_input IN VARCHAR2
) as
begin
merge into foo
using (
select name_input as name, bar_input as bar from dual
) src
on (foo.name = src.name)
when matched then
update set foo.bar = src.bar
when not matched then
insert (name, bar)
values (src.name, src.bar);
end;
/
The insert only happens (and thus the trigger only fires, incrementing the sequence) if there is no match.
That doesn't have to be done through a procedure now, of course; you could just issue a merge directly, plugging in the name/bar values you would currently have to pass to the procedure.
Incidentally, your trigger could be simplified slightly to do an assignment:
create or replace trigger FOO_trg
before insert on FOO
for each row
begin
:new.ai_id := FOO_seq.nextval;
end;
/
db<>fiddles using your original code and using the code above. Notice the ID for 'b' in the final query; 5 in the first one, but only 2 in the second one.
Gaps in sequences shouldn't matter, of course; they are guaranteed to increment and be unique (if they don't cycle), not to be gapless. Or to necessarily be issued in strict order if you have a cache and are using RAC. Still, your approach would potentially waste a lot of values for no reason, and it doesn't need to be that complicated.
Since Oracle 12c we can use IDENTITY fields.
Is there a way to retrieve the last inserted identity (i.e. select ##identity or select LAST_INSERTED_ID() and so on)?
Well. Oracle uses sequences and default values for IDENTITY functionality in 12c. Therefore you need to know about sequences for your question.
First create a test identity table.
CREATE TABLE IDENTITY_TEST_TABLE
(
ID NUMBER GENERATED ALWAYS AS IDENTITY
, NAME VARCHAR2(30 BYTE)
);
First, lets find your sequence name that is created with this identity column. This sequence name is a default value in your table.
Select TABLE_NAME, COLUMN_NAME, DATA_DEFAULT from USER_TAB_COLUMNS
where TABLE_NAME = 'IDENTITY_TEST_TABLE';
for me this value is "ISEQ$$_193606"
insert some values.
INSERT INTO IDENTITY_TEST_TABLE (name) VALUES ('atilla');
INSERT INTO IDENTITY_TEST_TABLE (name) VALUES ('aydın');
then insert value and find identity.
INSERT INTO IDENTITY_TEST_TABLE (name) VALUES ('atilla');
SELECT "ISEQ$$_193606".currval from dual;
you should see your identity value. If you want to do in one block use
declare
s2 number;
begin
INSERT INTO IDENTITY_TEST_TABLE (name) VALUES ('atilla') returning ID into s2;
dbms_output.put_line(s2);
end;
Last ID is my identity column name.
Please check
INSERT INTO yourtable (....)
VALUES (...)
RETURNING pk_id INTO yourtable;
It will help you to retrieve last inserted row
It seems that Oracle implemented IDENTITY just to say that they support identities. Everything is still implemented using SEQUENCES and sometimes you need to access the SEQUENCE to make some of the work (i.e. retrieve the latest inserted IDENTITY).
There is not a way to retrieve the IDENTITY similar to MySQL, SQL Server, DB2, and so on, you have to retrieve it using the SEQUENCE.
IDENTITY column uses a SEQUENCE “under the hood” - creating and dropping sequence automatically with the table it uses.
Also, you can specify start with and increment parameters using
start with 1000 and increment by 2. It's really very convenient to use IDENTITY when you don't want to operate it's values directly.
But if you need to somehow operate sequence directly you should use
another option available in Oracle 12c - column default values. Sutch default
values could be generated from sequence nextval or currval. To allow you to have a comprehensible sequence name and use it as "identity" without a trigger.
create table my_new_table
(id number default my_new_table_seq.nextval not null)
You will be always able to call: my_new_table_seq.currval.
It is possible to get ID generated from SEQUENCE on insert statement using RETURNING clause.
For example, create a temporary table:
create global temporary table local_identity_storage ("id" number) on commit delete rows
Make some insert saving this value in the temporary table:
CREATE TABLE identity_test_table (
id_ident NUMBER GENERATED BY DEFAULT AS IDENTITY,
same_value VARCHAR2(100)
);
declare
v_id number(10, 0);
begin
INSERT INTO identity_test_table
(same_value)
VALUES
('Test value')
RETURNING id_ident INTO v_id;
insert into local_identity_storage ("id") values (v_id);
commit;
end;
Now you have "local" inserted id.
select "id" from local_identity_storage
As I've written in this blog post, you could fetch all the current identity values of your schema with a single query:
with
function current_value(p_table_name varchar2) return number is
v_current number;
begin
for rec in (
select sequence_name
from user_tab_identity_cols
where table_name = p_table_name
)
loop
execute immediate 'select ' || rec.sequence_name || '.currval from dual'
into v_current;
return v_current;
end loop;
return null;
end;
select *
from (
select table_name, current_value(table_name) current_value
from user_tables
)
where current_value is not null
order by table_name;
/
What is your scope, global or last user inserted?
If global just use
SELECT mytable_seq.nextval MyTableID FROM DUAL
https://www.sitepoint.com/community/t/oracle-last-insert-id-question/1402
If specific encapsulate your inserts & query within a transaction.
the last insert will be the highest value of the column.
so I think that the easiest way to do it is with the max() method.
something like this
select max(id) from table_name
I have a workqueue table that has a workid column. The workID column has values that increment automatically. Is there a way I can run a query in the backend to insert a new row and have the workID column increment automatically?
When I try to insert a null, it throws error ORA01400 - Cannot insert null into workid.
insert into WORKQUEUE (facilitycode,workaction,description) values ('J', 'II', 'TESTVALUES')
What I have tried so far - I tried to look at the table details and didn't see any auto-increment. The table script is as follow
"WORKID" NUMBER NOT NULL ENABLE,
Database: Oracle 10g
Screenshot of some existing data.
ANSWER:
I have to thank each and everyone for the help. Today was a great learning experience and without your support, I couldn't have done. Bottom line is, I was trying to insert a row into a table that already has sequences and triggers. All I had to do was find the right sequence, for my question, and call that sequence into my query.
The links you all provided me helped me look these sequences up and find the one that is for this workid column. Thanks to you all, I gave everyone a thumbs up, I am able to tackle another dragon today and help patient care take a step forward!"
This is a simple way to do it without any triggers or sequences:
insert into WORKQUEUE (ID, facilitycode, workaction, description)
values ((select max(ID)+1 from WORKQUEUE), 'J', 'II', 'TESTVALUES')
It worked for me but would not work with an empty table, I guess.
To get an auto increment number you need to use a sequence in Oracle.
(See here and here).
CREATE SEQUENCE my_seq;
SELECT my_seq.NEXTVAL FROM DUAL; -- to get the next value
-- use in a trigger for your table demo
CREATE OR REPLACE TRIGGER demo_increment
BEFORE INSERT ON demo
FOR EACH ROW
BEGIN
SELECT my_seq.NEXTVAL
INTO :new.id
FROM dual;
END;
/
There is no built-in auto_increment in Oracle.
You need to use sequences and triggers.
Read here how to do it right. (Step-by-step how-to for "Creating auto-increment columns in Oracle")
ELXAN#DB1> create table cedvel(id integer,ad varchar2(15));
Table created.
ELXAN#DB1> alter table cedvel add constraint pk_ad primary key(id);
Table altered.
ELXAN#DB1> create sequence test_seq start with 1 increment by 1;
Sequence created.
ELXAN#DB1> create or replace trigger ad_insert
before insert on cedvel
REFERENCING NEW AS NEW OLD AS OLD
for each row
begin
select test_seq.nextval into :new.id from dual;
end;
/ 2 3 4 5 6 7 8
Trigger created.
ELXAN#DB1> insert into cedvel (ad) values ('nese');
1 row created.
You can use either SEQUENCE or TRIGGER to increment automatically the value of a given column in your database table however the use of TRIGGERS would be more appropriate. See the following documentation of Oracle that contains major clauses used with triggers with suitable examples.
Use the CREATE TRIGGER statement to create and enable a database trigger, which is:
A stored PL/SQL block associated with a table, a schema, or the
database or
An anonymous PL/SQL block or a call to a procedure implemented in
PL/SQL or Java
Oracle Database automatically executes a trigger when specified conditions occur. See.
Following is a simple TRIGGER just as an example for you that inserts the primary key value in a specified table based on the maximum value of that column. You can modify the schema name, table name etc and use it. Just give it a try.
/*Create a database trigger that generates automatically primary key values on the CITY table using the max function.*/
CREATE OR REPLACE TRIGGER PROJECT.PK_MAX_TRIGGER_CITY
BEFORE INSERT ON PROJECT.CITY
FOR EACH ROW
DECLARE
CNT NUMBER;
PKV CITY.CITY_ID%TYPE;
NO NUMBER;
BEGIN
SELECT COUNT(*)INTO CNT FROM CITY;
IF CNT=0 THEN
PKV:='CT0001';
ELSE
SELECT 'CT'||LPAD(MAX(TO_NUMBER(SUBSTR(CITY_ID,3,LENGTH(CITY_ID)))+1),4,'0') INTO PKV
FROM CITY;
END IF;
:NEW.CITY_ID:=PKV;
END;
Would automatically generates values such as CT0001, CT0002, CT0002 and so on and inserts into the given column of the specified table.
SQL trigger for automatic date generation in oracle table:
CREATE OR REPLACE TRIGGER name_of_trigger
BEFORE INSERT
ON table_name
REFERENCING NEW AS NEW
FOR EACH ROW
BEGIN
SELECT sysdate INTO :NEW.column_name FROM dual;
END;
/
the complete know how, i have included a example of the triggers and sequence
create table temasforo(
idtemasforo NUMBER(5) PRIMARY KEY,
autor VARCHAR2(50) NOT NULL,
fecha DATE DEFAULT (sysdate),
asunto LONG );
create sequence temasforo_seq
start with 1
increment by 1
nomaxvalue;
create or replace
trigger temasforo_trigger
before insert on temasforo
referencing OLD as old NEW as new
for each row
begin
:new.idtemasforo:=temasforo_seq.nextval;
end;
reference:
http://thenullpointerexceptionx.blogspot.mx/2013/06/llaves-primarias-auto-incrementales-en.html
For completeness, I'll mention that Oracle 12c does support this feature. Also it's supposedly faster than the triggers approach. For example:
CREATE TABLE foo
(
id NUMBER GENERATED BY DEFAULT AS IDENTITY (
START WITH 1 NOCACHE ORDER ) NOT NULL ,
name VARCHAR2 (50)
)
LOGGING ;
ALTER TABLE foo ADD CONSTRAINT foo_PK PRIMARY KEY ( id ) ;
Best approach: Get the next value from sequence
The nicest approach is getting the NEXTVAL from the SEQUENCE "associated" with the table. Since the sequence is not directly associated to any specific table,
we will need to manually refer the corresponding table from the sequence name convention.
The sequence name used on a table, if follow the sequence naming convention, will mention the table name inside its name. Something likes <table_name>_SEQ. You will immediately recognize it the moment you see it.
First, check within Oracle system if there is any sequence "associated" to the table
SELECT * FROM all_sequences
WHERE SEQUENCE_OWNER = '<schema_name>';
will present something like this
Grab that SEQUENCE_NAME and evaluate the NEXTVAL of it in your INSERT query
INSERT INTO workqueue(id, value) VALUES (workqueue_seq.NEXTVAL, 'A new value...')
Additional tip
In case you're unsure if this sequence is actually associated with the table, just quickly compare the LAST_NUMBER of the sequence (meaning the current value) with the maximum id of
that table. It's expected that the LAST_NUMBER is greater than or equals to the current maximum id value in the table, as long as the gap is not too suspiciously large.
SELECT LAST_NUMBER
FROM all_sequences
WHERE SEQUENCE_OWNER = '<schema_name>' AND SEQUENCE_NAME = 'workqueue_seq';
SELECT MAX(ID)
FROM workqueue;
Reference: Oracle CURRVAL and NEXTVAL
Alternative approach: Get the current max id from the table
The alternative approach is getting the max value from the table, please refer to Zsolt Sky answer in this same question
This is a simple way to do it without any triggers or sequences:
insert into WORKQUEUE (ID, facilitycode, workaction, description)
values ((select count(1)+1 from WORKQUEUE), 'J', 'II', 'TESTVALUES');
Note : here need to use count(1) in place of max(id) column
It perfectly works for an empty table also.
This is what I currently have:
CREATE OR REPLACE TRIGGER MYTRIGGER
AFTER INSERT ON SOMETABLE
FOR EACH ROW
DECLARE
v_emplid varchar2(10);
BEGIN
SELECT
personnum into v_emplid
FROM PERSON
WHERE PERSONID = :new.EMPLOYEEID;
dbms_output.put(v_emplid);
/* INSERT INTO SOMEOTHERTABLE USING v_emplid and some of the other values from the trigger table*/
END MYTRIGGER;
DBA_ERRORS has this error:
PL/SQL: ORA-00923: FROM keyword not found where expected
1) There must be something else to your example because that sure seems to work for me
SQL> create table someTable( employeeid number );
Table created.
SQL> create table person( personid number, personnum varchar2(10) );
Table created.
SQL> ed
Wrote file afiedt.buf
1 CREATE OR REPLACE TRIGGER MYTRIGGER
2 AFTER INSERT ON SOMETABLE
3 FOR EACH ROW
4 DECLARE
5 v_emplid varchar2(10);
6 BEGIN
7 SELECT personnum
8 into v_emplid
9 FROM PERSON
10 WHERE PERSONID = :new.EMPLOYEEID;
11 dbms_output.put(v_emplid);
12 /* INSERT INTO SOMEOTHERTABLE USING v_emplid and some of the other values
from the trigger table*/
13* END MYTRIGGER;
14 /
Trigger created.
SQL> insert into person values( 1, '123' );
1 row created.
SQL> insert into sometable values( 1 );
1 row created.
2) You probably want to declare V_EMPLID as being of type Person.PersonNum%TYPE so that you can be certain that the data type is correct and so that if the data type of the table changes you won't need to change your code.
3) I assume that you know that your trigger cannot query or update the table on which the trigger is defined (so no queries or inserts into someTable).
You are playing with Lava (not just fire) in your trigger. DBMS_OUTPUT in a trigger is really, really bad. You can blow-out on a buffer overflow in your trigger and the whole transaction is shot. Good luck tracking that down. If you must do output-to-console like behavior, invoke an AUTONOMOUS TRANSACTION procedure that writes to a table.
Triggers are pretty evil. I used to like them, but they are too hard to remember about. They affect data often times leading to MUTATING data (scary and not just because Halloween is close).
We use triggers to change the value of columns like .new:LAST_MODIFIED := sysdate and .new:LAST_MODIFIED_BY := user. That's it.
Don't ever allow a TRIGGER to prevent a transaction from completing. Find another option.
I would not use a select statment in a trigger ever. Insert into the table rather than a select into. Once the table already exists select into does not work in most databases.