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.
Related
I use Oracle DB V10.2.0.1.0 for my project, along with Java as the server. I am trying to add data into a few tables only through the code, but it requires using the same sequence value.
I have a sequence which represents the T_GROUP table's ID named GROUP_SEQ.
(Increment by: 1, Min_Value: 1, Max_Value: 999999999999999999999999, Cache Size: 20, Cycle: No, Order: No).
Said GROUP_SEQ is incremented by a trigger once I enter a new group into the database:
CREATE OR REPLACE TRIGGER GROUP_TRIGGER2
BEFORE INSERT ON T_GROUP for each row
begin
SELECT GROUP_SEQ.nextval
INTO :new.ID
from dual;
END;
In my code, I performed addGroup() function in my code which successfully adds a new group along with the right GROUP_SEQ value, however when I try to get the currval it fails, because I did not use nextval on it's own, and I get this exception:
ORA-08002: sequence GROUP_SEQ.currval is not yet defined in this session
Even though I did define it in the trigger. Happens the same if I run the same commands through the SQLplus cmd.
Thanks in advance!
Solved it!
The problem was indeed the connection I was using - there was a place where I used getConnection again and thus had a different session.
Thanks #krokodilko
If you have data to insert into multiple tables then write a stored procedure to do the DML for all the tables in one go:
CREATE OR REPLACE PROCEDURE add_group(
in_column_a IN T_GROUP.COLUMN_A%TYPE,
in_column_b IN T_GROUP.COLUMN_B%TYPE,
out_id OUT T_GROUP.ID%TYPE
)
AS
BEGIN
INSERT INTO T_GROUP (
id,
column_a,
column_b
) VALUES (
GROUP_SEQ.NEXTVAL,
in_column_a,
in_column_b
)
RETURNING id INTO out_id;
INSERT INTO other_table (
id
) VALUES (
out_id
);
END;
/
In almost all cases, you do not need to use triggers.
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 table with the following column:
NOTEID NUMBER NOT NULL,
For all intents and purposes, this column is the primary key. This table has a few thousand rows, each with a unique ID. Before, the application would SELECT the MAX() value from the table, add one, then use that as the next value. This is a horrible solution, and is not transaction or thread safe (in fact, before they didn't even have a UNIQUE constraint on the column and I could see the same NOTEID was duplicated in 9 different occasions)..
I'm rather new to Oracle, so I'd like to know the best syntax to ALTER this table and make this column auto-increment instead. If possible, I'd like to make the next value in the sequence be the MAX(NOTEID) + 1 in the table, or just make it 800 or something to start out. Thanks!
You can't alter the table. Oracle doesn't support declarative auto-incrementing columns. You can create a sequence
CREATE SEQUENCE note_seq
START WITH 800
INCREMENT BY 1
CACHE 100;
Then, you can create a trigger
CREATE OR REPLACE TRIGGER populate_note_id
BEFORE INSERT ON note
FOR EACH ROW
BEGIN
:new.note_id := note_seq.nextval;
END;
or, if you want to allow callers to specify a non-default NOTE_ID
CREATE OR REPLACE TRIGGER populate_note_id
BEFORE INSERT ON note
FOR EACH ROW
BEGIN
IF( :new.note_id is null )
THEN
:new.note_id := note_seq.nextval;
END IF;
END;
If your MAX(noteid) is 799, then try:
CREATE SEQUENCE noteseq
START WITH 800
INCREMENT BY 1
Then when inserting a new record, for the NOTEID column, you would do:
noteseq.nextval
I have been looking for a way to define an autoincrement data type in Oracle and have found these questions on Stack Overflow:
Autoincrement in Oracle
Autoincrement Primary key in Oracle database
The way to use autoincrement types consists in defining a sequence and a trigger to make insertion transparent, where the insertion trigger looks so:
create trigger mytable_trg
before insert on mytable
for each row
when (new.id is null)
begin
select myseq.nextval into :new.id from dual;
end;
I have some doubts about the behaviour of this trigger:
What does this trigger do when the supplied value of "id" is different from NULL?
What does the colon before "new" mean?
I want the trigger to insert the new row with the next value of the sequence as ID whatever the supplied value of "new.id" is. I imagine that the WHEN statement makes the trigger to only insert the new row if the supplied ID is NULL (and it will not insert, or will fail, otherwise).
Could I just remove the WHEN statement in order for the trigger to always insert using the next value of the sequence?
The WHEN condition specifies a condition that must be TRUE for the trigger to fire. In this exampple, the trigger will only fire if the new row has a NULL IS. When the ID is not null, the trigger will not fire and so whatever value ID has been given in the insert statement will be left alone.
Yes, if you simply remove the WHEN condition then the trigger will always fire and so will always provide a sequence value for ID.
Nothing. That allows to specify a value manually.
It's a placeholder for the new value of the column.
You have 2 methods you can do:
if the table looks like this:
create table my_test (
id number,
my_test data varchar2(255)
);
and your sequence is this:
create sequence test_seq
start with 1
increment by 1
nomaxvalue;
you can create a trigger like this (with no When statement like Tony Andrews said)
create trigger test_trigger
before insert on my_test
for each row
begin
select test_seq.nextval into :new.id from dual;
end;
or you could just simply use this then you don't need a trigger:
insert into my_test values(test_seq.nextval, 'voila!');
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.