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
Related
I have this INSERT query, which purpose is to insert the one row in my database.
Similarly I also have a INSERT query which insert multiple rows.
One of the columns in the table is generated after the values has been generated, since it combines a set of column values to construct a name. The name itself it generated from a Trigger, and its triggered After insert, since the column values has to exist for me to generate the name.
my problem now is when I insert one row or multiple rows, I want to know the the generated column value, but when I return it, it states its null?
#$"INSERT INTO registration_table (id, ...,)
VALUES (1,...,)
RETURNING row_id, name;";
which in return gives me an id the one I inserted, but the not actual name but instead I get null..
The trigger is pretty straight forward
CREATE TRIGGER name_insert_trigger
AFTER INSERT
ON registration_table
REFERENCING NEW TABLE AS new_inserts
FOR EACH STATEMENT
WHEN (pg_trigger_depth() = 0)
EXECUTE PROCEDURE registration_entry_name();
CREATE OR REPLACE FUNCTION registration_entry_name()
RETURNS trigger AS
$$
DECLARE
BEGIN
UPDATE registration_table
SET name = |Pattern| -- This one being the actual name generated..
FROM new_inserts
WHERE new_inserts.row_id = registration_table.row_id;
RETURN null;
END;
$$
LANGUAGE plpgsql;
but the insert query above does not return the name?
why not?
You actually need a BEFORE trigger, your data values will be there. The designation of Before and After very often causes misconceptions especially of row level triggers. The terms do not indicate their timing in relation to the DML. I have found it useful to think of them as "before final data values are set" and "after final data values are set" but both run before the invoking DML completes (for now we will bypass deferred triggers). Lets look at inserts. When the before row trigger fires the NEW row contains the values at that point for every column in the row, any value not specified in the statement will be null or contain the specified default if any. Before row triggers can can change any column. After row triggers cannot change columns, if present any change is ignored.
Your description and code imply you need to combine a couple columns to generate the content of another. Since you did not specify exactly that I will build an example and demo.
create table users ( usr_id integer generated always as identity
, lname text not null
, fname text not null
, full_name text not null
) ;
create or replace
function users_bir()
returns trigger
language plpgsql
as $$
begin
if new.full_name is null
then
new.full_name = trim(new.fname) || ' ' || trim(new.lname);
end if;
return new;
end;
$$;
create trigger users_bir_trg
before insert on users
for each row
execute procedure users_bir();
insert into users(fname, lname)
values ( 'George', 'Henery')
, ( 'Samatha', 'van Horm');
insert into users(fname, lname, full_name)
values ( 'Wacky', 'Warriors','Not so tough guys');
This setup allows the full_name to be specified or generated. If only generation is desired remove the IF leaving only the assignment statement. Even better if you have Postgres 12 or higher just define the the column as a generated column. This is also in the demo.
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.
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.
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.
I'm trying to insert 40 rows using an INSERT ALL INTO and I'm not certain on how to insert the surrogate key. Here's what I have
BEGIN
INSERT ALL
INTO question(question_id)
VALUES (question_seq.nextval)
END
Now if I add another INTO VALUES then I get a unique constraint violation.
BEGIN
INSERT ALL
INTO question(question_id)
VALUES (question_seq.nextval)
INTO question(question_id)
VALUES (question_seq.nextval)
END
How can I update the sequences nextval value for each INTO VALUES so that I can avoid the unique constraint violation? I assumed that nextval would automatically update itself.
UPDATE: I don't know if this is the best way to handle this but here's the solution I came up with:
first I created a function that returns a value
then I called that function in the id field of the VALUES clause
create or replace
FUNCTION GET_QUESTION_ID RETURN NUMBER AS
num NUMBER;
BEGIN
SELECT UHCL_QUESTIONS_SEQ.nextval
INTO num
FROM dual;
return num;
END GET_QUESTION_ID;
INSERT ALL
INTO question(question_id)
VALUES (GET_QUESTION_ID())
INTO question(question_id)
VALUES (GET_QUESTION_ID())
Being from a SQL Server background, I've always created a trigger on the table to basically emulate IDENTITY functionality. Once the trigger is on, the SK is automatically generated from the sequence just like identity and you don't have to worry about it.
You can use something like this:
insert into question(question_id)
select question_seq.nextval from
(
select level from dual connect by level <= 40
);
Although it's not a very convenient format, especially if there are other columns you want to add. You'd probably need to create another UNION ALL query, and join it by the LEVEL or ROWNUM.
My first thought was to do something like this:
insert into question(question_id)
select question_seq.nextval value from dual
union all
select question_seq.nextval from dual;
But it generates ORA-02287: sequence number not allowed here, due to the restrictions on sequence values.
By the way, are you sure your INSERT ALL works without a subquery? I get the error ORA-00928: missing SELECT keyword, and the diagram from the 11.2 manual implies there must be a subquery:
I don't know if this is the best way to handle this but here's the solution I came up with:
first I created a function that returns a value
then I called that function in the id field of the VALUES clause
create or replace
FUNCTION GET_QUESTION_ID RETURN NUMBER AS
num NUMBER;
BEGIN
SELECT UHCL_QUESTIONS_SEQ.nextval
INTO num
FROM dual;
return num;
END GET_QUESTION_ID;
INSERT ALL
INTO question(question_id)
VALUES (GET_QUESTION_ID())
INTO question(question_id)
VALUES (GET_QUESTION_ID())