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.
Related
I am creating a function that will create a new table and insert informations about that table into other tables.
To create that table I am using the
CREATE TABLE IF NOT EXISTS
statement. Sadly it does not update the FOUND special variable in PostgreSQL nor can i find any other variable that would be updated.
Is there any way in PL/PGSQL to know whether that statement created a table or not?
The target of it is to not to double the informations in the other tables.
You may use CREATE TABLE AS in combination with ON_ERROR_ROLLBACK:
BEGIN;
-- Do inital stuff
\set ON_ERROR_ROLLBACK on
CREATE TABLE my_table AS
SELECT id, name FROM (VALUES (1, 'Bob'), (2, 'Mary')) v(id, name);
\set ON_ERROR_ROLLBACK off
-- Do remaining stuff
END;
To put it bluntly, with \set ON_ERROR_ROLLBACK on postgres will create a savepoint before each statement and automatically rollback to this savepoint or releasing it depending on the success of that statement.
The code above will execute initial and remaining stuff even if the table creation fails.
No, there are not any information if this command created table or not. The found variable is updated after query execution - not after DDL command. There is guaranteed so after this command, the table will be or this command fails to an exception.
All i want is to select all rows from a table and once it is selected and displayed, the data residing in table must get completely deleted. The main concern is that this must be done using sql only and not plsql. Is there a way we can do this inside a package and call that package in a select statement? Please enlighten me here.
Dummy Table is as follows:
ID NAME SALARY DEPT
==================================
1 Sam 50000 HR
2 Max 45000 SALES
3 Lex 51000 HR
4 Nate 66000 DEV
Any help would be greatly appreciated.
select * from Table_Name;
Delete from Table_Name
To select the data from a SQL query try using a pipelined function.
The function can define a cursor for the data you want (or all the data in the table), loop through the cursor piping each row as it goes.
When the cursor loop ends, i.e. all data has been consumed by your query, the function can perform a TRUNCATE table.
To select from the function use the following syntax;
SELECT *
FROM TABLE(my_function)
See the following Oracle documentation for information pipelined functions - https://docs.oracle.com/cd/B28359_01/appdev.111/b28425/pipe_paral_tbl.htm
This cannot be done inside a package, because " this must be done using sql only and not plsql". A package is PL/SQL.
However it is very simple. You want two things: select the table data and delete it. Two things, two commands.
select * from mytable;
truncate mytable;
(You could replace truncate mytable; with delete from mytable;, but this is slower and needs to be followed by commit; to confirm the deletion and end the transaction.)
Without pl/sql it's not possible.
Using pl/sql you can create a function which will populate a row, and then delete
Here is example :
drop table tempdate;
create table tempdate as
select '1' id from dual
UNION
select '2' id from dual
CREATE TYPE t_tf_row AS OBJECT (
id NUMBER
);
CREATE TYPE t_tf_tab IS TABLE OF t_tf_row;
CREATE OR REPLACE FUNCTION get_tab_tf RETURN t_tf_tab PIPELINED AS
PRAGMA AUTONOMOUS_TRANSACTION;
BEGIN
FOR rec in (select * from tempdate) LOOP
PIPE ROW(t_tf_row(rec.id));
END LOOP;
delete from tempdate ; commit;
END;
select * from table(get_tab_tf) -- it will populate and then delete
select * from tempdate --you can check here result of deleting
you can use below query
select * from Table_demo delete from Table_demo
The feature you seek is SERIALIZABLE ISOLATION LEVEL. This feature enables repeatable reads, which in particular guarantee that both SELECTand DELETEwill read and process the same identical data.
Example
Alter session set isolation_level=serializable;
select * from tempdate;
--- now insert from other session a new record
delete from tempdate ;
commit;
-- re-query the table old records are deleted, new recor preserved.
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.
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())