Related
It appears that there is no concept of AUTO_INCREMENT in Oracle, up until and including version 11g.
How can I create a column that behaves like auto increment in Oracle 11g?
There is no such thing as "auto_increment" or "identity" columns in Oracle as of Oracle 11g. However, you can model it easily with a sequence and a trigger:
Table definition:
CREATE TABLE departments (
ID NUMBER(10) NOT NULL,
DESCRIPTION VARCHAR2(50) NOT NULL);
ALTER TABLE departments ADD (
CONSTRAINT dept_pk PRIMARY KEY (ID));
CREATE SEQUENCE dept_seq START WITH 1;
Trigger definition:
CREATE OR REPLACE TRIGGER dept_bir
BEFORE INSERT ON departments
FOR EACH ROW
BEGIN
SELECT dept_seq.NEXTVAL
INTO :new.id
FROM dual;
END;
/
UPDATE:
IDENTITY column is now available on Oracle 12c:
create table t1 (
c1 NUMBER GENERATED by default on null as IDENTITY,
c2 VARCHAR2(10)
);
or specify starting and increment values, also preventing any insert into the identity column (GENERATED ALWAYS) (again, Oracle 12c+ only)
create table t1 (
c1 NUMBER GENERATED ALWAYS as IDENTITY(START with 1 INCREMENT by 1),
c2 VARCHAR2(10)
);
Alternatively, Oracle 12 also allows to use a sequence as a default value:
CREATE SEQUENCE dept_seq START WITH 1;
CREATE TABLE departments (
ID NUMBER(10) DEFAULT dept_seq.nextval NOT NULL,
DESCRIPTION VARCHAR2(50) NOT NULL);
ALTER TABLE departments ADD (
CONSTRAINT dept_pk PRIMARY KEY (ID));
SYS_GUID returns a GUID-- a globally unique ID. A SYS_GUID is a RAW(16). It does not generate an incrementing numeric value.
If you want to create an incrementing numeric key, you'll want to create a sequence.
CREATE SEQUENCE name_of_sequence
START WITH 1
INCREMENT BY 1
CACHE 100;
You would then either use that sequence in your INSERT statement
INSERT INTO name_of_table( primary_key_column, <<other columns>> )
VALUES( name_of_sequence.nextval, <<other values>> );
Or you can define a trigger that automatically populates the primary key value using the sequence
CREATE OR REPLACE TRIGGER trigger_name
BEFORE INSERT ON table_name
FOR EACH ROW
BEGIN
SELECT name_of_sequence.nextval
INTO :new.primary_key_column
FROM dual;
END;
If you are using Oracle 11.1 or later, you can simplify the trigger a bit
CREATE OR REPLACE TRIGGER trigger_name
BEFORE INSERT ON table_name
FOR EACH ROW
BEGIN
:new.primary_key_column := name_of_sequence.nextval;
END;
If you really want to use SYS_GUID
CREATE TABLE table_name (
primary_key_column raw(16) default sys_guid() primary key,
<<other columns>>
)
In Oracle 12c onward you could do something like,
CREATE TABLE MAPS
(
MAP_ID INTEGER GENERATED ALWAYS AS IDENTITY (START WITH 1 INCREMENT BY 1) NOT NULL,
MAP_NAME VARCHAR(24) NOT NULL,
UNIQUE (MAP_ID, MAP_NAME)
);
And in Oracle (Pre 12c).
-- create table
CREATE TABLE MAPS
(
MAP_ID INTEGER NOT NULL ,
MAP_NAME VARCHAR(24) NOT NULL,
UNIQUE (MAP_ID, MAP_NAME)
);
-- create sequence
CREATE SEQUENCE MAPS_SEQ;
-- create tigger using the sequence
CREATE OR REPLACE TRIGGER MAPS_TRG
BEFORE INSERT ON MAPS
FOR EACH ROW
WHEN (new.MAP_ID IS NULL)
BEGIN
SELECT MAPS_SEQ.NEXTVAL
INTO :new.MAP_ID
FROM dual;
END;
/
Here are three flavors:
numeric. Simple increasing numeric value, e.g. 1,2,3,....
GUID. globally univeral identifier, as a RAW datatype.
GUID (string). Same as above, but as a string which might be easier to handle in some languages.
x is the identity column. Substitute FOO with your table name in each of the examples.
-- numerical identity, e.g. 1,2,3...
create table FOO (
x number primary key
);
create sequence FOO_seq;
create or replace trigger FOO_trg
before insert on FOO
for each row
begin
select FOO_seq.nextval into :new.x from dual;
end;
/
-- GUID identity, e.g. 7CFF0C304187716EE040488AA1F9749A
-- use the commented out lines if you prefer RAW over VARCHAR2.
create table FOO (
x varchar(32) primary key -- string version
-- x raw(32) primary key -- raw version
);
create or replace trigger FOO_trg
before insert on FOO
for each row
begin
select cast(sys_guid() as varchar2(32)) into :new.x from dual; -- string version
-- select sys_guid() into :new.x from dual; -- raw version
end;
/
update:
Oracle 12c introduces these two variants that don't depend on triggers:
create table mytable(id number default mysequence.nextval);
create table mytable(id number generated as identity);
The first one uses a sequence in the traditional way; the second manages the value internally.
Oracle Database 12c introduced Identity, an auto-incremental (system-generated) column.
In the previous database versions (until 11g), you usually implement an Identity by creating a Sequence and a Trigger.
From 12c onward, you can create your own Table and define the column that has to be generated as an Identity.
Assuming you mean a column like the SQL Server identity column?
In Oracle, you use a SEQUENCE to achieve the same functionality. I'll see if I can find a good link and post it here.
Update: looks like you found it yourself. Here is the link anyway:
http://www.techonthenet.com/oracle/sequences.php
Trigger and Sequence can be used when you want serialized number that anyone can easily read/remember/understand. But if you don't want to manage ID Column (like emp_id) by this way, and value of this column is not much considerable, you can use SYS_GUID() at Table Creation to get Auto Increment like this.
CREATE TABLE <table_name>
(emp_id RAW(16) DEFAULT SYS_GUID() PRIMARY KEY,
name VARCHAR2(30));
Now your emp_id column will accept "globally unique identifier value".
you can insert value in table by ignoring emp_id column like this.
INSERT INTO <table_name> (name) VALUES ('name value');
So, it will insert unique value to your emp_id Column.
Starting with Oracle 12c there is support for Identity columns in one of two ways:
Sequence + Table - In this solution you still create a sequence as you normally would, then you use the following DDL:
CREATE TABLE MyTable
(ID NUMBER DEFAULT MyTable_Seq.NEXTVAL,
...)
Table Only - In this solution no sequence is explicitly specified. You would use the following DDL:
CREATE TABLE MyTable (ID NUMBER GENERATED AS IDENTITY, ...)
If you use the first way it is backward compatible with the existing way of doing things. The second is a little more straightforward and is more inline with the rest of the RDMS systems out there.
it is called Identity Columns and it is available only from oracle Oracle 12c
CREATE TABLE identity_test_tab
(
id NUMBER GENERATED ALWAYS AS IDENTITY,
description VARCHAR2 (30)
);
example of insert into Identity Columns as below
INSERT INTO identity_test_tab (description) VALUES ('Just DESCRIPTION');
1 row created.
you can NOT do insert like below
INSERT INTO identity_test_tab (id, description) VALUES (NULL, 'ID=NULL and DESCRIPTION');
ERROR at line 1: ORA-32795: cannot insert into a generated always
identity column
INSERT INTO identity_test_tab (id, description) VALUES (999, 'ID=999 and DESCRIPTION');
ERROR at line 1: ORA-32795: cannot insert into a generated always
identity column
useful link
Here is complete solution w.r.t exception/error handling for auto increment, this solution is backward compatible and will work on 11g & 12c, specifically if application is in production.
Please replace 'TABLE_NAME' with your appropriate table name
--checking if table already exisits
BEGIN
EXECUTE IMMEDIATE 'DROP TABLE TABLE_NAME';
EXCEPTION WHEN OTHERS THEN NULL;
END;
/
--creating table
CREATE TABLE TABLE_NAME (
ID NUMBER(10) PRIMARY KEY NOT NULL,
.
.
.
);
--checking if sequence already exists
BEGIN
EXECUTE IMMEDIATE 'DROP SEQUENCE TABLE_NAME_SEQ';
EXCEPTION WHEN OTHERS THEN NULL;
END;
--creating sequence
/
CREATE SEQUENCE TABLE_NAME_SEQ START WITH 1 INCREMENT BY 1 MINVALUE 1 NOMAXVALUE NOCYCLE CACHE 2;
--granting rights as per required user group
/
GRANT SELECT, INSERT, UPDATE, DELETE ON TABLE_NAME TO USER_GROUP;
-- creating trigger
/
CREATE OR REPLACE TRIGGER TABLE_NAME_TS BEFORE INSERT OR UPDATE ON TABLE_NAME FOR EACH ROW
BEGIN
-- auto increment column
SELECT TABLE_NAME_SEQ.NextVal INTO :New.ID FROM dual;
-- You can also put some other required default data as per need of your columns, for example
SELECT SYS_CONTEXT('USERENV', 'SESSIONID') INTO :New.SessionID FROM dual;
SELECT SYS_CONTEXT('USERENV','SERVER_HOST') INTO :New.HostName FROM dual;
SELECT SYS_CONTEXT('USERENV','OS_USER') INTO :New.LoginID FROM dual;
.
.
.
END;
/
Query to create auto increment in oracle. In below query incrmnt column value will be auto incremented wheneever a new row is inserted
CREATE TABLE table1(
id RAW(16) NOT NULL ENABLE,
incrmnt NUMBER(10,0) GENERATED ALWAYS AS IDENTITY
MINVALUE 1 MAXVALUE 999999999999999999999999999 INCREMENT BY 1 START WITH 1 NOORDER NOCYCLE NOT NULL ENABLE,
CONSTRAINT PK_table1 PRIMARY KEY (id) ENABLE);
This is how I did this on an existing table and column (named id):
UPDATE table SET id=ROWNUM;
DECLARE
maxval NUMBER;
BEGIN
SELECT MAX(id) INTO maxval FROM table;
EXECUTE IMMEDIATE 'DROP SEQUENCE table_seq';
EXECUTE IMMEDIATE 'CREATE SEQUENCE table_seq START WITH '|| TO_CHAR(TO_NUMBER(maxval)+1) ||' INCREMENT BY 1 NOMAXVALUE';
END;
CREATE TRIGGER table_trigger
BEFORE INSERT ON table
FOR EACH ROW
BEGIN
:new.id := table_seq.NEXTVAL;
END;
FUNCTION GETUNIQUEID_2 RETURN VARCHAR2
AS
v_curr_id NUMBER;
v_inc NUMBER;
v_next_val NUMBER;
pragma autonomous_transaction;
begin
CREATE SEQUENCE sequnce
START WITH YYMMDD0000000001
INCREMENT BY 1
NOCACHE
select sequence.nextval into v_curr_id from dual;
if(substr(v_curr_id,0,6)= to_char(sysdate,'yymmdd')) then
v_next_val := to_number(to_char(SYSDATE+1, 'yymmdd') || '0000000000');
v_inc := v_next_val - v_curr_id;
execute immediate ' alter sequence sequence increment by ' || v_inc ;
select sequence.nextval into v_curr_id from dual;
execute immediate ' alter sequence sequence increment by 1';
else
dbms_output.put_line('exception : file not found');
end if;
RETURN 'ID'||v_curr_id;
END;
FUNCTION UNIQUE2(
seq IN NUMBER
) RETURN VARCHAR2
AS
i NUMBER := seq;
s VARCHAR2(9);
r NUMBER(2,0);
BEGIN
WHILE i > 0 LOOP
r := MOD( i, 36 );
i := ( i - r ) / 36;
IF ( r < 10 ) THEN
s := TO_CHAR(r) || s;
ELSE
s := CHR( 55 + r ) || s;
END IF;
END LOOP;
RETURN 'ID'||LPAD( s, 14, '0' );
END;
Creating a Sequence:
CREATE SEQUENCE SEQ_CM_LC_FINAL_STATUS
MINVALUE 1 MAXVALUE 999999999999999999999999999
INCREMENT BY 1 START WITH 1 CACHE 20 NOORDER NOCYCLE;
Adding a Trigger
CREATE OR REPLACE TRIGGER CM_LC_FINAL_STATUS_TRIGGER
BEFORE INSERT
ON CM_LC_FINAL_STATUS
FOR EACH ROW
BEGIN
:NEW.LC_FINAL_STATUS_NO := SEQ_CM_LC_FINAL_STATUS.NEXTVAL;
END;
The first step is to create a SEQUENCE in your database, which is a data object that multiple users can access to automatically generate incremented values. As discussed in the documentation, a sequence in Oracle prevents duplicate values from being created simultaneously because multiple users are effectively forced to “take turns” before each sequential item is generated. –
Finally, we’ll create our SEQUENCE that will be utilized later to actually generate the unique, auto incremented value. –
While we have our table created and ready to go, our sequence is thus far just sitting there but never being put to use. This is where TRIGGERS come in. Similar to an event in modern programming languages, a TRIGGER in Oracle is a stored procedure that is executed when a particular event occurs. Typically a TRIGGER will be configured to fire when a table is updated or a record is deleted, providing a bit of cleanup when necessary. –
In our case, we want to execute our TRIGGER prior to INSERT into our CM_LC_FINAL_STATUS table, ensuring our SEQUENCE is incremented and that new value is passed onto our primary key column.
create trigger t1_trigger
before insert on AUDITLOGS
for each row
begin
select t1_seq.nextval into :new.id from dual;
end;
only I have to just change the table name (AUDITLOGS) with your table name and new.id with new.column_name
oracle has sequences AND identity columns in 12c
http://www.oracle-base.com/articles/12c/identity-columns-in-oracle-12cr1.php#identity-columns
I found this but not sure what rdb 7 is
http://www.oracle.com/technetwork/products/rdb/0307-identity-columns-128126.pdf
Maybe just try this simple script:
http://www.hlavaj.sk/ai.php
Result is:
CREATE SEQUENCE TABLE_PK_SEQ;
CREATE OR REPLACE TRIGGER TR_SEQ_TABLE BEFORE INSERT ON TABLE FOR EACH ROW
BEGIN
SELECT TABLE_PK_SEQ.NEXTVAL
INTO :new.PK
FROM dual;
END;
I have a table temp_table with the following columns
Id number,
name varchar,
Password varchar,
pwd_change_date timestamp
I want to capture the timestamp in pwd_change_date column only when password column is changed.
So basically i want to use update statement inside the trigger to update timestamp value in pwd_change_date column for the same record.
Example
When a password is changed for one user, I want to capture the timestamp value in pwd_change_date for the same record.
I tried with before insert and after insert of password on temp_table, but getting mutation error. Is it allowed in Oracle to update the Same row/table on which trigger is fired?
You don't need to update the table again; you can modify the data before it is inserted, with a before-insert row level trigger, e.g.:
create trigger trig_pwd_date
before insert or update on temp_table
for each row
when (old.password is null and new.password is not null or new.password != old.password)
begin
:new.pwd_change_date := systimestamp;
end;
/
db<>fiddle demo
This used the new and old correlation names to decide if the password value has changed; and the new correlation name to assign the system time to the field in the pseudorecord, which becomes the column value when the insert completes.
Hopefully you aren't storing plain-text passwords in your table.
SQL> create table temp_table (password varchar2(50), pwd_change_date TIMESTAMP);
Table created.
SQL> create trigger trig_pwd_date
before insert or update on temp_table
for each row
when (old.password is null and new.password is not null or new.password != old.password)
begin
:new.pwd_change_date := systimestamp;
end; 2 3 4 5 6 7
8 /
Trigger created.
SQL> set time on
15:28:42 SQL> insert into temp_table values ('23456',sysdate);
1 row created.
15:29:01 SQL> commit;
Commit complete.
15:29:09 SQL> select * from temp_table;
PASSWORD
PWD_CHANGE_DATE
12345
21-SEP-20 03.28.02.370377 PM
23456
21-SEP-20 03.29.01.478017 PM
Error code 4098, SQL state 42000: ORA-04098: trigger 'HR.TRGM_ID' is invalid and failed re-validation
I'm getting this problem. What should I do?
create table kids(
id integer primary key,
mbrand varchar(100) ,
mmodel varchar(100),
mprice integer,
mquantity integer,
mdescription varchar(100),
mphoto varchar(100)
);
CREATE SEQUENCE id_seq;
create trigger trgk_id
before insert on kids
for each row
begin
select id_seq.nextval
into :new.id
from dual;
It seems that you shouldn't do anything. Everything works OK, as far as code you posted is concerned (apart from the fact that END is missing).
On the other hand, Oracle complains about trigger whose name is TRGM_ID, while the one whose code we have is named TRGK_ID. Are we talking about the same trigger?
SQL> create table kids(
2 id integer primary key,
3 mbrand varchar(100) ,
4 mmodel varchar(100),
5 mprice integer,
6 mquantity integer,
7 mdescription varchar(100),
8 mphoto varchar(100)
9 );
Table created.
SQL> CREATE SEQUENCE id_seq;
Sequence created.
SQL> create trigger trgk_id
2 before insert on kids
3 for each row
4 begin
5 select id_seq.nextval
6 into :new.id
7 from dual;
8 end;
9 /
Trigger created.
SQL> insert into kids (mbrand) values ('Nike');
1 row created.
SQL> select id, mbrand from kids;
ID MBRAND
---------- ----------
1 Nike
SQL>
The problem is simply that your trigger is missing its END statement. Rewrite the trigger as
create OR REPLACE trigger trgk_id
before insert on kids
for each row
begin
select id_seq.nextval
into :new.id
from dual;
END TRGK_ID; -- added
and you should be good.
dbfiddle here
For Oracle11g no need to use currval and nextval pseudocolumns
within a SQL query statement, rather usable within a PL/SQL
expression.
So, avoid using :
select id_seq.nextval
into :new.id
from dual;
and use directly
:new.id := id_seq.nextval;
instead.
P.S. of course, do the above after fullfilling your main issue of adding an end clause at the end of the trigger.
The error say "TRGM_ID" (with "m"):
Error code 4098, SQL state 42000: ORA-04098: trigger 'HR.TRGM_ID' is invalid and failed re-validation
Your code say "TRGK_ID" (with "k"):
create trigger trgk_id
Check "TRGM_ID" code, or try recompile trigger:
alter trigger [nameOfTrigger] compile;
If you're using Oracle 12c or newer, you could use an identity column instead of manually creating a sequence and trigger. Much cleaner:
create table kids(
id integer generated always as identity primary key,
mbrand varchar(100) ,
mmodel varchar(100),
mprice integer,
mquantity integer,
mdescription varchar(100),
mphoto varchar(100)
);
https://oracle-base.com/articles/12c/identity-columns-in-oracle-12cr1
What i am trying to do
I am trying to rename a column with the following query:
alter table audit_schema rename column object to objectname;.
What is the problem
oracle return this strange error ORA-30512: Cannot modify AHTI.AUDIT_SCHEMA more than once in a transaction after renaming the column.
Table:
Name Null? Type
----------------------------------------- -------- ----------------------------
USERNAME VARCHAR2(30)
CURRENTDATE VARCHAR2(30)
OBJECT VARCHAR2(30)
Trigger:
CREATE OR REPLACE TRIGGER audit_schema_tr
AFTER DDL ON Schema
BEGIN
insert into audit_schema values (user, sysdate,ora_dict_obj_type);
END;
/
You can try disabling the trigger and then renaming the column.
ALTER trigger trigg_name disable
If it doesn't work, drop your trigger -
DROP Trigger trig_name
rename the column and recreate the trigger.
This is only a problem if you're trying to audit changes to your audit table. Another solution to this is to add the following to your trigger. This will prevent having to remember to disable/drop the trigger whenever you are modifying it:
if (NOT (ORA_DICT_OBJ_NAME = 'AUDIT_SCHEMA') AND
ORA_DICT_OBJ_TYPE = 'TABLE')) Then
insert into audit_schema values (user, sysdate,ora_dict_obj_type);
End if;
It appears that there is no concept of AUTO_INCREMENT in Oracle, up until and including version 11g.
How can I create a column that behaves like auto increment in Oracle 11g?
There is no such thing as "auto_increment" or "identity" columns in Oracle as of Oracle 11g. However, you can model it easily with a sequence and a trigger:
Table definition:
CREATE TABLE departments (
ID NUMBER(10) NOT NULL,
DESCRIPTION VARCHAR2(50) NOT NULL);
ALTER TABLE departments ADD (
CONSTRAINT dept_pk PRIMARY KEY (ID));
CREATE SEQUENCE dept_seq START WITH 1;
Trigger definition:
CREATE OR REPLACE TRIGGER dept_bir
BEFORE INSERT ON departments
FOR EACH ROW
BEGIN
SELECT dept_seq.NEXTVAL
INTO :new.id
FROM dual;
END;
/
UPDATE:
IDENTITY column is now available on Oracle 12c:
create table t1 (
c1 NUMBER GENERATED by default on null as IDENTITY,
c2 VARCHAR2(10)
);
or specify starting and increment values, also preventing any insert into the identity column (GENERATED ALWAYS) (again, Oracle 12c+ only)
create table t1 (
c1 NUMBER GENERATED ALWAYS as IDENTITY(START with 1 INCREMENT by 1),
c2 VARCHAR2(10)
);
Alternatively, Oracle 12 also allows to use a sequence as a default value:
CREATE SEQUENCE dept_seq START WITH 1;
CREATE TABLE departments (
ID NUMBER(10) DEFAULT dept_seq.nextval NOT NULL,
DESCRIPTION VARCHAR2(50) NOT NULL);
ALTER TABLE departments ADD (
CONSTRAINT dept_pk PRIMARY KEY (ID));
SYS_GUID returns a GUID-- a globally unique ID. A SYS_GUID is a RAW(16). It does not generate an incrementing numeric value.
If you want to create an incrementing numeric key, you'll want to create a sequence.
CREATE SEQUENCE name_of_sequence
START WITH 1
INCREMENT BY 1
CACHE 100;
You would then either use that sequence in your INSERT statement
INSERT INTO name_of_table( primary_key_column, <<other columns>> )
VALUES( name_of_sequence.nextval, <<other values>> );
Or you can define a trigger that automatically populates the primary key value using the sequence
CREATE OR REPLACE TRIGGER trigger_name
BEFORE INSERT ON table_name
FOR EACH ROW
BEGIN
SELECT name_of_sequence.nextval
INTO :new.primary_key_column
FROM dual;
END;
If you are using Oracle 11.1 or later, you can simplify the trigger a bit
CREATE OR REPLACE TRIGGER trigger_name
BEFORE INSERT ON table_name
FOR EACH ROW
BEGIN
:new.primary_key_column := name_of_sequence.nextval;
END;
If you really want to use SYS_GUID
CREATE TABLE table_name (
primary_key_column raw(16) default sys_guid() primary key,
<<other columns>>
)
In Oracle 12c onward you could do something like,
CREATE TABLE MAPS
(
MAP_ID INTEGER GENERATED ALWAYS AS IDENTITY (START WITH 1 INCREMENT BY 1) NOT NULL,
MAP_NAME VARCHAR(24) NOT NULL,
UNIQUE (MAP_ID, MAP_NAME)
);
And in Oracle (Pre 12c).
-- create table
CREATE TABLE MAPS
(
MAP_ID INTEGER NOT NULL ,
MAP_NAME VARCHAR(24) NOT NULL,
UNIQUE (MAP_ID, MAP_NAME)
);
-- create sequence
CREATE SEQUENCE MAPS_SEQ;
-- create tigger using the sequence
CREATE OR REPLACE TRIGGER MAPS_TRG
BEFORE INSERT ON MAPS
FOR EACH ROW
WHEN (new.MAP_ID IS NULL)
BEGIN
SELECT MAPS_SEQ.NEXTVAL
INTO :new.MAP_ID
FROM dual;
END;
/
Here are three flavors:
numeric. Simple increasing numeric value, e.g. 1,2,3,....
GUID. globally univeral identifier, as a RAW datatype.
GUID (string). Same as above, but as a string which might be easier to handle in some languages.
x is the identity column. Substitute FOO with your table name in each of the examples.
-- numerical identity, e.g. 1,2,3...
create table FOO (
x number primary key
);
create sequence FOO_seq;
create or replace trigger FOO_trg
before insert on FOO
for each row
begin
select FOO_seq.nextval into :new.x from dual;
end;
/
-- GUID identity, e.g. 7CFF0C304187716EE040488AA1F9749A
-- use the commented out lines if you prefer RAW over VARCHAR2.
create table FOO (
x varchar(32) primary key -- string version
-- x raw(32) primary key -- raw version
);
create or replace trigger FOO_trg
before insert on FOO
for each row
begin
select cast(sys_guid() as varchar2(32)) into :new.x from dual; -- string version
-- select sys_guid() into :new.x from dual; -- raw version
end;
/
update:
Oracle 12c introduces these two variants that don't depend on triggers:
create table mytable(id number default mysequence.nextval);
create table mytable(id number generated as identity);
The first one uses a sequence in the traditional way; the second manages the value internally.
Oracle Database 12c introduced Identity, an auto-incremental (system-generated) column.
In the previous database versions (until 11g), you usually implement an Identity by creating a Sequence and a Trigger.
From 12c onward, you can create your own Table and define the column that has to be generated as an Identity.
Assuming you mean a column like the SQL Server identity column?
In Oracle, you use a SEQUENCE to achieve the same functionality. I'll see if I can find a good link and post it here.
Update: looks like you found it yourself. Here is the link anyway:
http://www.techonthenet.com/oracle/sequences.php
Trigger and Sequence can be used when you want serialized number that anyone can easily read/remember/understand. But if you don't want to manage ID Column (like emp_id) by this way, and value of this column is not much considerable, you can use SYS_GUID() at Table Creation to get Auto Increment like this.
CREATE TABLE <table_name>
(emp_id RAW(16) DEFAULT SYS_GUID() PRIMARY KEY,
name VARCHAR2(30));
Now your emp_id column will accept "globally unique identifier value".
you can insert value in table by ignoring emp_id column like this.
INSERT INTO <table_name> (name) VALUES ('name value');
So, it will insert unique value to your emp_id Column.
Starting with Oracle 12c there is support for Identity columns in one of two ways:
Sequence + Table - In this solution you still create a sequence as you normally would, then you use the following DDL:
CREATE TABLE MyTable
(ID NUMBER DEFAULT MyTable_Seq.NEXTVAL,
...)
Table Only - In this solution no sequence is explicitly specified. You would use the following DDL:
CREATE TABLE MyTable (ID NUMBER GENERATED AS IDENTITY, ...)
If you use the first way it is backward compatible with the existing way of doing things. The second is a little more straightforward and is more inline with the rest of the RDMS systems out there.
it is called Identity Columns and it is available only from oracle Oracle 12c
CREATE TABLE identity_test_tab
(
id NUMBER GENERATED ALWAYS AS IDENTITY,
description VARCHAR2 (30)
);
example of insert into Identity Columns as below
INSERT INTO identity_test_tab (description) VALUES ('Just DESCRIPTION');
1 row created.
you can NOT do insert like below
INSERT INTO identity_test_tab (id, description) VALUES (NULL, 'ID=NULL and DESCRIPTION');
ERROR at line 1: ORA-32795: cannot insert into a generated always
identity column
INSERT INTO identity_test_tab (id, description) VALUES (999, 'ID=999 and DESCRIPTION');
ERROR at line 1: ORA-32795: cannot insert into a generated always
identity column
useful link
Here is complete solution w.r.t exception/error handling for auto increment, this solution is backward compatible and will work on 11g & 12c, specifically if application is in production.
Please replace 'TABLE_NAME' with your appropriate table name
--checking if table already exisits
BEGIN
EXECUTE IMMEDIATE 'DROP TABLE TABLE_NAME';
EXCEPTION WHEN OTHERS THEN NULL;
END;
/
--creating table
CREATE TABLE TABLE_NAME (
ID NUMBER(10) PRIMARY KEY NOT NULL,
.
.
.
);
--checking if sequence already exists
BEGIN
EXECUTE IMMEDIATE 'DROP SEQUENCE TABLE_NAME_SEQ';
EXCEPTION WHEN OTHERS THEN NULL;
END;
--creating sequence
/
CREATE SEQUENCE TABLE_NAME_SEQ START WITH 1 INCREMENT BY 1 MINVALUE 1 NOMAXVALUE NOCYCLE CACHE 2;
--granting rights as per required user group
/
GRANT SELECT, INSERT, UPDATE, DELETE ON TABLE_NAME TO USER_GROUP;
-- creating trigger
/
CREATE OR REPLACE TRIGGER TABLE_NAME_TS BEFORE INSERT OR UPDATE ON TABLE_NAME FOR EACH ROW
BEGIN
-- auto increment column
SELECT TABLE_NAME_SEQ.NextVal INTO :New.ID FROM dual;
-- You can also put some other required default data as per need of your columns, for example
SELECT SYS_CONTEXT('USERENV', 'SESSIONID') INTO :New.SessionID FROM dual;
SELECT SYS_CONTEXT('USERENV','SERVER_HOST') INTO :New.HostName FROM dual;
SELECT SYS_CONTEXT('USERENV','OS_USER') INTO :New.LoginID FROM dual;
.
.
.
END;
/
Query to create auto increment in oracle. In below query incrmnt column value will be auto incremented wheneever a new row is inserted
CREATE TABLE table1(
id RAW(16) NOT NULL ENABLE,
incrmnt NUMBER(10,0) GENERATED ALWAYS AS IDENTITY
MINVALUE 1 MAXVALUE 999999999999999999999999999 INCREMENT BY 1 START WITH 1 NOORDER NOCYCLE NOT NULL ENABLE,
CONSTRAINT PK_table1 PRIMARY KEY (id) ENABLE);
This is how I did this on an existing table and column (named id):
UPDATE table SET id=ROWNUM;
DECLARE
maxval NUMBER;
BEGIN
SELECT MAX(id) INTO maxval FROM table;
EXECUTE IMMEDIATE 'DROP SEQUENCE table_seq';
EXECUTE IMMEDIATE 'CREATE SEQUENCE table_seq START WITH '|| TO_CHAR(TO_NUMBER(maxval)+1) ||' INCREMENT BY 1 NOMAXVALUE';
END;
CREATE TRIGGER table_trigger
BEFORE INSERT ON table
FOR EACH ROW
BEGIN
:new.id := table_seq.NEXTVAL;
END;
FUNCTION GETUNIQUEID_2 RETURN VARCHAR2
AS
v_curr_id NUMBER;
v_inc NUMBER;
v_next_val NUMBER;
pragma autonomous_transaction;
begin
CREATE SEQUENCE sequnce
START WITH YYMMDD0000000001
INCREMENT BY 1
NOCACHE
select sequence.nextval into v_curr_id from dual;
if(substr(v_curr_id,0,6)= to_char(sysdate,'yymmdd')) then
v_next_val := to_number(to_char(SYSDATE+1, 'yymmdd') || '0000000000');
v_inc := v_next_val - v_curr_id;
execute immediate ' alter sequence sequence increment by ' || v_inc ;
select sequence.nextval into v_curr_id from dual;
execute immediate ' alter sequence sequence increment by 1';
else
dbms_output.put_line('exception : file not found');
end if;
RETURN 'ID'||v_curr_id;
END;
FUNCTION UNIQUE2(
seq IN NUMBER
) RETURN VARCHAR2
AS
i NUMBER := seq;
s VARCHAR2(9);
r NUMBER(2,0);
BEGIN
WHILE i > 0 LOOP
r := MOD( i, 36 );
i := ( i - r ) / 36;
IF ( r < 10 ) THEN
s := TO_CHAR(r) || s;
ELSE
s := CHR( 55 + r ) || s;
END IF;
END LOOP;
RETURN 'ID'||LPAD( s, 14, '0' );
END;
Creating a Sequence:
CREATE SEQUENCE SEQ_CM_LC_FINAL_STATUS
MINVALUE 1 MAXVALUE 999999999999999999999999999
INCREMENT BY 1 START WITH 1 CACHE 20 NOORDER NOCYCLE;
Adding a Trigger
CREATE OR REPLACE TRIGGER CM_LC_FINAL_STATUS_TRIGGER
BEFORE INSERT
ON CM_LC_FINAL_STATUS
FOR EACH ROW
BEGIN
:NEW.LC_FINAL_STATUS_NO := SEQ_CM_LC_FINAL_STATUS.NEXTVAL;
END;
The first step is to create a SEQUENCE in your database, which is a data object that multiple users can access to automatically generate incremented values. As discussed in the documentation, a sequence in Oracle prevents duplicate values from being created simultaneously because multiple users are effectively forced to “take turns” before each sequential item is generated. –
Finally, we’ll create our SEQUENCE that will be utilized later to actually generate the unique, auto incremented value. –
While we have our table created and ready to go, our sequence is thus far just sitting there but never being put to use. This is where TRIGGERS come in. Similar to an event in modern programming languages, a TRIGGER in Oracle is a stored procedure that is executed when a particular event occurs. Typically a TRIGGER will be configured to fire when a table is updated or a record is deleted, providing a bit of cleanup when necessary. –
In our case, we want to execute our TRIGGER prior to INSERT into our CM_LC_FINAL_STATUS table, ensuring our SEQUENCE is incremented and that new value is passed onto our primary key column.
create trigger t1_trigger
before insert on AUDITLOGS
for each row
begin
select t1_seq.nextval into :new.id from dual;
end;
only I have to just change the table name (AUDITLOGS) with your table name and new.id with new.column_name
oracle has sequences AND identity columns in 12c
http://www.oracle-base.com/articles/12c/identity-columns-in-oracle-12cr1.php#identity-columns
I found this but not sure what rdb 7 is
http://www.oracle.com/technetwork/products/rdb/0307-identity-columns-128126.pdf
Maybe just try this simple script:
http://www.hlavaj.sk/ai.php
Result is:
CREATE SEQUENCE TABLE_PK_SEQ;
CREATE OR REPLACE TRIGGER TR_SEQ_TABLE BEFORE INSERT ON TABLE FOR EACH ROW
BEGIN
SELECT TABLE_PK_SEQ.NEXTVAL
INTO :new.PK
FROM dual;
END;