How to create id with AUTO_INCREMENT on Oracle?

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:

1. numeric. Simple increasing numeric value, e.g. 1,2,3,....
2. GUID. globally univeral identifier, as a RAW datatype.
3. 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.

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

Starting with Oracle 12c there is support for Identity columns in one of two ways:

1. 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, ...)

2. 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.

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.

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

 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

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;