Using Oracle, I have a procedure to create unique ID numbers. Currently the ID number is built with the sysdate year concatenated with a "-". I then update the ID number to concatenate a value from within the table after the dash.
EX: 2022-8501.
Instead of using a table value, I want to increment the number after the dash by 1, and it should start back at 1 every year.
EX: 2022-1, 2022-2, 2022-3 // (Next year) 2023-1, 2023-2, 2023-3
What would be the best way to approach this? I have attached my current code below.
INSERT INTO PLANE_INFO.ID_NUMBERS (PLANE_ID)
VALUES (TO_CHAR(SYSDATE, 'YYYY')||'-')
RETURNING ENTRY_ID INTO v_entry_id;
UPDATE PLANE_INFO.ID_NUMBERS
SET PLANE_ID = PLANE_ID || LPAD(v_entry_id,5,'0')
WHERE ENTRY_ID = v_entry_id;
The "best" way? Use a sequence.
create sequence seq;
insert into plane_info.id_numbers (plane_id)
values (extract (year from sysdate) ||'-'|| seq.nextval);
[TL;DR] Just use a normal sequence and if you want to generate the pseudo-sequence that restarts every year then you can calculate it for display purposes (but you should not use it as a referential constraint).
If you have the table:
CREATE TABLE PLANE_INFO.ID_NUMBERS (
id NUMBER
GENERATED ALWAYS AS IDENTITY
CONSTRAINT table_name__id__pk PRIMARY KEY,
year NUMBER(4)
CONSTRAINT table_name__year__nn NOT NULL
);
Note: IDENTITY columns are available from Oracle 12.
Then you have an incrementing sequence (that you can use as the primary key and for any referential constraints) and a year column.
You can generate your pseudo-sequence (for display purposes, rather than as a referential constraint) using the ROW_NUMBER() analytic function and string concatenation:
SELECT t.*,
YEAR
|| '-'
|| LPAD(ROW_NUMBER() OVER (PARTITION BY YEAR ORDER BY id), 5, '0')
AS pseudo_seq
FROM PLANE_INFO.ID_NUMBERS t
db<>fiddle here
Related
Below the simplified structure of a table:
create table customer(
incident_id number,
customer_id number,
customer_name varchar2(400),
sla_id number
failure_start_date date,
failure_end_date date,
churn_flag number, -- 0 or 1
active number, -- 0 or 1
constraint pk_incident_id primary key (incident_id))
PARTITION BY LIST (active)
SUBPARTITION BY LIST (churn_flag)
SUBPARTITION TEMPLATE
( SUBPARTITION sp_churn_flag_1 VALUES (1)
, SUBPARTITION sp_churn_flag_0 VALUES (0)
)
(PARTITION sp_active_1 values (1)
, PARTITION sp_active_0 VALUES (0)
)
,
ENABLE ROW MOVEMENT COMPRESS FOR QUERY LOW;
Now I need to add additonally to the existing Composite-List-Partition an Interval-Range-Partitioning, in order to partitionate the data by month (failure_starte_date - YYYYMM). The table contains data from 200701 up to now (201511). Failure_start_date < 2013 should be partitionied into one partition for older data. All newer months should have an dedicated partition, whereas partitions for upcoming months shall be created automatically.
How can this be integrating into the already existing partitoning?
You cannot do it exactly the way you want. Partitioning strategies are limited in two relevant ways: first, composite strategies can only have two levels (you need 3) and second, interval partitioning, when used in a composite strategy must be at the top level.
Here is the closest legal thing to what you want:
CREATE TABLE matt_customer
(
incident_id NUMBER,
customer_id NUMBER,
customer_name VARCHAR2 (400),
sla_id NUMBER,
failure_start_date DATE,
failure_end_date DATE,
churn_flag VARCHAR2 (1), -- 0 or 1
active VARCHAR2 (1), -- 0 or 1
active_churn_flags VARCHAR2 (2) GENERATED ALWAYS AS (active || churn_flag) VIRTUAL,
CONSTRAINT pk_incident_id PRIMARY KEY (incident_id)
)
PARTITION BY RANGE
(failure_start_date)
INTERVAL ( NUMTOYMINTERVAL (1, 'MONTH') )
SUBPARTITION BY LIST
(active_churn_flags)
SUBPARTITION TEMPLATE (
SUBPARTITION sp_ac_00 VALUES ('00'),
SUBPARTITION sp_ac_01 VALUES ('01'),
SUBPARTITION sp_ac_10 VALUES ('10'),
SUBPARTITION sp_ac_11 VALUES ('11'))
(PARTITION customer_old VALUES LESS THAN (TO_DATE ('01-JAN-2013', 'DD-MON-YYYY')))
ENABLE ROW MOVEMENT
--COMPRESS FOR QUERY LOW;
;
This uses interval-list partitioning, and uses a virtual column to combine your active and churn_flag columns into one (I turned those columns into VARCHAR2(1) for simplicity.
To make use of partition pruning, your queries would need to be modified to select active_churn_flags = '01' for example, instead of specifying values for active and churn_flag independently.
This question already has answers here:
How to create id with AUTO_INCREMENT on Oracle?
(18 answers)
Closed 8 years ago.
I am facing issue while inserting multiple row in one go into table because column id has primary key and its created based on sequence.
for ex:
create table test (
iD number primary key,
name varchar2(10)
);
insert into test values (123, 'xxx');
insert into test values (124, 'yyy');
insert into test values (125, 'xxx');
insert into test values (126, 'xxx');
The following statement creates a constraint violoation error:
insert into test
(
select (SELECT MAX (id) + 1 FROM test) as id,
name from test
where name='xxx'
);
This query should insert 3 rows in table test (having name=xxx).
You're saying that your query inserts rows with primary key ID based on a sequence. Yet, in your insert/select there is select (SELECT MAX (id) + 1 FROM test) as id, which clearly is not based on sequence. It may be the case that you are not using the term "sequence" in the usual, Oracle way.
Anyway, there are two options for you ...
Create a sequence, e.g. seq_test_id with the starting value of select max(id) from test and use it (i.e. seq_test_id.nextval) in your query instead of the select max(id)+1 from test.
Fix the actual subselect to nvl((select max(id) from test),0)+rownum instead of (select max(id)+1 from test).
Please note, however, that the option 2 (as well as your original solution) will cause you huge troubles whenever your code runs in multiple concurrent database sessions. So, option 1 is strongly recommended.
Use
insert into test (
select (SELECT MAX (id) FROM test) + rownum as id,
name from test
where name='xxx'
);
as a workaround.
Of course, you should be using sequences for integer-primary keys.
If you want to insert an ID/Primary Key value generated by a sequence you should use the sequence instead of selecting the max(ID)+1.
Usually this is done using a trigger on your table wich is executed for each row. See sample below:
CREATE TABLE "MY_TABLE"
(
"MY_ID" NUMBER(10,0) CONSTRAINT PK_MY_TABLE PRIMARY KEY ,
"MY_COLUMN" VARCHAR2(100)
);
/
CREATE SEQUENCE "S_MY_TABLE"
MINVALUE 1 MAXVALUE 999999999999999999999999999
INCREMENT BY 1 START WITH 10 NOCACHE ORDER NOCYCLE NOPARTITION ;
/
CREATE OR REPLACE TRIGGER "T_MY_TABLE"
BEFORE INSERT
ON
MY_TABLE
REFERENCING OLD AS OLDEST NEW AS NEWEST
FOR EACH ROW
WHEN (NEWEST.MY_ID IS NULL)
DECLARE
IDNOW NUMBER;
BEGIN
SELECT S_MY_TABLE.NEXTVAL INTO IDNOW FROM DUAL;
:NEWEST.MY_ID := IDNOW;
END;
/
ALTER TRIGGER "T_MY_TABLE" ENABLE;
/
insert into MY_TABLE (MY_COLUMN) values ('DATA1');
insert into MY_TABLE (MY_COLUMN) values ('DATA2');
insert into MY_TABLE (MY_ID, MY_COLUMN) values (S_MY_TABLE.NEXTVAL, 'DATA3');
insert into MY_TABLE (MY_ID, MY_COLUMN) values (S_MY_TABLE.NEXTVAL, 'DATA4');
insert into MY_TABLE (MY_COLUMN) values ('DATA5');
/
select * from MY_TABLE;
This question already has answers here:
Using sequential values for the primary key in an INSERT query
(2 answers)
Closed 9 years ago.
I am trying to load a column with unique sequence number each time a row of data is insrerted in the table.How can this be achieved?
You can create a Sequence, and then use the sequence nextval in your insert statements for the column which you want to have sequential incremented value.
CREATE SEQUENCE seq
INCREMENT BY 1
START WITH 1
NOMAXVALUE
NOCYCLE
CACHE 10;
INSERT INTO tab VALUES (seq.nextval, col1, col2, col3);
there is nothing like "auto_increment" or "identity" in Oracle,
but if you want auto increment in your column value you can use Sequence for the this.
after creating sequence you can use After Insert Trigger to insert identical value.
here is trigger example...
CREATE OR REPLACE TRIGGER dep_ins_trig
BEFORE INSERT ON <table_name>
FOR EACH ROW
BEGIN
SELECT dept_seq.NEXTVAL
INTO :new.id
FROM dual;
END;
/
This is achieved by Trigger and Sequence 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.
Let say I have table my table has values(which they are varchar):
values
a
o
g
t
And I have insert a new value called V
values
V
a
o
g
t
Is there a way or query that can specify what is the last value was insert in the column ? the desired query : select * from dual where rown_num = count(*) -- just an example and the result will be V
Rows in a table have no inherent order. rownum is a pseudocolumn that's part of the select so it isn't useful here. There is no way to tell where in the storage a new row will physically be placed, so you can't rely on rowid, for example.
The only way to do this reliably is to have a timestamp column (maybe set by a trigger so you don't have to worry about it). That would let you order the rows by timestamp and find the row with the highest (most recent) timestamp.
You are still restricted by the precision of the timestamp, as I discovered creating a SQL Fiddle demo; without forcing a small gap between the inserts the timestamps were all the same, but then it only seems to support `timestamp(3). That probably won't be a significant issue in the real world, unless you're doing bulk inserts, but then the last row inserted is still a bit of an arbitrary concept.
As quite correctly pointed out in comments, if the actual time doesn't need to be know, a numeric field populated by a sequence would be more reliable and performant; another SQL Fiddle demo here, and this is the gist:
create table t42(data varchar2(10), id number);
create sequence seq_t42;
create trigger bi_t42
before insert on t42
for each row
begin
:new.id := seq_t42.nextval;
end;
/
insert into t42(data) values ('a');
insert into t42(data) values ('o');
insert into t42(data) values ('g');
insert into t42(data) values ('t');
insert into t42(data) values ('V');
select data from (
select data, row_number() over (order by id desc) as rn
from t42
)
where rn = 1;
In my vb application I want an autogenerated id of alphanumeric characters, like prd100. How can I increment it using Oracle as backend?
Any particular reason it needs to be alphanumeric? If it can just be a number, you can use an Oracle sequence.
But if you want just a random string, you could use the dbms_random function.
select dbms_random.string('U', 20) str from dual;
So you could probably combine these 2 ideas (in the code below, the sequence is called oid_seq):
SELECT dbms_random.string('U', 20) || '_' || to_char(oid_seq.nextval) FROM dual
There are two parts to your question. The first is how to create an alphanumeric key. The second is how to get the generated value.
So the first step is to determine the source of the alpha and the numeric components. In the following example I use the USER function and an Oracle sequence, but you will have your own rules. I put the code to assemble the key in a trigger which is called whenever a row is inserted.
SQL> create table t1 (pk_col varchar2(10) not null, create_date date)
2 /
Table created.
SQL> create or replace trigger t1_bir before insert on t1 for each row
2 declare
3 n pls_integer;
4 begin
5 select my_seq.nextval
6 into n
7 from dual;
8 :new.pk_col := user||trim(to_char(n));
9 end;
10 /
Trigger created.
SQL>
The second step requires using the RETURNING INTO clause to retrieve the generated key. I am using SQL*PLus for this example. I confess to having no idea how to wire this syntax into VB. Sorry.
SQL> var new_pk varchar2(10)
SQL> insert into t1 (create_date)
2 values (sysdate)
3 returning pk_col into :new_pk
4 /
1 row created.
SQL> print new_pk
NEW_PK
--------------------------------
APC61
SQL>
Finally, a word of warning.
Alphanumeric keys are a suspicious construct. They reek of "smart keys" which are, in fact, dumb. A smart key is a value which contains multiple parts. At somepoint you will find yourself wanting to retrieving all rows where the key starts with 'PRD', which means using SUBSTR() or LIKE. Even worse someday the definition of the smart key will change and you will have to cascade a complicated update to your table and its referencing foreign keys. A better ides is to use a surrogate key (number) and have the alphanumeric "key" defined as separate columns with a UNIQUE composite constraint to enforce the business rule.
SQL> create table t1 (id number not null
2 , alpha_bit varchar2(3) not null
3 , numeric_bit number not null
4 , create_date date
5 , constraint t1_pk primary key (id)
6 , constraint t1_uk unique (alpha_bit, numeric_bit)
7 )
8 /
Table created.
SQL>