I want create a table 'product' and have a column date, is it possible that current date will be added when I add some info to table?
If yes please example of this table
create table products (
id number not null,
date number not null
);
Assuming that
Your column is not actually named date since that is a reserved word
Your column is actually defined as a date rather than as a number
You want to populate the column when you insert a new row
you can define a default value for the column.
SQL> ed
Wrote file afiedt.buf
1 create table products (
2 id number not null,
3 dt date default sysdate not null
4* )
SQL> /
Table created.
SQL>
SQL> insert into products( id ) values( 1 );
1 row created.
SQL> select * from products;
ID DT
---------- ---------
1 20-NOV-12
If you want to modify the dt column when you UPDATE the row, you would need a trigger
CREATE OR REPLACE TRIGGER trg_products
BEFORE INSERT OR UPDATE ON products
FOR EACH ROW
BEGIN
:new.dt := sysdate;
END;
A trigger will override any value passed in as part of the INSERT or UPDATE statement for the dt column. A default value will not.
Related
we have an api operation that enters a row into our table with a report_type=5, is there some sort of operation i can apply to the table to make it so whenever a record gets entered or pulled
with a report_id=12 it returns the report_type as 4?
As commented, trigger would do. Here's an example.
Sample table:
SQL> create table test
2 (report_id number,
3 report_type number);
Table created.
Trigger:
SQL> create or replace trigger trg_bi_test
2 before insert on test
3 for each row
4 when (new.report_id = 12)
5 begin
6 :new.report_type := 4;
7 end;
8 /
Trigger created.
Testing:
SQL> insert into test (report_id, report_type) values (1, 13);
1 row created.
SQL> insert into test (report_id, report_type) values (12, 99);
1 row created.
SQL> select * from test;
REPORT_ID REPORT_TYPE
---------- -----------
1 13
12 4 --> I inserted report_type = 99, but trigger modified it to 4
--> because report_id = 12
SQL>
It's not clear which value you want to be STORED in the database: 12 (as entered), or 4 (as translated).
A trigger as proposed by another commenter would certainly be able to translate the value on insert or update.
If you want the original value to be stored, you'd need to set up a different column, that is derived based on the original one. An example swiped from an Oracle publication:
create table PERSON (
(employee_id integer,
employee_id_disp computed by
SUBSTRING (CAST(employee_id + 100000 as VARCHAR (6)) from 2)
);
In your case, you might do something like
create table MYTABLE (
somekey varchar(20) not null,
entered_office int,
display_office computed by decode(entered_office,12,4,entered_office)
);
Then, anything that needs to display the office number would need to use the display_office field, not the entered one. Any tool that does an insert into the table would also need to insert the entered_office field, as display_office is not updateable.
I want to create something that will update my data in table automaticly but i don't know what to use.
i have nr1 table
create table NR1
(
id INTEGER not null,
price INTEGER,
price2 INTEGER,
start_date DATE,
end_date DATE,
duration NUMBER
)
and i tried to create trigger which will update always after inserting or updateing my table, end_date, so i tried something like this:
create or replace trigger update_nr1_date
after update or insert on nr1
for each row
when (new.id>0)
declare
begin
UPDATE nr1
set nr1.end_date =add_months(nr1.start_date, nr1.duration);
end;
but it have mutation problems, and i read something about that, and i udersatnd the concept of this. I want to make trigger like this (not sheduler, because i want to get it automaticly after inserting or updating some rows). Is it possible while inserting data to table it itself refill missing columns?
Your trigger needs to before update in order to change the value in the row the trigger is fired again; and it needs to modify the current row's (new) pseudorecord via an assignment statement - you should not be issuing a separate update statement inside the trigger. It will cascade, for a start, and in your example woudl try to update every row in the table. But that is also causing the mutating table error - you're trying to update rows in the table the trigger is against. There are workarounds when that is actually necessary, but it isn't here, that update should just not be there.
So you would do:
create or replace trigger update_nr1_date
before update or insert on nr1
for each row
when (new.id>0)
begin
:new.end_date := add_months(:new.start_date, :new.duration);
end;
/
But if you're on 11g or higher you can use a virtual column instead, without needing a trigger at all:
create table NR1
(
id INTEGER not null,
price INTEGER,
price2 INTEGER,
start_date DATE,
end_date DATE generated always as (add_months(start_date, duration)) virtual,
duration NUMBER
)
Then when you insert, skip that column in the statement:
insert into nr1 (id, price, price2, start_date, duration)
values (1, 2, 3, date '2018-06-01', 3);
1 row inserted.
select * from nr1 where id = 1;
ID PRICE PRICE2 START_DATE END_DATE DURATION
---------- ---------- ---------- ---------- ---------- ----------
1 2 3 2018-06-01 2018-09-01 3
The end date always reflects the values of the other two columns.
I have a large number of rows that i want to insert simultaneously into a PostgreSQL database. I need to track what id is assigned for each row that is inserted. For example say we have the table:
CREATE TABLE example
(
id serial,
name text,
CONSTRAINT example_pkey PRIMARY KEY (id),
);
Now i have some data with ids that i dont want inserted (as the serial id column will assign a new id), but i need to keep track of the mapping between the old id and new id:
old id | name
-------------
-1 | foo
-2 | bar
-3 | baz
So i wrote this query
WITH data(oldid,name) AS ( VALUES
(-1,'foo'),
(-2,'bar'),
(-3,'baz')
)
INSERT INTO example(name)
SELECT name FROM data d
RETURNING id, d.oldid
Expecting to get something back like:
id | oldid
-----------
1 | -1
2 | -2
3 | -3
However this doesn't work, as i don't believe you can return a column that wasn't inserted. Is there any alternative way to do this?
I ended up creating a function that wrapped the inserting of a single row:
CREATE OR REPLACE FUNCTION add_example(
in_name text)
RETURNS integer AS
$BODY$
DECLARE
new_id integer;
BEGIN
INSERT INTO example(name)
VALUES (in_name) RETURNING id INTO new_id;
RETURN new_id;
END;
$BODY$
LANGUAGE plpgsql;
Then i can do:
WITH data(oldid, name) AS (VALUES
(-1,'foo'),
(-2,'bar'),
(-3,'baz')
)
SELECT oldid, add_example(name) AS id
FROM data
Which returns what i expect. I'd like to see if this can be done without the function though.
CREATE SEQUENCE data_id_seq;
CREATE TABLE DATA (
id integer default nextval('data_id_seq') NOT NULL PRIMARY KEY,
oldid integer,
name text,
);
INSERT INTO DATA(oldid,name) values (-1,'foo'),(-2,'bar'),(-3,'baz') returning id,oldid;
The optional RETURNING clause causes INSERT to compute and return
value(s) based on each row actually inserted
from https://www.postgresql.org/docs/current/static/sql-insert.html
so column parasite is unavoidable for such solution:
alter table example add column old bigint;
WITH d(oldid,name) AS ( VALUES
(-1,'foo'),
(-2,'bar'),
(-3,'baz')
)
INSERT INTO example(name,old)
SELECT "name", oldid FROM d
RETURNING id, old
I have a table named TABLE_1 which has 3 columns
row_id row_name row_descr
1 check1 checks here
2 check2 checks there
These rows are created through a front end application. Now suppose I delete the entry with row_name check2 from the front end and create another entry from front end with row_name check3, in database my entries will be as follows.
row_id row_name row_descr
1 check1 checks here
3 check3 checks
Now row_id if you observe is not a normal one time increment, Now my problem is i'm writing an insert statement to automate something and i don't know what i should insert in the row_id column. Previously i thought it is just new row_id = old row_id +1. But this is not the case here. Please help
EDIT :
Currently im inserting like this which is Wrong :
insert into TABLE1 (row_id, row_name, row_descr
) values ( (select max (row_id) + 1 from TABLE1),'check1','checks here');
row_id is not a normal one time increment.
Never ever calculate ids by max(id)+1 unless you can absolutly exclude simultaneous actions ( which is almost never ever the case). In oracle (pre version 12 see Kumars answer) create a sequence once and insert the values from that sequences afterwards.
create sequence my_sequence;
Either by a trigger which means you don't have to care about the ids during the insert at all:
CREATE OR REPLACE TRIGGER myTrigger
BEFORE INSERT ON TABLE1 FOR EACH ROW
BEGIN
SELECT my_sequence.NEXTVAL INTO :NEW.row_id FROM DUAL;
END;
/
Or directly with the insert
insert into TABLE1 (row_id, row_name, row_descr
) values ( my_sequence.nextval,'check1','checks here');
Besides using row_id as column name in oracle might be a little confusing, because of the pseudocolumn rowid which has a special meaning.
To anwser your quetstion though: If you really need to catch oracle errors as excpetions you can do this with PRAGMA EXCEPTION INIT by using a procedure for your inserts. It might look somehow like this:
CREATE OR REPLACE PROCEDURE myInsert( [...] )
IS
value_allready_exists EXCEPTION;
PRAGMA EXCEPTION_INIT ( value_allready_exists, -00001 );
--ORA-00001: unique constraint violated
BEGIN
/*
* Do your Insert here
*/
EXCEPTION
WHEN value_allready_exists THEN
/*
* Do what you think is necessary on your ORA-00001 here
*/
END myInsert;
Oracle 12c introduced IDENTITY columns. Precisely, Release 12.1. It is very handy with situations where you need to have a sequence for your primary key column.
For example,
SQL> DROP TABLE identity_tab PURGE;
Table dropped.
SQL>
SQL> CREATE TABLE identity_tab (
2 ID NUMBER GENERATED ALWAYS AS IDENTITY,
3 text VARCHAR2(10)
4 );
Table created.
SQL>
SQL> INSERT INTO identity_tab (text) VALUES ('Text');
1 row created.
SQL> DELETE FROM identity_tab WHERE ID = 1;
1 row deleted.
SQL> INSERT INTO identity_tab (text) VALUES ('Text');
1 row created.
SQL> INSERT INTO identity_tab (text) VALUES ('Text');
1 row created.
SQL> INSERT INTO identity_tab (text) VALUES ('Text');
1 row created.
SQL> DELETE FROM identity_tab WHERE ID = 2;
1 row deleted.
SQL> SELECT * FROM identity_tab;
ID TEXT
---------- ----------
3 Text
4 Text
SQL>
Now let's see what's under the hood -
SQL> SELECT table_name,
2 column_name,
3 generation_type,
4 identity_options
5 FROM all_tab_identity_cols
6 WHERE owner = 'LALIT'
7 /
TABLE_NAME COLUMN_NAME GENERATION IDENTITY_OPTIONS
-------------------- --------------- ---------- --------------------------------------------------
IDENTITY_TAB ID ALWAYS START WITH: 1, INCREMENT BY: 1, MAX_VALUE: 9999999
999999999999999999999, MIN_VALUE: 1, CYCLE_FLAG: N
, CACHE_SIZE: 20, ORDER_FLAG: N
SQL>
So, there you go. A sequence implicitly created by Oracle.
And don't forget, you can get rid off the sequence only with the purge option with table drop.
If you are not worried about which values are causing the error, then you could handle it by including a /*+ hint */ in the insert statement.
Here is an example where we would be selecting from another table, or perhaps an inner query, and inserting the results into a table called TABLE_NAME which has a unique constraint on a column called IDX_COL_NAME.
INSERT /*+ ignore_row_on_dupkey_index(TABLE_NAME(IDX_COL_NAME)) */
INTO TABLE_NAME(
INDEX_COL_NAME
, col_1
, col_2
, col_3
, ...
, col_n)
SELECT
INDEX_COL_NAME
, col_1
, col_2
, col_3
, ...
, col_n);
Oracle will blow past the redundant row. This is not a great solution if you care about know WHICH row is causing the issue, or anything else. But if you don't care about that and are fine just keeping the first value that was inserted, then this should do the job.
You can use an exception build in which will raise whenever there will be duplication on unique key
DECLARE
emp_count number;
BEGIN
select count(*) into emp_count from emp;
if emp_count < 1 then
insert into emp
values(1, 'First', 'CLERK', '7839', SYSDATE, 1200, null, 30);
dbms_output.put_line('Clerk added');
else
dbms_output.put_line('No data added');
end if;
EXCEPTION
when dup_val_on_index then
dbms_output.put_line('Tried to add row with duplicated index');
END;
I am doing an insert and delete operation on a table in single transaction.I have trigger on this table which update the log.The log has primary key as sequenceId which always gets incremented on insertion.I do delete first and then insert in the transaction.
I have two issues :
The timestamp in the log for the insert and delete is being same. Can I force it to be different.
The order of operation(insert/delete) in the log is getting reversed. It shows delete operation coming after insert operation(according to sequenceId).How can I ensure that the order is consistent in the log(insert after delete).
Example :
create table address (ID number, COUNTRY char(2));
create table address_log(SEQ_ID number, ID number, COUNTRY char(2), DML_TYPE char(1), CHANGE_DATE timestamp(6));
create sequence seq_id start with 1 increment by 100 nominvalue nomaxvalue cache 20 noorder;
create or replace trigger trg_add
before insert or delete on address
FOR EACH ROW
BEGIN
if inserting then
insert into address_log values(SEQ_ID.nextval, :new.ID, :new.COUNTRY, 'I', sysdate);
else
insert into address_log values(SEQ_ID.nextval, :old.ID, :old.COUNTRY, 'D', sysdate);
end if;
end;
insert into address values(1,'US');
insert into address values(2,'CA');
delete from address where id = 1;
insert into address values(3,'UK');
delete from address where id = 3;
if I commit last DML queries in single transaction, then I should see the same order in address_log.
What is the datatype of your timestamp column?
If you use TIMESTAMP with a large enough precision, the order should be preserved.
For example TIMESTAMP(6) (precision to the micro-second) -- which is the default precision:
SQL> CREATE TABLE t_data (ID NUMBER, d VARCHAR2(30));
Table created
SQL> CREATE TABLE t_log (ts TIMESTAMP (6), ID NUMBER, action VARCHAR2(1));
Table created
SQL> CREATE OR REPLACE TRIGGER trg
2 BEFORE INSERT ON t_data
3 FOR EACH ROW
4 BEGIN
5 INSERT INTO t_log VALUES (systimestamp, :NEW.id, 'I');
6 END;
7 /
Trigger created
SQL> INSERT INTO t_data (SELECT ROWNUM, 'x' FROM dual CONNECT BY LEVEL <= 10);
10 rows inserted
SQL> SELECT * FROM t_log ORDER BY ts;
TS ID ACTION
----------------------------- ---------- ------
19/06/13 15:47:51,686192 1 I
19/06/13 15:47:51,686481 2 I
19/06/13 15:47:51,686595 3 I
19/06/13 15:47:51,686699 4 I
19/06/13 15:47:51,686800 5 I
19/06/13 15:47:51,686901 6 I
...
In any case, if you really want to distinguish simultaneous events (concurrent inserts for instance), you can always use a sequence in addition, with the ORDER keyword to guarantee that the rows will be ordered:
CREATE SEQUENCE log_sequence ORDER
This would allow you to have a reliable sort order, even though the events took place at the same time.