I have a function my_func, the input of this function is one of the column in the same row after insertion, how to achieve this.
I have created the table using,
create table sample_trigger_hash ( INDEXID number(19,0) ,
XMLCOLUMN XMLTYPE ,
CHECKFIELD RAW(30)
) XMLTYPE COLUMN XMLCOLUMN STORE AS BINARY XML;
I am thinking of an insertion statement from DBD::Oracle in perl , with just the first two fields.
The following is my trigger,
CREATE OR REPLACE
TRIGGER hash_trigger
AFTER INSERT ON sample_trigger_hash
REFERENCING NEW AS NEW OLD AS OLD
FOR EACH ROW
BEGIN
SELECT my_hash(EXTRACT(:OLD.XMLCOLUMN ,''))
INTO :NEW.CHECKFIELD
FROM dual;
END hash_trigger;
Am getting the error,
ORA-04084: cannot change NEW values for this trigger type
04084. 00000 - "cannot change NEW values for this trigger type"
*Cause: New trigger variables can only be changed in before row
insert or update triggers.
*Action: Change the trigger type or remove the variable reference.
But my requirement is to get the XMLType value after insertion, how to achieve this. If I use CLOB storage option for the XMLType, I am getting the same hash value before storing and after storing. But this is not the case when I store it as binary XML. (an XSI section is added to the binary version) More details in this other question.
Your requirement doesn't make sense. You want to include the hashed value in the newly inserted row, so put the function in a before insert trigger.
Related
I have a problem with trigger created to invoke before insert method.
For example, i have 3 columns in my table and 1 of these columns is inserted by trigger.
When i want to insert all data(into all columns) by myself trigger overwrites data in specified column.
The trigger is specified to invoke before insert command so i though that insert command will overwrite data in column specified in trigger.
Do anyone know how to solve this issue?
Is this possible for me to insert all data by myself when i have created a trigger?
How can I change DATA TYPE of a column from number to varchar2 without deleting the table data?
You can't.
You can, however, create a new column with the new data type, migrate the data, drop the old column, and rename the new column. Something like
ALTER TABLE table_name
ADD( new_column_name varchar2(10) );
UPDATE table_name
SET new_column_name = to_char(old_column_name, <<some format>>);
ALTER TABLE table_name
DROP COLUMN old_column_name;
ALTER TABLE table_name
RENAME COLUMN new_column_name TO old_coulumn_name;
If you have code that depends on the position of the column in the table (which you really shouldn't have), you could rename the table and create a view on the table with the original name of the table that exposes the columns in the order your code expects until you can fix that buggy code.
You have to first deal with the existing rows before you modify the column DATA TYPE.
You could do the following steps:
Add the new column with a new name.
Update the new column from old column.
Drop the old column.
Rename the new column with the old column name.
For example,
alter table t add (col_new varchar2(50));
update t set col_new = to_char(col_old);
alter table t drop column col_old cascade constraints;
alter table t rename column col_new to col_old;
Make sure you re-create any required indexes which you had.
You could also try the CTAS approach, i.e. create table as select. But, the above is safe and preferrable.
The most efficient way is probably to do a CREATE TABLE ... AS SELECT
(CTAS)
alter table table_name modify (column_name VARCHAR2(255));
Since we can't change data type of a column with values, the approach that I was followed as below,
Say the column name you want to change type is 'A' and this can be achieved with SQL developer.
First sort table data by other column (ex: datetime).
Next copy the values of column 'A' and paste to excel file.
Delete values of the column 'A' an commit.
Change the data type and commit.
Again sort table data by previously used column (ex: datetime).
Then paste copied data from excel and commit.
I am using an AFTER INSERT row trigger in Oracle 11g to copy specific columns from one table to another on insert. I have the trigger and insert working ok. The problem I have is that I need to insert the new data from one column to a different column when copying it.
The trigger info reads:
BEGIN
insert into BALES_STORAGE
(CROP,
CUTTING,
DESTINATION,
BALES_MOVED,
DATE_MOVED,
PASTURE,
TARGET_LB_PER_DAY)
values
(:new.CROP,
:new.CUTTING,
:new.MOVING_LOCATION,
:new.BALES_MOVED,
:new.DATE_MOVED,
:new.PASTURE,
:new.TARGET_LB_PER_DAY);
END;
The first table is called "BALES_HARVESTED" and the 2nd table the trigger inserts the selected columns into is called "BALES_STORAGE". I need to insert the :new.MOVING_LOCATION data into the column called DESTINATION on the second table.
So my question is: when using an after insert row trigger, how to I change the column that the data is inserted into?
Thanks for any help.
Matthew
Your trigger code worked just fine for me. Not sure what the problem is. The 3rd column in your INSERT statement does the column mapping correctly.
http://sqlfiddle.com/#!4/2d2fd5/1/1
Maybe you have different structures or foreign key constraints. Could you elaborate on what error you get? Does it produce an ORA- error? or does it simply not produce the desired result, but no error?
I'm trying to update some existing code that is supposed to write data to a variety of Databases (SQL, Access, Oracle) via ODBC, but I'm having a few problems with Oracle and am looking for any suggestions.
I've set my Oracle database up using a Trigger (basic tutorial online, which I'd like to support).
CREATE TABLE TABLE1 (
RECORDID NUMBER NOT NULL PRIMARY KEY,
ID VARCHAR(40) NULL,
COUNT NUMBER NULL
);
GO
CREATE SEQUENCE TABLE1_SEQ
GO
CREATE or REPLACE TRIGGER TABLE1_TRG
BEFORE INSERT ON TABLE1
FOR EACH ROW
WHEN (new.RECORDID IS NULL)
BEGIN
SELECT TABLE1_SEQ.nextval
INTO :new.RECORDID
FROM dual;
end;
GO
I then populate a DataTable using a SELECT * FROM TABLE1. The first problem is that this DataTable doesn't know that the RecordId column is auto-generated. If I have data in my table then I can't alter it because I get a error
Cannot change AutoIncrement of a DataColumn with type 'Double' once it
has data.
If I continue, ignoring this, then I quickly get stuck. If I create a new DataRow and try to insert it, I can't set RecordID to DBNull.Value because it complains that the column has to be non-null (NoNullAllowedException). I can't however generate a value myself, because I don't know what value I should be using really, and don't want to screw up the trigger by using the next available value.
Any suggestions on how I should insert data without ODBC complaining?
It does not appear that your first problem is with an Oracle database. There is no such thing as an "Autoincrement" column in Oracle. Are you sure that message is coming from an Oracle database?
With Oracle, you should be able to provide any dummy value on insert for the primary key, and the trigger will overwrite it.
There is also nothing in your provided description that would prevent you from updating this value in Oracle (since your trigger is on insert only) unless you have foreign key references to the key.
Hi I have a database with loads of columns and I want to insert couple of records for testing, now in order to insert something into that database I'd have to write large query .. is it possible to do something like this
INSERT INTO table (SELECT FROM table WHERE id='5') .. I try to insert the row with ID 5 but I think this will create a problem because it will try to duplicate a record, is it possible to change this ID 5 to let say 1000 then I'd be able to insert data without writing complex query and while doing so avoiding replication of data .. tnx
In PL/SQL you can do something like this:
declare
l_rec table%rowtype;
begin
select * into l_rec from table where id='5';
l_rec.id := 1000;
insert into table values l_rec;
end;
If you have a trigger on the table to handle the primary key from a sequence (:NEW.id = seq_sequence.NEXTVAL) then you should be able to do:
INSERT INTO table
(SELECT columns_needed FROM table WHERE whatever)
This will allow you to add in many rows at one (the number being limited by the WHERE clause). You'll need to select the columns that are required by the table to be not null or not having default values. Beware of any unique constraints as well.
Otherwise you'll be looking at PL/SQL or some other form of script to insert multiple rows.
For each column that has no default value or you want to insert the values other than default, you will need to provide the explicit name and value.
You only can use an implicit list (*) if you want to select all columns and insert them as they are.
Since you are changing the PRIMARY KEY, you need to enumerate.
However, you can create a before update trigger and change the value of the PRIMARY KEY in this trigger.
Note that the trigger cannot reference the table itself, so you will need to provide some other way to get the unique number (like a sequence):
CREATE TRIGGER trg_mytable_bi BEFORE INSERT ON mytable FOR EACH ROW
BEGIN
:NEW.id := s_mytable.nextval;
END;
This way you can use the asterisk but it will always replace the value of the PRIMARY KEY.