I have a table test_123 with the column as:
int_1 (int),
datetime_1 (datetime),
tinyint_1 (tinyint),
datetime_2 (datetime)
So when column datetime_1 is updated and the value at column tinyint_1 = 1 that time i have to update my column datetime_2 with column value of datetime_1
I have created the below trigger for this.. but with my trigger it is updating all datetime2 column values with datetime_1 column when tinyint_1 = 1 .. but i just want to update that particular row where datetime_1 value has updated( i mean changed)..
Below is the trigger..
CREATE TRIGGER test_trigger_upd
ON test_123
FOR UPDATE
AS
FOR EACH STATEMENT
IF UPDATE(datetime_1)
BEGIN
UPDATE test_123
SET test_123.datetime_2 = inserted.datetime_1
WHERE test_123.tinyint_1 = 1
END
ROW-level triggers are not supported in ASE. There are only after-statement triggers.
As commented earlier, the problem you're facing is that you need to be able to link the rows in the 'inserted' pseudo-table to the base table itself. You can only do that if there is a key -- meaning: a column that uniquely identifies a row, or a combination of columns that does so. Without that, you simply cannot identify the row that needs to be updated, since there may be multiple rows with identical column values if uniqueness is not guaranteed.
(and on a side note: not having a key in a table is bad design practice -- and this problem is one of the many reasons why).
A simple solution is to add an identity column to the table, e.g.
ALTER TABLE test_123 ADD idcol INT IDENTITY NOT NULL
You can then add a predicate 'test_123.idcol = inserted.idcol' to the trigger join.
Related
I am trying to insert extracted data from a sql table into a postgres table where the rows may or may not exist. If they do exist, I would like to set a specific column to its default (0)
The table is as
site_notes (
job_id text primary key,
attachment_id text,
complete int default 0);
My query is
INSERT INTO site_notes (
job_id,
attachment_id
)
VALUES
{jobs_sql}
ON CONFLICT (job_id) DO UPDATE
SET complete = DEFAULT;
However I am getting an error: psycopg2.errors.CardinalityViolation: ON CONFLICT DO UPDATE command cannot affect row a second time
HINT: Ensure that no rows proposed for insertion within the same command have duplicate constrained values.
Would anyone be able to advise on how to set the complete column to the default on event of a conflict ?
Many Thanks
An INSERT ... ON CONFLICT DO UPDATE statement (and indeed an UPDATE statement too) is not allowed to modify the same row more than once. It is not clear what {jobs_sql} in your question is, but it must contain several rows, and at least two of those have the same job_id.
Make sure that the same job_id does not occur more than once in the rows you want to INSERT.
I've created table projects like so:
CREATE TABLE projects (
project_id NUMBER(10,0) GENERATED BY DEFAULT ON NULL AS IDENTITY ,
project_name VARCHAR2(75 CHAR) NOT NULL
Then I've inserted ~150,000 rows while importing data from my old MySQL table. the MySQL had existing id numbers which i need to preserve so I added the id number to the SQL during the insert. Now when I insert new rows into the oracle table, the id is a very low number. Can you tell me how to reset my counter on the project_id column to start at 150,001 so not to mess up any of my existing id numbers? essentially i need the oracle version of:
ALTER TABLE tbl AUTO_INCREMENT = 150001;
Edit: Oracle 12c now supports the identity data type, allowing an auto number primary key that does not require us to create a sequence + insert trigger.
SOLUTION:
after some creative google search terms I was able to find this thread on the oracle docs site. here is the solution for changing the identity's nextval:
ALTER TABLE projects MODIFY project_id GENERATED BY DEFAULT ON NULL AS IDENTITY ( START WITH 150000);
Here is the solution that i found on this oracle thread:. The concept is to alter your identity column rather than adjust the sequence. Actually, the sequences that are automatically created aren't editable or drop-able.
ALTER TABLE projects MODIFY project_id GENERATED BY DEFAULT ON NULL AS IDENTITY ( START WITH 150000);
According to this source, you can do it like this:
ALTER TABLE projects MODIFY project_id
GENERATED BY DEFAULT ON NULL AS IDENTITY (START WITH LIMIT VALUE);
The START WITH LIMIT VALUE clause can only be specified with an ALTER TABLE statement (and by implication against an existing identity column). When this clause is specified, the table will be scanned for the highest value in the PROJECT_ID column and the sequence will commence at this value + 1.
The same is also stated in the oracle thread referenced in OP's own answer:
START WITH LIMIT VALUE, which is specific to identity_options, can only be used with ALTER TABLE MODIFY. If you specify START WITH LIMIT VALUE, then Oracle Database locks the table and finds the maximum identity column value in the table (for increasing sequences) or the minimum identity column value (for decreasing sequences) and assigns the value as the sequence generator's high water mark. The next value returned by the sequence generator will be the high water mark + INCREMENT BY integer for increasing sequences, or the high water mark - INCREMENT BY integer for decreasing sequences.
The following statement creates the sequence customers_seq in the sample schema oe. This sequence could be used to provide customer ID numbers when rows are added to the customers table.
CREATE SEQUENCE customers_seq
START WITH 1000
INCREMENT BY 1
NOCACHE
NOCYCLE;
The first reference to customers_seq.nextval returns 1000. The second returns 1001. Each subsequent reference will return a value 1 greater than the previous reference.
http://docs.oracle.com/cd/B12037_01/server.101/b10759/statements_6014.htm
I have a table a Postgres 9.04 database with a table in it called Versions:
CREATE TABLE tracking."Versions"
(
"ObjectId" UUID NOT NULL,
"From" BIGINT NOT NULL,
"To" BIGINT,
"DataTypeId" INTEGER NOT NULL REFERENCES tracking."DataTypes" ( "DataTypeId" ),
CONSTRAINT "Versions_pkey" PRIMARY KEY ("ObjectId", "DataTypeId")
);
There is also a sequence defined in the database that is used by the From & To columns:
CREATE SEQUENCE tracking."dbVersion"
INCREMENT 1
MINVALUE 1
MAXVALUE 9223372036854775807
START 1
CACHE 1;
The Versions table is actually keeping track of changes made to other tables. Without going into the details:
When a row is created in one of these other tables, a row is added to the Versions table and the From column is supposed to be set to the next value of the sequence.
If an existing row in one of those tables is updated, the From value of the corresponding row in the Versions table has to be set to the next value of the sequence.
When a row in one of these other tables is deleted, the To column has to be set to the next value of the sequence.
Rather than setting the Default value of the From column to "nextval('tracking."dbVersion'), I implemented a stored function that returns the result of calling this function:
CREATE OR REPLACE FUNCTION tracking."NextVersion"() RETURNS BIGINT
AS $$
SELECT nextval('tracking."dbVersion"'::regclass);
$$ LANGUAGE Sql;
All my code for inserting rows into the tables is implemented in C# using Entity Framework 4. All of the C# code is working fine. The weird thing is that when I look at the data in the Versions table, the values in the From column are all even. When I look at the sequence's properties in PgAdmin, it's odd. But the next time a row is inserted, the value stored is even.
What am I doing wrong? How does Postgres always use all of the values when you put that nextval call in the default property of a column?
Well, time for me to feel sheepish.
I looked over my C# code for inserting rows into the Versions table & I found that I was actually calling the NextVersion stored procedure twice. That explains why the sequence was always even when it was written to the From field. I've removed the second call & problem solved.
Tony
I need to duplicate selected rows with all the fields exactly same except ID ident int which is added automatically by SQL.
What is the best way to duplicate/clone record or records (up to 50)?
Is there any T-SQL functionality in MS SQL 2008 or do I need to select insert in stored procedures ?
The only way to accomplish what you want is by using Insert statements which enumerate every column except the identity column.
You can of course select multiple rows to be duplicated by using a Select statement in your Insert statements. However, I would assume that this will violate your business key (your other unique constraint on the table other than the surrogate key which you have right?) and require some other column to be altered as well.
Insert MyTable( ...
Select ...
From MyTable
Where ....
If it is a pure copy (minus the ID field) then the following will work (replace 'NameOfExistingTable' with the table you want to duplicate the rows from and optionally use the Where clause to limit the data that you wish to duplicate):
SELECT *
INTO #TempImportRowsTable
FROM (
SELECT *
FROM [NameOfExistingTable]
-- WHERE ID = 1
) AS createTable
-- If needed make other alterations to the temp table here
ALTER TABLE #TempImportRowsTable DROP COLUMN Id
INSERT INTO [NameOfExistingTable]
SELECT * FROM #TempImportRowsTable
DROP TABLE #TempImportRowsTable
If you're able to check the duplication condition as rows are inserted, you could put an INSERT trigger on the table. This would allow you to check the columns as they are inserted instead of having to select over the entire table.
Consider a trigger after update on the table A.
For every update the trigger should update all the records in table B.
Then consider this query:
UPDATE A SET X = Y
Apparently there are many rows updated. After the update the trigger takes place.
Now if the trigger would be using inserted table, and you would like to update the table B with every single row of the temporary table inserted, and in MSDN is not recommended to use cursors, how would you do that?
Thank you
I don't know what exactly you want to do in your update trigger, but you could e.g.
UPDATE dbo.B
SET someColumn = i.Anothervalue
FROM Inserted i
WHERE b.Criteria = i.Criteria
or something else - you need to tell us a bit more about what it is you want to do with table B! But it's definitely possible to update, insert into or other things, without using a cursor and handling multiple rows from the Inserted table.
I will assume that table A is related to table B via a key (have to assume, as you posted no details).
If that is the case, you can use either sub-queries or joins with inserted to select the rows that need changing on table B.
UPDATE tableB B
SET B.colx = someValue
WHERE B.id IN
(
SELECT b_id
FROM INSERTED
)