I am using slick 2.1.0. Oracle doesn't have a notion of auto increment attribute for a column, so how can I manage an insert via slick using a sequence.
e.g. I have a table & sequence as follows :
CREATE TABLE USER
( "USER_ID" NUMBER NOT NULL ENABLE,
"NAME" VARCHAR2(100) NOT NULL ENABLE,
"ADDRESS" VARCHAR2(1000) NOT NULL ENABLE
);
CREATE SEQUENCE USER_ID_SEQ MINVALUE 1 MAXVALUE 99999999999999 INCREMENT BY 2;
How can I use this sequence to set my USER_ID? Also setting autoIncLastAsOption = true in Slicks's SourceCodeGenerator doesnt seem to help. My IDs are still not an Option[].
Here are some of the options suggested by Typesafe Developer:
If you don’t mind letting Slick manage the DDL, you can use O.AutoInc with OracleDriver. It will automatically create a backing sequence for the generated identity values. The way this works is by installing a trigger that automatically populates the ID from the sequence. Here’s the code that Slick generates for an AutoInc column on Oracle:
create sequence $seq start with 1 increment by 1;
create or replace trigger $trg before insert on $tab referencing new as new for each row when (new.$col is null) begin select $seq.nextval into :new.$col from sys.dual;
end;
where $seq, $trg, $col and $tab are the names of the sequence, trigger, identity column and table.
There is no special code being run during an actual insert operation. So if you already have a database schema with an identity sequence, you can manually create a trigger as shown above and mark the column as O.AutoInc in Slick to get the standard handling for auto-incrementing columns.
If you want a solution without a trigger, you could you insertExpr for inserting in Slick. This allows computed expressions, like using Slick’s own sequence API (which is supported by OracleDriver), but unlike a normal insert you do not get all features, convenience and performance (e.g. batch inserts and pre-compiled inserts).
The downside is that this can’t be precompiled (but compiling a simple expression of a few scalar values should be relatively cheap) and you can’t just insert a mapped cased class that way without some extra mapping boilerplate.
Another option would be to first get a new id (or even multiple ids for a batch insert) from the sequence with one query, put them into the data transfer objects, and then insert those normally with the ids in place. This requires one extra query per batch (for first fetching the ids) but you can easily use mapped objects and precompile everything.
Related
Using ODI 12C, I Have a dimension with a combination of 2 Primary Keys. I Just want to perform a business key with auto-increment .
NOTE : - I Don't need a SCD behavior
I did this :
1 - Create sequence in Database Schema ( with no cache )
2 - Call it in the the needed mapping :
<%=odiRef.getObjectName("L", "SEQ_NAME", "D")%>.nextval
3 - Set the mapping to be :
Active for inserts only, uncheck NOT NULL condition, EXCUTE ON HINT :TARGET
4 - PUT CKM TO : CKM SQL
5 - Run
You can create a sequence in your project or in the global objects. There are three types of it:
Standard sequence, where the last value will be stored in the repository and ODI will increment it each time it retrieves a value.
Specific sequence, same thing as above except that you choice in which table in which schema the value is stored
Native sequence, which just use an underlying database sequence. This is the most popular choice as it will be a lot better for performance.
You can then call it using :<SEQUENCE_NAME>_NEXTVAL. For a native sequence it will get a new value for each row. For a standard or specific sequence it will give a new value for each row processed by the agent. So if you do row-by-row operation, it will give a new value for each row, but if you do batch operation, it will use the same value everywhere.
You can also call it using #<SEQUENCE_NAME>_NEXTVAL but this one will be substitued only once, before pushing the SQL on the database so all rows will have the same value.
If you use a native sequence on an Oracle database, you will have to set the Execute On Hint to Target so the sequence call is in the outermost select.
is there any way to enable counting of rows that trigger modified in SQLite?
I know it is disabled https://www.sqlite.org/c3ref/changes.html and i understand why, but can i enable it somehow?
CREATE TABLE Users_data (
Id INTEGER PRIMARY KEY AUTOINCREMENT,
Deleted BOOLEAN DEFAULT (0),
Name STRING
);
CREATE VIEW Users AS
SELECT Id, Name
FROM Users_data
WHERE Deleted = 0;
CREATE TRIGGER UsersDelete2UsersData
INSTEAD OF DELETE
ON Users
FOR EACH ROW
BEGIN
UPDATE Users_data SET Deleted = 1 WHERE Id = OLD.Id;
END;
-- etc for insert & update
then delete from Users where Name like 'foo' /* doesnt even need 'Id = 1' */; works fine, but numbers of modified rows is, as documentation say, always zero.
(I cant modify my DAL to automatically add "where Deleted = 0", so backup plan is to have table Users_deleted and 'on delete' trigger on Users table without any view, but then i have to keep tracking FKs (for example, what to do when someone delete from FK table) and so on...)
Edit: Returned number is used for checking on database concurrency.
Edit2: To be more clear: As i say, I can not modify my DAL (Entity Framework 6), so the preferred answer should operate as follow pseudo code: int affectedRow = query("delete from Users where Name like 'foo';").Execute();
Its all about SQLite "trigger on view" behavior.
Use sqlite3_total_changes() instead:
This function returns the total number of rows inserted, modified or deleted by all INSERT, UPDATE or DELETE statements completed since the database connection was opened, including those executed as part of trigger programs.
Its imposible in sqlite3 (in 2015).
Basically I was looking for instead of trigger on view (as in question) with return function, which is not supported in sqlite.
By the way, postgresql (and i believe some others full db servers) can do it.
I have a single insert command which will get the records from one staging table and insert into the actual transaction table in oracle 10g. During this insertion, i want to increment one column value in transacation table irrespective of the value present in staging area.
Is there any such 'i++' kind of option available with sql programming? So that i can get the maximum value from the actual transaction table and will increment it.
Or else, any alternative way to resolve it?
You can use sequences! Read more about sequences here on Oracle documentation.
Sequences are independent database object that generate new number in a sequence specified.
E.g., if you merely say
CREATE SEQUENCE tblid_seq;
A new sequence named tblid_seq will be created, starting values from 1 and incrementing with 1.
You can use nextval and currval methods with a sequence.
E.g., everytime you use tblid_seq.nextval, you will get an incremented value.
When you use tblid_seq.currval, you will get the last value extracted by tblid_seq.nextval.
How to use it? Simple. In SQL:
INSERT INTO (tblid, val1) VALUES (tblid_seq.nextval, 'Some value');
In PL/SQL triggers, procedures, functions or anonymous block, you can use:
var1 := tblid_seq.nextval; -- var1 is of INTEGER data type.
A sequence is independent of any other database object, including the table you are using the sequence-generated value on. Sequences are also independent of transactions, you cannot ROLLBACK a sequence value. So use a sequence if you are okay with having gaps in the generated values.
I have a - for me unknown - issue and I don't know what's the logic/cause behind it. When I try to insert a record in a table I get a DB2 error saying:
[SQL0803] Duplicate key value specified: A unique index or unique constraint *N in *N
exists over one or more columns of table TABLEXXX in SCHEMAYYY. The operation cannot
be performed because one or more values would have produced a duplicate key in
the unique index or constraint.
Which is a quite clear message to me. But actually there would be no duplicate key if I inserted my new record seeing what records are already in there. When I do a SELECT COUNT(*) from SCHEMAYYY.TABLEXXX and then try to insert the record it works flawlessly.
How can it be that when performing the SELECT COUNT(*) I can suddenly insert the records? Is there some sort of index associated with it which might give issues because it is out of sync? I didn't design the data model, so I don't have deep knowledge of the system yet.
The original DB2 SQL is:
-- Generate SQL
-- Version: V6R1M0 080215
-- Generated on: 19/12/12 10:28:39
-- Relational Database: S656C89D
-- Standards Option: DB2 for i
CREATE TABLE TZVDB.PRODUCTCOSTS (
ID INTEGER GENERATED BY DEFAULT AS IDENTITY (
START WITH 1 INCREMENT BY 1
MINVALUE 1 MAXVALUE 2147483647
NO CYCLE NO ORDER
CACHE 20 )
,
PRODUCT_ID INTEGER DEFAULT NULL ,
STARTPRICE DECIMAL(7, 2) DEFAULT NULL ,
FROMDATE TIMESTAMP DEFAULT NULL ,
TILLDATE TIMESTAMP DEFAULT NULL ,
CONSTRAINT TZVDB.PRODUCTCOSTS_PK PRIMARY KEY( ID ) ) ;
ALTER TABLE TZVDB.PRODUCTCOSTS
ADD CONSTRAINT TZVDB.PRODCSTS_PRDCT_FK
FOREIGN KEY( PRODUCT_ID )
REFERENCES TZVDB.PRODUCT ( ID )
ON DELETE RESTRICT
ON UPDATE NO ACTION;
I'd like to see the statements...but since this question is a year old...I won't old my breath.
I'm thinking the problem may be the
GENERATED BY DEFAULT
And instead of passing NULL for the identity column, you're accidentally passing zero or some other duplicate value the first time around.
Either always pass NULL, pass a non-duplicate value or switch to GENERATED ALWAYS
Look at preceding messages in the joblog for specifics as to what caused this. I don't understand how the INSERT can suddenly work after the COUNT(*). Please let us know what you find.
Since it shows *N (ie n/a) as the name of the index or constraing, this suggests to me that is is not a standard DB2 object, and therefore may be a "logical file" [LF] defined with DDS rather than SQL, with a key structure different than what you were doing your COUNT(*) on.
Your shop may have better tools do view keys on dependent files, but the method below will work anywhere.
If your table might not be the actual "physical file", check this using Display File Description, DSPFD TZVDB.PRODUCTCOSTS, in a 5250 ("green screen") session.
Use the Display Database Relations command, DSPDBR TZVDB.PRODUCTCOSTS, to find what files are defined over your table. You can then DSPFD on each of these files to see the definition of the index key. Also check there that each of these indexes is maintained *IMMED, rather than *REBUILD or *DELAY. (A wild longshot guess as to a remotely possible cause of your strange anomaly.)
You will find the DB2 for i message finder here in the IBM i 7.1 Information Center or other releases
Is it a paging issue? we seem to get -0803 on inserts occasionally when a row is being held for update and it locks a page that probably contains the index that is needed for the insert? This is only a guess but it appears to me that is what is happening.
I know it is an old topic, but this is what Google shown me on the first place.
I had the same issue yesterday, causing me a lot of headache. I did the same as above, checked the table definitions, keys, existing items...
Then I found out the problem was with my INSERT statement. It was trying to insert to identical records at once, but as the constraint prevented the commit, I could not find anything in the database.
Advice: review your INSERT statement carefully! :)
I have a number of tables that use the trigger/sequence column to simulate auto_increment on their primary keys which has worked great for some time.
In order to speed the time necessary to perform regression testing against software that uses the db, I create control files using some sample data, and added running of these to the build process.
This change is causing most of the tests to crash though as the testing process installs the schema from scratch, and the sequences are returning values that already exist in the tables. Is there any way to programtically say "Update sequences to max value in column" or do I need to write out a whole script by hand that updates all these sequences, or can I/should I change the trigger that substitutes the null value for the sequence to some how check this (though I think this might cause the mutating table problem)?
You can generate a script to create the sequences with the start values you need (based on their existing values)....
SELECT 'CREATE SEQUENCE '||sequence_name||' START WITH '||last_number||';'
FROM ALL_SEQUENCES
WHERE OWNER = your_schema
(If I understand the question correctly)
Here's a simple way to update a sequence value - in this case setting the sequence to 1000 if it is currently 50:
alter sequence MYSEQUENCE increment by 950 nocache;
select MYSEQUENCE_S.nextval from dual;
alter sequence MYSEQUENCE increment by 1;
Kudos to the creators of PL/SQL Developer for including this technique in their tool.
As part of your schema rebuild, why not drop and recreate the sequence?