Oracle Trigger created using JDBC doesnt fire - java

I have created triggers over JDBC that doenot fire. I have checked its validity in the user_objects table and its valid and enabled. I tried creating trigger using the sqlplus console and it successfully fired, so where I could be going wrong? Any idea?
here is my trigger:
create or replace trigger t2
after update of FIRST_NAME on QWERTY
referencing new as newv old as oldv
for each row
begin
if :oldv.FIRST_NAME != :newv.FIRST_NAME then
insert into log values(user,sysdate,'QWERTY','FIRST_NAME',:oldv.FIRST_NAME,:newv.FIRST_NAME);
end if;
end;
I have tried execute(query) and executeUpdate(query) functions of Statement and tried PreparedStatement too but no luck yet.

You haven't considered null values in your code -- worth investigating, I'd think.

Related

Spring Boot schema.sql, initializing database using PL/SQL

I am working on a project where I have to use Oracle Database 12c and I have to write all queries manually (so I can't use Spring Data).
For creating all tables and relationships, I use schema.sql and for template data I use data.sql.
And I have a problem with checking if table or data already exists.
In MySQL creating table would be like "create table if not exists".
In PL/SQL unfortunately, there is no equivalent for "if not exists". I replaced this functionality by:
begin
execute immediate
'CREATE TABLE user_data (
some data
)';
exception when others then if SQLCODE = -955 then null; else raise; end if;
end;
And it works when I run this script in SQL Developer or in Intellij's SQL console but the problem occurs when I want to run an application and Spring Boot tries to execute a script from schema.sql.
Output in terminal tells that:
nested exception is java.sql.SQLException: ORA-06550: line 8, column 4:
PLS-00103: Encountered the symbol "end-of-file" when expecting one of the following:
* & = - + ; < / > at in is mod remainder not rem return
returning <an exponent (**)> <> or != or ~= >= <= <> and or
like like2 like4 likec between into using || multiset bulk
member submultiset
So it looks like Spring Boot doesn't know that it should run statement between "begin" and "end".
Any idea how can I manage the problem with database initialization ?
As a workaround, I could drop tables with every application run but it is not an optimal solution (and it wouldn't work when someone run the application for the first time).
Firstly, I would like to share two topics that seem to be relevant to this problem:
Unable to use "DROP TABLE IF EXISTS" in schema.sql for a Spring Boot application
executeSqlScript fails with Spring for PL/SQL block
There you will find a solution that should work: create a stored procedure and use in your schema.sql statement like
call recreate_table('USER_DATA','CREATE TABLE USER_DATA (SOME DATA)');
CALL statement is widely used across different databases, shortened to statement with only one semicolon and thus works well.
Secondly, I may only suppose, that the main problem is that anonymous blocks in PL/SQL (as well as other complex enough statements that may contain more than one semicolon) should be finished by a / character. I would recommend you to try to append this character to the end of your script, take a look at this and this answers, and if it does not work, create a stored procedure.
Also note that there is another way to check existence of the table (that comes over this wait for an exception pattern):
select count(*)
from user_tables t
where t.table_name = 'USER_DATA'
and rownum < 2

Oracle: Read-only access to the schema for another user?

I have a schema and a user with the same name: products. For development I would like to use it in a read-only mode from a java application. Therefore, I created a new user for the read-only application.
CREATE USER PRODUCTS_READONLY IDENTIFIED BY PRODUCTS_READONLY;
GRANT CREATE SESSION to PRODUCTS_READONLY;
BEGIN
FOR tab IN (SELECT table_name FROM all_tables WHERE owner = 'PRODUCTS') LOOP
EXECUTE IMMEDIATE 'GRANT SELECT ON PRODUCTS.'||tab.table_name||' TO PRODUCTS_READONLY';
END LOOP;
END;
Running the application I got the error that the table did not exist. Searching on the internet for solution, I came across SYNONYM. So I added synonym to the schema:
CREATE SYNONYM PRODUCTS_READONLY FOR PRODUCTS;
Now, I am getting this error in my java application:
ERROR org.hibernate.util.JDBCExceptionReporter - ORA-17074 invalid name pattern.: PRODUCTS_READONLY.PRODUCT_TYPE
What is wrong with my approach?
--UPDATE--
Seems like creating synonyms for schema was removed in 10g (Oracle: is it possible to create a synonym for a schema?). If I create schema for each object in the target schema, I would have to do the same every time a table is added to the target schema or any other changes to the any other objects in the target schema? That sounds cumbersome...
--UPDATE 2--
Seems like a trigger with alter session is a possible solution, but will it make the tables read-only so long the user has only SELECT privilege?
If you have control over the way your application connects (e.g. an initialization statement for your connection pool), all you need to do is run:
ALTER SESSION SET CURRENT_SCHEMA = PRODUCTS;
From that point onward (during the lifetime of the session) any unqualified object name will be searched for in the PRODUCTS schema.
All grants given to PRODUCTS_READONLY will be in effect. The session will run under the credentials (and security restrictions) of the original user used to log in.
If you can not change the way the connection is established or initialized a logon trigger should also accomplish this:
create or replace trigger logon_trg
after logon on database
begin
if (user = 'PRODUCTS_READONLY') then
execute immediate 'alter session set current_schema = products';
end if;
exception
when others then null; -- prevent a login failure due to an exception
end logon_trg;
/
Note that it's crucial to trap any exception, because otherwise a potential error in the executed SQL will effectively log everyone out off the database. So use with care and test it well before putting that into production.
I am not sure you can create a synonym for schema.
But you can create a synonym for every object in the remote schema, e.g.
begin
for c in (select t.table_name from table_privileges t where grantee = 'PRODUCTS_READONLY') loop
execute immediate 'create synonym '||c.table_name||' for PRODUCTS.'||c.table_name;
end loop;
end;
Don't be confused with table_name, it handles all types of objects there.

Before insert trigger in mysql giving issue when insert is fired from Java code

DELIMITER $$
CREATE TRIGGER `classdost`.`tr_xyz_media`
BEFORE INSERT ON classdost.xyz_media
FOR EACH ROW
BEGIN
DECLARE t_id INT(20);
IF NEW.id < 5000000 THEN
INSERT INTO xyz_media_temp (insert_date) VALUES(CURDATE());
SELECT MAX(xyz_media_temp.id) INTO t_id FROM xyz_media_temp;
SET New.id = t_id;
END IF;
END$$
DELIMITER ;
I have this trigger in MySQL this is running fine when I fire any Insert query in PHPMyadmin but when same Insert is fired from java code it is not executing. I tried changing the code made all request as Ajax with async: false and then I found out that that the earlier requests are still running in background and my later request is giving exception as no ID is returned from database yet.
What can be done to avoid this issue?
If you say requests are still running in background, then it is possible that your table is locked (MyISAM tables), and you cannot modify it.
See if table is locked using this query -
SHOW OPEN TABLES FROM database_name;
This query will show you open tables, whicj cannot be edited (INSERT, UPDATE or etc.). Then check you Java application, find code that locks tables.

Oracle Create Table if it does not exist

Can anyone point me to the right syntax to use in order to create a table only if it does not currently exist in the database?
I'm currently programming a Java GUI in order to connect to Oracle and execute statements on my database and I'm wondering if I would implement this as a Java constraint or a SQLPlus constraint.
Normally, it doesn't make a lot of sense to check whether a table exists or not because objects shouldn't be created at runtime and the application should know what objects were created at install time. If this is part of the installation, you should know what objects exist at any point in the process so you shouldn't need to check whether a table already exists.
If you really need to, however,
You can attempt to create the table and catch the `ORA-00955: name is already used by an existing object" exception.
You can query USER_TABLES (or ALL_TABLES or DBA_TABLES depending on whether you are creating objects owned by other users and your privileges in the database) to check to see whether the table already exists.
You can try to drop the table before creating it and catch the `ORA-00942: table or view does not exist" exception if it doesn't.
#Archie I would like to answer your question.
#Piyas De Sorry for stealing your code :).
Just a little update of #Piyas De answer.
BEGIN
BEGIN
EXECUTE IMMEDIATE '<<Your table creation Statement>>';
EXCEPTION
WHEN OTHERS THEN
IF SQLCODE == -955 THEN
RAISE;
END IF;
END;
END;
You can do this with the Following Procedure -
BEGIN
BEGIN
EXECUTE IMMEDIATE 'DROP TABLE <<Your Table Name>>';
EXCEPTION
WHEN OTHERS THEN
IF SQLCODE != -942 THEN
RAISE;
END IF;
END;
EXECUTE IMMEDIATE '<<Your table creation Statement>>';
END;
Hope this may help you.
try
{
// insert query for insert new record in your table
}
catch(Exception Ex)
{
//if it throw exception then catch it
int s=Ex.getErrorCode(); // check it for 903 error
//903 is table not existing error in oracle11g
// then create your new table here otherwise if table present then record get stored in database
}

Delete Stored Procedure through remote

I am creating and testing a stored procedure through remote using JUnit , my user name is test and this is my code,
String sql = "create procedure test.firstProc3 AS select GETDATE()";
cursor.execute(sql);
cursor.executeQuery("firstProc3");
ANd to drop the procedure:
String dropSQL = "DROP PROCEDURE test.firstProc3";
cursor.execute(dropSQL);
Since the Drop Procedure is not working, I am unable to run the same SP for the second time ( new session) My error is:
There is already an object named 'firstProc3' in the database.
When I gave sp_help on the server side,
the table had the row with the value
firstProc3 test stored procedure
However when I give
DROP PROCEDURE test.firstProc3 in the Query analyzer, the row is getting deleted from the table.
What could be the issue in trying to do the same operation through Junit?
Are there any permissions to be set?
PS - the user test has the db_ddladmin enabled.
I managed to finally solve the problem by using the following :
declare #object_id int
select #object_id = object_id('test.firstProc5')
EXEC sp_MSdrop_object #object_id
GO
This is removing the data from the table too.And I am able to successfully run the Testcase multiple times !
Thanks for your help :)
The link I referred to is here, hope it helps someone:
http://www.mssqlcity.com/Articles/Undoc/SQL2000UndocSP.htm
Based upon the error message, I doubt it is a permissions issue. It looks like your cursor object is running the create again when you're trying to drop, or you're never really dropping the proc before running your unit test again, or the tests are running out of logical order in some fashion. Can you instantiate a new cursor object and try the drop with that, or verify the SQL being run against the database using profiler or some debug output?
Beyond that, I would be curious to see if changing your SQL commands to check for proc existence makes the error go away (not that this is the right answer):
if object_id('test.firstProc3') is null begin
-- Dynamic SQL because create must be first in a batch
exec ('create procedure test.firstProc3 as select getdate()')
end
if object_id('test.firstProc3') is not null begin
drop procedure test.firstProc3
end
Maybe something small, and maybe it is even not the case, but have you tried to use escaping in your drop statement?
something like
drop procedure [test].[firstProc3]
I can remember that i had an issue with this when i called a drop table from c# code...

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