Informix - Foreign key constraints are dropped automatically when the reference table is altered.
There are two tables - table_main & table_reference. A column in table_main, say reference_id has foreign key constraint to a table_reference.id. These tables are created using liquibase changesets and the foreign key constraint is successfully created during table creation part.
But in future, more changesets are added to table_reference table, that alters the table schema as well. Finally after all changesets are run, when we check the constraints list on table_main, the foreign key constraint is missing. This issue is observed on Informix DB. Any idea on this, folks?
Related
I have the problem similar to this one SQL Server foreign key conflict in a multi values statement? However, in sql server 2008.
While I am reading data from csv file, there is some id already not exist in parent and thus return this error:
INSERT statement conflicted with the FOREIGN KEY constraint
May I know if there is a way similar to MySQL insert ignore. Such that I can simply skip the problematic data.
I accept that if there is no method other than creating a stored procedure with a new temp table (insert into a table without foreign key first, and then re-insert with where foreign_id exists in (select id from parent)).
As I really cannot find any in documentation, asking for ensuring I didn't miss anything.
One general solution which comes to mind would be to temporarily turn off the foreign key constraints, and do the insert. Then, afterwards, you may run a cleanup script/query to remove or rectify child records which are pointing to parents which do not exist. Once your data is in good shape, then turn on the foreign key constraints again.
Read How can foreign key constraints be temporarily disabled using T-SQL? to learn how to disable/enable a foreign key constraint for a single table:
ALTER TABLE MyTable NOCHECK CONSTRAINT MyConstraint -- disable
ALTER TABLE MyTable WITH CHECK CHECK CONSTRAINT MyConstraint -- enable
I'm using SQL Server 2008 R2 & SQL Azure database for my environment. I have defined primary keys and foreign keys and their constraint names too. I now want to change the primary key values but I cannot do it since the foreign keys not allowing me to do since they are not specified as UPDATE CASCADE when the PK-FK relationship / constraints were defined.
Is there any SQL statement by which in the existing constraints I can include the UPDATE CASCADE and henceforth change my primary key values?
As far as I know, you can only define those attributes like ON UPDATE CASCADE when you create the constraint.
So you'll need to drop the constraint and re-create it with the proper attributes.
If you need to drop the primary key constraint, you'll have to
drop all FK constraints referencing that PK
then drop and re-create your PK constraint
and in the end, re-create the dropped FK constraints
When I have SQL Server Management Studio generate a table creation script for me, the foreign key constraints are a bit different than how I would write them.
Here is one:
ALTER TABLE [dbo].[GeoBytesCountries]
WITH CHECK
ADD CONSTRAINT [FK_GeoBytesCountries_MapReferenceId]
FOREIGN KEY ([MapReferenceId])
REFERENCES [dbo].[GeoBytesMapReferences] ([MapReferenceId])
GO
ALTER TABLE [dbo].[GeoBytesCountries]
CHECK CONSTRAINT [FK_GeoBytesCountries_MapReferenceId]
GO
I would write this foreign key constraint without "WITH CHECK" and the 2nd "CHECK CONSTRAINT" statement and expect to get the same functionality.
Can someone explain to me the value of the using "WITH CHECK" and a separate "CHECK CONSTRAINT" statement when you are writing a foreign key constraint for a table?
Or is the code below completely / functionally equivalent to the code above?
ALTER TABLE [dbo].[GeoBytesCountries]
ADD CONSTRAINT [FK_GeoBytesCountries_MapReferenceId]
FOREIGN KEY ([MapReferenceId])
REFERENCES [dbo].[GeoBytesMapReferences] ([MapReferenceId])
GO
The way I see it, the two step approach allows you to at least keep more "bad" data from getting in assuming the with check part fails. That is, your constraint will exist and apply to DML from that point forward, but you may have to do some cleanup on your existing data to make it a trusted constraint.
I have inherited an old database which wasn't designed very well. It is a Sql Server 2008 database which is missing quite a lot of Foreign Key relationships. Below shows two of the tables, and I am trying to manually create a FK relationship between dbo.app_status.status_id and dbo.app_additional_info.application_id
I am using SQL Server Management Studio when trying to create the relationship using the query below
USE myDatabase;
GO ALTER TABLE dbo.app_additional_info
ADD CONSTRAINT FK_AddInfo_AppStatus FOREIGN KEY (application_id)
REFERENCES dbo.app_status (status_id)
ON DELETE CASCADE
ON UPDATE CASCADE ;
GO
However, I receive this error when I run the query
The ALTER TABLE statement conflicted with the FOREIGN KEY constraint
"FK_AddInfo_AppStatus". The conflict occurred in database
"myDatabase", table "dbo.app_status", column 'status_id'.
I am wondering if the query is failing because each table already contains approximately 130,000 records?
Please help.
Thanks.
The error is occuring because there is a value in dbo.app_additional_info.application_ID that is not in dbo.app_Status.Status_ID. Unless the naming convention is seriously messed up you are trying to add a relationship to unrelated columns, why would application_ID reference status_ID?
I expect that dbo.App_Additional_Info.Application_ID should be referencing dbo.Application.Application_ID (Guessing at the table and column names slightly) so you would want this:
USE MyDatabase
GO
ALTER TABLE dbo.App_Additional_Info
ADD CONSTRAINT FK_App_Additional_Info_Application_ID (Application_ID)
REFERENCES dbo.Application (Application_ID)
ON DELETE CASCADE
ON UPDATE CASCADE;
I had to modify an existing constraint so it would cascade updates and deletes.
To do this I first removed the constraint and was planning on adding it (through an ALTER TABLE) but this fails.
When I commit the query below it gives me the error 'ORA-01735: invalid ALTER TABLE option':
ALTER TABLE
PARAM
ADD CONSTRAINT
FK_PARAM_PORTLET FOREIGN KEY (PORTLETID)
REFERENCES PORTLET(ID)
ON DELETE CASCADE ON UPDATE CASCADE;
Any idea what it could be? Am I overlooking something?
Oracle does not support ON UPDATE CASCADE in foreign keys.
Have a look at this question for tips: How to create a Foreign Key with "ON UPDATE CASCADE" on Oracle?
UPDATE CASCADE is not supported in Oracle. You will need to manage this via triggers.
Check Oracle statement:
Referential integrity constraints can specify particular actions to be
performed on the dependent rows in a child table if a referenced
parent key value is modified. The referential actions supported by the
FOREIGN KEY integrity constraints of Oracle are UPDATE and DELETE NO
ACTION, and DELETE CASCADE.