I am trying to create a model in my module that saves data and links against the customer_entity table. I have got the module saving the model without the foreign key constraint but as soon as I alter the table to include the constraint I get an integrity constraint violation exception even though I am including a customer id that exists in the customer_entity table.
Is there something extra I need to do with my model class or model resource class to get the model saving correctly?
There's too many things that could be a mitigating factor here. At some point Magento is running some set of SQL queries that temporarily (or possibly permanently) cause a foreign key constraint. The only way to solve this is to drop down below the Model layer and look at the actual SQL being run against your database.
Related
parcel table
$table->unsignedBigInteger('shop_id');
$table->foreign('shop_id')->references('id')->on('shops');
** I have a model name Shop I want to add its is to id as a foreign key to parcel table **
I think that the problem lies in the order you created your migrations. Look at the order and make sure that shops table comes before the parcels table. If this is not the case, then the easiest way would be to change the table times e.g. date_time_name. Change time and you'll be set.
I apologize if I repeat the question, but I did not find a similar one.
I have added a unique constraint on an already existent table. We use MariaDB.
I have used the annotation:
#Table(uniqueConstraints={#UniqueConstraint(name="autonomy_name_energyType", columnNames={"autonomy","name","energyType"})})
The unit tests pass, but in the DB I am still allowed to create duplicates.
Do I need an ALTER table too? By checking the table I can see there are no constraints added to it.
Thanks
As explained in these SO posts :
Unique constraint not created in JPA
#Column(unique=true) does not seem to work
An explicit alter table query is needed for ur constaints to take effect on the db level.
As an extra info, it would have worked if the table was being re-created via JPA. see :
Add a unique constraint over muliple reference columns
The diagram has over 40 tables, most of them have a primary key defined.
For some reason there is this one table, which has a primary key defined, but that's being ignored when I export the model to a DDL script.
This is the "offending" key (even though it's checked it is nowhere to be found on the generated DDL script):
Has anybody had the same problem? Any ideas on how to solve it?
[EDIT] This is where the key is defined:
And this is the DDL preview (yes, the primary key shows up there):
This is what happens if I try to generate the DDL for just that table (primary key still not generated):
I was finally able to identify and reproduce the problem.
It was a simple conflict of constraints.
Table MIEMBROS had a mandatory 1 to n relationship (foreign key) from another table on its primary key column and vice-versa (there was a foreign key on MIEMBROS against the other table's primary key).
This kind of relationship between two tables makes it impossible to add a record to any of them: The insert operation will return an error complaining about the foreign key restriction pointing the other table.
Anyway I realized that one of the relationships was 0 to n so I simply unchecked the "mandatory" checkbox on the foreign key definition and everything went fine.
So, in a nutshell: The Data Modeler "fails" silently if you are defining a mutual relationship (two foreign keys, one on each table against the other table) on non nullable unique columns, by not generating the primary key of one of the tables.
Such an odd behavior, if you ask me!
"This kind of relationship between two tables makes it impossible to add a record to any of them: The insert operation will return an error complaining about the foreign key restriction pointing the other table."
Actually, if you have deferred constraints, this is not impossible. The constraints can be enforced, for example, at commit time rather than immediately at insert time.
From the Data Modeler menu under File, I used Export -> DDL File. The keys appeared in the DDL, then when I went back to the diagram and did DDL Preview, it showed all the missing stuff.
The design of my database has a table named person and tables employee and student are specializations of the table person the relationship between tables is total and has an overlapping restriction.
The problem is that I want to insert a student or employee and that the parent table (person) is updated automatically but the DBMS says violated a referential integrity constraint
I am using oracle can someone help me?
If I understood you correctly you have one table per type (TPT) and an employee can never be a student and also the other way around.
I assume that your problem is that the constraint is checked immediately instead of using deferred checking. That means the constraints are checked when your transaction is finished - which gives you the possibility to insert an employee/student and let your trigger do its work and after that do the commit.
Information about deferred constraints:
Oracle documentation
More information
I have 2 tables in my database that I'm trying to create Linq2Sql entities for. There's more to them than this, but this is essentially what they come down to:
Rooms UserActivity
-------- --------
RoomID ActivityID
RoomID (foreign key on Rooms.RoomID)
The UserActivity table is essentially just a log for actions a user performs against the Rooms table.
Since the UserActivity table is only used for logging actions taken, it didn't make a lot of sense (to me at least) to create a primary key for the table originally, until the Linq2Sql mapper refused to make UserActivity a part of the Room entity in my Linq entities. When I set up the entities in the Visual Studio designer, I got these 2 warnings:
Warning 1 DBML1062: The Type attribute 'UserActivity' of the Association element 'Room_UserActivity' of the Type element 'Room' does not have a primary key. No code will be generated for the association.
Warning 2 DBML1011: The Type element 'UserActivity' contains the Association element 'Room_UserActivity' but does not have a primary key. No code will be generated for the association.
These warnings led me to create the ActivityID column in my table as displayed above.
What I'd like to know is if there is any way to allow Linq2Sql to create relationships between my entities without having a primary key in both tables. If I don't have the primary key in the UserActivity table, the entities can still be created, but the relationships aren't generated.
Is is it possible to do this, or should I try to make sure my tables always have a primary key in them as a general good practice?
Any table that stores real data in your app should always have a primary key - most cases, in SQL Server environments, a INT IDENTITY(1,1) will be just fine. You don't have to keep track of those, no bookkeeping necessary etc. It doesn't cost you much, totally easy to do - I don't see any reason why not have a primary key, even on your UserActivity table.
ALTER TABLE UserActivity
ADD UserActivityID INT IDENTITY(1,1)
CONSTRAINT PK_UserActivity PRIMARY KEY
and you're done!
The only time I would say no primary key is needed is for things like temporary tables when bulk importing huge amounts of data, or other temporary scenarios.
Marc
You need a primary key to create relationships.
It's good practise to always design tables with primary keys, even if you add surrogate (auto increment identity).