I have renamed a property of one of my models from CompanyId to CustomerId. I went into the database and renamed the column there as well.
I'm getting an error that 'CompanyId is an invalid column name'. This old column name is no longer referenced anywhere in my code, so I don't know where this is coming from.
If I rename the column in the database back to CompanyId, and keep the property name still as CustomerId, it then gives me an error that 'CustomerId is an invalid column name.'. So it knows that the column should be called CustomerId, but when I change the column name in the DB to CustomerId, then it complains the old column name doesn't exist.
I'm not using the built in EF Migration, I have a separate SQL Database project that I'm using to manage the schema outside of ABP. Is there some kind of cache somewhere that is keeping track of the properties/columns/etc?
solved:
This Entity Framework Core still picks up old column did the trick. It turned out Entity Framework Shadow Properties were the issue. I had another class that had a collection of Companies so it had expected this class had a CompanyId on it.
This Entity Framework Core still picks up old column did the trick. It turned out Entity Framework Shadow Properties were the issue. I had another class that had a collection of Companies so it had expected this class had a CompanyId on it.
Related
I'm facing a problem with duplicate records in a MySQL database when I'm upserting using JpaRepository.saveAll() entities which are already present in the database. I want new entities to be inserted, existing ones to be updated(if there are changes to any of the properties), otherwise no action is expected.
The entity classes id property is annotated with #GeneratedValue(GenerationType.IDENTITY) and the id column in the corresponding table in MySQL has auto-increment enabled. I'm pointing that out because JpaRepository.save(), which is invoked for each entity in saveAll(), does a check by id if the entity is already present in the database.
Here is where in my opinion the contradiction between save(), when used for updating, and auto-generation of IDs occurs: You can't update existing records because all of the entities passed into saveAll() will have newly generated IDs and thus the check in save() will always say that they are not present in the database.
Is my logic correct?
The only solution to the problem that I can think of is to create a custom query that compares the records in the database with the newly passed entities by the values of another column whose values are unique. I can't compare them by id because I will encounter the same problem as in save().
Is that good enough and are there any other solutions?
Depending how you look at it, your are either wrong or right.
What you describe in terms of behaviour is correct: If you pass in an entity with id set to null to save you will always create a new row in the database and never perform an update. In that sense you are correct. That behaviour is independent of how the id gets generated for new entities.
But the id of an entity defines its identity. If two entities have the same id they represent the same row in the database thus the same logical entity and the behaviour of save is exactly that of an upsert. This is also independent of how the id gets generated for new entities.
If you want an upsert based on a different column (or columns) you need to write custom code, for example using an actual upsert statement in a query annotation. Alternatively you can try to load the entity by the columns in question and if you succeed set its values as desired and otherwise create a new entity and save that.
I want to have a form where I can add new fields (columns) in an specific entity. Is there a function for this?
Kind regards
Adding a whole column to the table through an HTML form is a weird use case.
If you want to stick to the ORM way of managing the persisted data, you'll have to dynamically add properties to existing entities, which might be a sign of bad schema design.
What I would guess you probably need is an automated way to add this column to your Entity. In such a case I would use the maker bundle.
Supposing that your Entity is called Employee, all you have to do is to type in the following command:
bin/console make:entity
When you'll be asked for the Entity name, enter Employee. The interpreter will tell you that this entity exists and if you want to extend it with news fields, and there you go.
I am working on a project that is an upgrade of an existing system.
The existing DB structure must be kept intact as there is a system reading the same DB that will be used ontop of the new system.
I am building a new CMS / Management system using a PHP framework that expects so see all DB table autoincrement ID field named simply "id" - I do not want to modify the PHP deal with anything other that "id" as this field name - trust me it will be a massive task.
The existing DB has non standard Autoincrement ID field naming, eg:
"iBmsId" -shcema: i=INT Bms = the name of the table, Id = ID....
Is there anything I can do to the DB itself to make a duplicate of the "iBmsId" column, to create a matched column called simply "id" that has the corresponding INT values? This way my new system will function as expected without having to do a serious re-write, and at the same time still have the existing system able to communicate with the DB?
In this situation you can just use VIEW :)
http://dev.mysql.com/doc/refman/5.0/en/create-view.html
View in dbms is like a virtual table (unless it's materialized). Views add a new abstraction layer which can support independency between how you use db and how it's implemented. It can also increase security for example by hiding some fields or making view readonly.
Notice: In order to add view transparently you can rename origin table and create the View with origin table name. This let's you avoid modifications in existing code.
You can read here how to create updatable and insertable view (which can behave as normal table).
If only one system at a time is modifying the value, then you can use a view:
create view v_table as
select t.*, iBMid as id
from table t;
Presumably, an auto-incremented value is not going to be updated, so this should be safe. However, keep in mind that:
To be more specific, a view is not updatable if it contains any of the following:
. . .
Multiple references to any column of a base table.
This could affect other columns that you might want to treat the same way.
I want to use the EF (4.2) in the following scenario:
There exists a database already (so I chose the database-first approach) and it is a SQL Anywhere DB.
I want to use persistence-ignorant business objects, so I use the DbContext Template to generate POCO classes from the EDM.
There is one simple inheritance hierarchy among my entities: an abstract base entity and two concrete derived entities.
In the database there is one table for each type of the inheritance hierarchy (Table-Per-Type Strategy).
Each of these three tables has a primary key column (Id, type:integer), and the association of a concrete entity to the base entity is done by having the same Id in both tables (that means that the primary key (Id) of the concrete type tables is at the same time a foreign key to the base table; a pretty common approach I think).
I had to define the Inheritance manually in the designer, since the EDM assistant does not automatically recognize, that is want to have an inheritance association between the described entities.
Until this point there wasn't any bigger problem. Now to the issue at hand:
There is a restriction for the database I use: Primarykey values have to be generated by the database, using a database function.
I want to call this function in a before-insert-trigger defined on the base-table.
To let the entity framework know that a value is generated by the database, I set the StoreGeneratedPattern property of the Id Property of the base-entity to Identity (As I understood, this is the way to tell EF to get the generated value after inserting a new instance of an entity).
When I create a new instance of a derived entity, add it to the corresponding DbSet of the DbContext and call SaveChanges on the context, a DbUpdateException is thrown, stating that a foreignkey constraint is violated.
By checking the request-log of the DB, I see that the base entity got inserted in the base table, but on inserting the row in the derived table, the above mentioned error occurs, because it obviously doesn't use the newly generated Id of the new entry in the base table.
Since I don't think there is much I can do on a database level against that, the question is, if the EDM or DbContext can be configured (or modified) to insert the base row first, then take the generated Id and use it for insertion of the derived row.
I know there are several way to avoid this situation (not using inheritance, using a stored procedure to insert a new derived entity, calling the id-generating db-function before inserting and set the Id property myself on the entity), but at the moment the above-described behavior would be the most preferable, so I want to make sure not to overlook something before deciding for any "plan B".
Any suggestions on this topic are much appreciated,
Thanks in advance.
Here is the code of the trigger:
ALTER TRIGGER "TRG_GENERATE_ID" before insert order 1 on
BASE_TABLE
referencing new as NewEntry
for each row
begin
declare NewID integer;
set NewID = F_GET_NEW_ID('BASE_TABLE', NewEntry.SOME_OTHER_ID);
set NewEntry.ID = NewID
end
The function "F_GET_NEW_ID" is called in the trigger to generate the new ID for a new entry in the base table. It has two parameters:
"Tablename" -> The name of the table for which a new ID should be generated,
and a second parameter that takes the value of a standardcolumn in all tables of the database (it is required to generate the new ID).
I am using ASP.NET MVC2 on top of a MySQL database in VS2008. I am using the MySQL ADO.NET connector 6.2.3 to provide the connection for the ADO.NET Entity Data Model.
This is mostly working ok, however navigating via foreign keys is causing me a real headache!
Here is a simplified example..
Car (Table)
CarID PK
Colour
Doors
ManufacturerID FK
Manufacturer (Table)
ManufacturerID PK
Name
In the edmx file I can see the 1-many relationship shown as a navigation property in the both the Car and Manufacturer tables. I create a Models.CarRepository that allows me to returns a IQueryable.
At the View I want to be able to display the Manufacturer.Name for each car. This is not accessible via the object I get returned.
What is best way to implement this? Have I encountered a limitation of the Entity Framework/MySQL combination?
Eager loading of the related records needs to be enabled in the Model Repository. Something like:
var allCars = from c in automobileEntites.Car.Include("Manufacturer")
select c;
This then makes the related records available for subsequent query/display.