I have a stored procedure that search a view using full text.
I'm trying to map the results to an existing Entity (Sales), where I mapped the column MivType to SaleType (as it makes more sense, and I want to keep db names away from my web site). The stored procedure is mapped to a Function Import, and I've defined its ReturnType to Sales.
This work well as long as the entity has the same property names as fields names.
Here's my problem: when I change the property's name, I get the following error after running the imported function:
The data reader is incompatible with the specified 'Model.Sale'. A member of the type, 'SaleType', does not have a corresponding column in the data reader with the same name.
I can fix this if I change the property 'SaleType' to 'MivType' on the entity, but why should I do that? Isn't that what the mapping is for?
This means I have to use the exact same names on the stored procedure and the entity, so in effect, the mapping is ignored (I have names like YzrName, MivYaad, etc, and I don't like it).
Is there a simple way around this? I don't want to use the db names on my application, and prefer not to change the stored procedure...
(I should mention I'm a beginner with the EF, so this can be a rookie mistake)
Thanks.
Well the entity designer doesnt work very well. I generally try to do everything in the XML. In the XML there are 3 parts. The Storage (a representation of the SQL Database). The Conceptual (a represention of your .Net Objects. and the Conceptual to Storage Mapping
It sounds like the error is in your Conceptual to Storage Mapping. You can keep the property name SalesType on the conceptual side but the mapping must map the the correct names on both the conceptual and storage side.
Refer to MSDN here are some articles
http://msdn.microsoft.com/en-us/library/cc716731.aspx
Related
I have a problem concerning the usage of a DataTransformer.
Basically, I am developing a translation tool for my application whose goal is to be as generic as possible.
For that, I chose to follow that model : Database modeling for international and multilingual purposes
So, in different entities in my application, I have translatable attributes that simply are references to i18n elements. Then, this i18n ID is referenced in Translation table entries, that handle translation strings.
I succeed handling my translation interface, but I now have a problem with my forms : Indeed, I want some of my entities to be created/updated via forms. The problem is that I don't want the user to set a i18n ID for the translatable fields, of course, but a text, so that it can be handled by my application to either update or create the related translation in database.
I thought then that creating a DataTransformer could be a good idea, so that I can get the related translation string from the i18nID that is in my Entity entry (for that way, no problem). But my problem here is for the opposite way :
How can I deal with creating/updating i18n entries in my reverseTransform() method without knowing the entity values context?
Is there any way to get the previous entity values so that I could get the i18 ID that is stored originally in my entity? I understand that a Data Transformer is theorically totally independent from my forms and my entities, but I'm totally blocked about how to handle this case.
Indeed, when I save my entity with my translated string, I have no way to know the entity context in my reverseTransform() method, that would have permitted me to get the i18nID of the entity and to update it.
I just have the string that typed the user, but I can't do anything with that, because I can't know if it is an update or not since I don't have access to my entities.
Do you have any clue to do that? Is trying to use a DataTransformer to perform this a bad idea?
Thank you !
I'm new to MyBatis and my project requires me to read the data from the Oracle database, populate the objects, reset the data if necessary and insert it back into the database.
I'm trying to read data of a nested table. The nested table column consists of a collection of Oracle defined Custom Objects. To be more specific each record in the table is associated to a collection of Custom Object and the Custom Object consists of three fields namely nickname, date of birth and address.
I'm actually getting an oracle.sql.ARRAY data type when trying to retrieve the data. The problem I have here is that I'm not able to map this oracle.sql.ARRAY which is being fetched by the JDBC through MyBatis to my objects. All I'm able to do is get the ARRAY cast it to an object array and then to a Struct and iterate through the attributes to get the values.
I can always hand build the beans, but I know its not an efficient way of doing it. I want to configure my result map in a way that it populates my objects. But, I have not been able to do that so far. If anyone has any advice regarding this issue please help me out.
I think you can get this to work with a custom TypeHandler.
In your ResultMap, do something like this:
<result property="arrayOne" column="array[1]" typeHandler="customArrayHandler" />
<result property="arrayTwo" column="array[2]" typeHandler="customArrayHandler" />
Then in your CustomArrayHandler.getResult() implementation, you can parse the real column name and index out. Then retrieve the array from the ResultSet and get the needed value from the index.
That would require a lot of Oracle specific code in Mybatis and I know they have tried to avoid RDMS specific code in general. I would write your own data mappers to map the arrays to whatever model objects you need.
I asked a related question previously on this forum. This question outlines the steps I have taken, different things I have tried and errors I have encountered. It might help someone.
Considering a mapping to a structure that involves a link table, it seems to me there is a quirk with Code First, Link Tables and TPH or perhaps just a lack of transparency.
I created a derived class with a [Table("")] attribute to map objects to the following sort of table structures:
(Case 1) Employees -> Attributes -> AttributeTypes
(Case 2) Employees -> EmployeeAttributeLink -> Attributes -> AttributeTypes
In the former case i achieved the results i wanted for TPH querying and saving. (I used data annotation attributes along with fluent api to map the derived classes to the correct discriminator id column).
However, in the second case I got this error:
'The entity types A and B cannot share table B because they are not in the same type hierarchy [OR] do not have a valid one to one foreign key relationship with matching primary keys between them. Need to have a 1-1 correspondence'
When I looked at the names of the tables that it was trying to map types to I could see it was confused. However I could not figure out what I was doing wrong as I had used the correct table mapping attribute above the inheriting classes (I didn't define all the sub types that could come from the discriminator - does that matter?).
I introduced some FK attributes trying to address the second part of the [OR] in the error message. This led me to new problems i.e. unable to determine principal/dependant... Then I tried to use the [InverseProperty] attributes... And then I started pulling my hair out.
Now, rolling back and removing the attributes, I decided not to rely on [Table("")] attribute and map the type to the table using the fluent api. This seems to work.
My question is: Why is it that the behaviour of the [Table("") ] attribute and the ToTable function on the fluent API behave differently? I would have thought they are interchangeable
Thanks
I have a table in my SQL Server DB that holds auditing information for certain actions a user takes within my system. Things like who performed the action, when it was performed, and what action are all pieces of information that can easily span multiple actions. But depending on the action performed, there may be other information that I want to capture, that is specific to the action. To handle this, I elected to add an "XML Metadata" column to the table that holds serialized XML of different metadata objects that I've created. I created a metadata object for each of the actions that I'm interested in tracking extra for. So each object is responsible for tracking specific extra information (metadata) for it's action. The objects are serialized and written to my new column.
I have SystemAction objects that I use to store information from this table, and I've added a string field that holds the XML string from the DB. The problem is, when I'm reading this XML back from the SystemAction objects, I'm struggling with a way to generically translate it back into it's correct metadata object. Each metadata object is going to have different fields, and each object has it's own static method that takes an XML string and attempts to return the metadata object type. So I could say:
SomeActionMetadata mdObj = SomeActionMetadata.BuildFromXML(xmlStringFromDB);
But I really don't know of a way to say "Here's some XML that could translate to any number of different objects. Figure it out and give me the right object back."
Given my current implementation, I could always just assign a unique ID to each metadata object that is stored as a field in each object, then use a case statement to switch on that ID and use the appropriate class's static build method to build the right object. But I was hoping for something a little more automatic than that. What if I have a List of SystemAction objects and just want to loop through them and generate the correct metadata object type?
I was hoping someone might have run across something similar to this before, or could point me to an article or post that could help me out. Thanks very much.
As indicated by Subhash Dike in the comments below, there is a similar SO question here that was able to point me in the right direction.
Is it possible to add properties to my model that dont exist in the database?
For example I have a calendar table, I want to retireve this data in my MVC controller then work out time left until each entry starts and return this to the view. So I would like another property in my calendar model to hold time left which is a value that I will generate outside of the database.
I've tried just adding the property but when I do that I get errors because the property is not mapped to anything.
Is this even possible?
Thanks
You should be able to add the property to the Model but you will not be able to query it with LINQ. LINQ will ultimately build and expression which it will want to run against the database using SQL. Its at that point that your LINQ will fail to find a mapping from your property to a field somewhere.
If your query returns an IEnumerable of the actual type on which you have created the property your view may be able to access it. I can't remember if EF insists on mapping in that case, it may do.
You might find that you can create subsequent LINQ query that uses LINQ-to-objects if you want to provide some other composite type to your view.
It's a non-persistent property or transient. I don't know Entity Framwork well but with a quick google search you should find the answer.
BTW you can find a lot of tips here :
http://weblogs.asp.net/zeeshanhirani/archive/2008/12/18/my-christmas-present-to-the-entity-framework-community.aspx
After making a quick search myself and a test in VS2008 I don't see a way to exclude a property from the mapping. Maybe it requires you to edit manually the mapping file ? :(