I've looked at lots of other questions on SO but can't get the answer. I have a column in a table called: Sex - Male
I would like to get my hands on whoever named it as it's giving me problems with EF. If I use this:
[Column("Sex - Male")]
public bool Sex { get;set; }
This gives me the error of being incompatible with the model as the field "Sex" could not be found. So I changed to this:
[Column("[Sex - Male]")]
public bool Sex { get;set; }
I then get the message Invalid Column Name [Sex - Male]. Does EF rename columns with spaces in some way as the field does exist and is not any kind of FK?
EDIT
I have found that doing this in the modelBuilder:
modelBuilder.Entity<Student>().Property(x => x.Sex).HasColumnName("Sex - Male");
Causes the same error to appear saying it's incompatible as there is no column called Sex with the same name! I've noticed it occurs on anything I use the Column data annotation for not just this field!
EDIT 2
I created a new application and used a Model Designer to see how it interpreted the column and showed it in the designer as "Sex___Male", however, changing the class to this even with []'s around it still gives me could not find column Sex___Male??
EDIT 3
It appears the error isn't quite what I thought, I found the mapping config works fine when I just use db.Students; and the column is there as expected.
It turns out the area going wrong is this line:
var students = (db as IObjectContextAdapter).ObjectContext.ExecuteStoreQuery<Student>(sql);
So it's clearly the ExecuteStoreQuery that I'm guessing won't use the same mapping configuration therefore sees the column as missing. Not sure why putting the Column annotation on the property in the class doesn't work though??
I have recreated your situation in a test configuration. I was able to succesfully insert and query data using the following configuration
SQL Server 2012
Visual Studio 2013
Entity Framework 6.0.1
If you are using an older version of Entity Framework I would consider updating; that's most likely the cause, however I'm not able to reproduce your environment so this answer is only a guess. I used this code:
Created a table:
create table MyTable2 (
[pk] int not null identity primary key,
[Sex - Male] bit not null);
Class:
public class MyTable2
{
public int pk { get; set; }
public bool Sex { get; set; }
}
Mapping configuration:
this.HasKey(t => t.pk);
this.Property(t => t.Sex).HasColumnName("Sex - Male");
It appears that Entity Framework itself had no issue mapping this column regarding it's normal use however the issue I had is where I was using the ExecuteStoreQuery method to map the model.
It turns out using this means anything you map it to has to have the same names regardless of any data annotations you add on for column (they appear to just get ignored). What I did instead was make a small class with just the fields I needed and changed the sql of the query to Select StudentID As ID, [Sex - Male] As Sex, ...other fields FROM ...etc i.e.
public class StudentReadOnly
{
public int ID { get; set; }
public bool Sex { get;set; }
... other properties
}
And then changed line to:
var students = (db as IObjectContextAdapter).ObjectContext.ExecuteStoreQuery<StudentReadOnly>(sql);
And had no problems. I also found that any properties you put in the class MUST exist in the sql query unlike a usual ef query.
Related
I have a .Net6 WinForms application using Entity Framework Core 6.0.3 and I am trying to read a simple table from a SQL Server database. I need to rename the column so that it is different in the model than what it is called in the database.
Normally (in EF6, I would add a [Column()] attribute on the property with the new name. However, when I do that it throws an exception reading the data 'Invalid column name' for whatever the new name is.
I have also tried using the modelBuilder and calling the HasColumnName() but get the same error. If I remove the attribute/model builder reference, then no exception occurs, except that I am stuck with the old column name.
[Table("RefTable1")
public partial class SpecialReferenceTable
{
public Int32 Id { get; set;}
[MaxLength(300)]
[Column("NewRefColumn"] // Throws exception Column does not exist: NewRefColumn
public String? OldRefColumn {get;set;}
}
Is there something I am missing with renaming column in Core?
[Column("Column name")] is used for the name of the column in the database table and the name of the property you have is the one you want to change.
I used EF6 Database First tools to generate C# classes for 2 tables from my database, then (as advised in the blog post that helped me through the steps to do that) copied the resulting .cs files into a new project. I made a few edits to the classes to support sensible names in my C# code. Here's a snippet of one of the classes with "LongTableName" replacing a strangely long name used in the database.
namespace RidesData
{
[Table("LongTableName")]
public partial class PhoneData
{
[Key]
[Column("LongTableNameID")]
[DatabaseGenerated(DatabaseGeneratedOption.Identity)]
public int ID { get; set; }
[Column("LongTableNameAccountID")]
public int AccountID { get; set; }
// more fields
}
}
I am not in control of the table names, nor the fact that the many of the column names have the table name as prefixes. But the Code First ideas in EF6 should, I thought, let me use reasonable class and field names despite that. (The Database First code generator did a good job of adding code to OnModelCreating to specify that none of the columns corresponding to C# string data used Unicode.)
My model (generated by the EF6 tools and that inherits from DbContext) includes (after some renaming by me)
public virtual DbSet<PhoneData> PhoneRecs { get; set; }
and I thought all would be fine when I created an instance of PhoneData, populated it, and did
Model.PhoneRecs.Add(phoneData);
but the first thing that happened when I ran the code -- well before any call to SaveChanges() -- was that EF generated CREATE TABLE statements for the two tables; the table corresponding to the snippet above was named PhoneDatas (not using the specified table name) and the column names were the same as the field names in the class (not what was specified in the Column(...) attributes).
Of course the table I had specified did not need to be created. EF just had to grok that I wanted to use the table and column names I had specified via attributes.
I did not expect this failure of explicit Code First attributes. Does anyone have a clue why this isn't doing what I want, or how to fix it? (Do I have to do something to specify the table & column names in OnModelCreating as well as -- or instead of -- the attributes?)
Note that the project that I copied these classes into had never "seen" the database before. There are no vestiges of any "models" left over from tooling having looked at the database. Also, I hope it does not matter that I've tried to keep things on .Net 4.0 (avoiding going to 4.5 in this code).
Any assistance would be appreciated.
I'm not a big fan of DataAnotations either. Use EntityTypeConfiguration. It gives you the naming flexibility I think you are looking for.
Example.
public class PhoneData
{
public int ID {get;set;}
public string SomeProperty {get;set;}
}
public class PhoneDataMap : EntityTypeConfiguration<PhoneData>
{
public PhoneDataMap()
{
ToTable("WhatEverYou_Want_to_call_this");
HasKey(m => m.Id);
Property(m => m.SomeProperty).HasColumnName("whatever").IsRequired();
//etc.
}
}
Then in your on ModelCreating you add
modelBuilder.Configuration.Add(new PhoneDataMap());
On a side note, if you are having trouble with pluralization of your table names you can add this to OnModelCreating as well
modelBuilder.Conventions.Remove<PluralizingTableNameConvention>();
-----edit-----
I have my code working now. I tried making the relationship one-to-many and it works now by using:
newInspection.Sites.Add(newSite)
The Unique Key constraint is still present in the database, so I'm not completely comfortable with this as being the "answer" since it's more of a work around. I have no idea how to make the one-to-one work, as every time I have tried it (with other tables too for testing purposes) it always gives me this error.
----/edit-----
I am using EF 6 Code First for an application I am developing. I used the EF 6.1 tools to reverse engineer the code first model. I am running into a problem with a 1-to-1 relationship when trying to add new items to the database.
Here is the object that's causing a problem:
[Table("childTable")]
public partial class Site
{
[Key]
public int siteID{ get; set; }
public int inspectionID { get; set; }
...
public virtual Inspection inspection { get; set; }
}
The main "inspection" class has a 1-to-1 relationship with the site, and the class is organized like this:
[Table("someTable")]
public partial class Inspection
{
[Key]
public int inspectionID { get; set; }
...
public virtual Site site { get; set; }
}
The context defines this:
modelBuilder.Entity<Inspection>()
.HasOptional(e => e.site)
.WithRequired(e => e.inspection);
I am creating a new "Site" object and setting everything in it except the "siteID" and "inspectionID" properies -- the primary and foreign key respectively. I am adding it to a new "Inspection" object as a navigation property, then adding the "Inspection" to the context and trying to save:
Inspection newInspection = new Inspection
{
...
site = newSite; // Constructed earlier, no explicit ID. ID = 0 if checked
};
using (var db = new Context())
{
db.Inspections.Add(newInspection);
db.SaveChanges();
}
When I call the SaveChanges() I get the "Cannot insert explicit value for identity column in table '--------' when IDENTITY_INSERT is set to OFF."
I cannot understand why it is doing this, so I used db.Database.Log to check out the SQL being generated, and it is trying to pass an ID for the siteID after the "Inspection" insert. That doesn't make sense to me, because if I check the siteID before calling SaveChanges() the ID is 0, as a "new" one should be. However, it is actually trying to insert a number, like 16. I am unsure where it is getting the number. I thought when adding a new item to the context (i.e. db.Inspections.Add()) that it flagged everything in there as new and treated it as such during insert.
I have no idea why it is trying to insert the ID, but it appears to do this for any navigation property that is 1-to-1. That requires setting the navigation property explicitly, as opposed to using the .Add() method. 1-to-many have always worked fine for me (and do in this Context).
Does anyone know why my DBContext is trying to pass the ID?
Entities that have a 1 to 1 relationship should have the same value in the primary key. That means that the primary key in the dependent should also be a foreign key to the principal, and should not be an identity field.
You should change your tables in line with that requirement so that EF can insert the Inspection object then take its new ID and insert that value into the Sites table as the foreign key/primary key.
EF will add the foreign key constraint when you migrate back to a one-to-one but you will need to add sql to the migration to remove the Identity because EF can't do that (yet)
References:
What does principal end of an association means in 1:1 relationship in Entity framework
Do I define a relationship between two entities on the dependent or the principal?
Configuring a Required-to-Optional Relationship (One-to-Zero-or-One)
I'm testing out scaffolding with Entity Framework in Asp.Net MVC 4 (by following this article). I get it to work fine, except that even though my domain object allows null in a field and the database field allows null I get the error message:
Cannot insert the value NULL into column 'IsSuccessful', table 'MyTestProject.Persistence.TestContext.dbo.Prediction'; column does not allow nulls. UPDATE fails.
The statement has been terminated.
My domain object looks like this:
public class Prediction
{
[Key]
public int Id { get; set; }
[Required]
public string Title { get; set; }
[Required]
public string Description { get; set; }
public bool? IsSuccessful { get; set; }
}
The generated web page shows IsSuccessful as a drop down box with the choices NotSet, True and False. In the database the column IsSuccessful allows null. Still I get the error message. Everything works fine if I choose True or False (it is saved correctly in the database), but not when I select NotSet.
Surely there must be a way around this?
Some details:
Visual Studio 2012 RC
Asp.Net MVC 4
EntityFramework.dll version 5.0.0.0
That error message looks like it is coming directly from SQL Server. If the server says the column is not nullable, then the column is not nullable. It knows best, after all.
Treble check that the column is really nullable in the database. Also consider:
are you perhaps looking at a different database, with slightly different schema? i.e. one that has not had the correct DDL scripts applied (really easily done)
are you perhaps looking at a different object in the same database? In particular, are you perhaps looking at Halvard.Prediction, where-as the code is looking at dbo.Prediction ?
We are trying to get Entity framework working at our shop with an existing database (and therefore, changing the database schema is NOT an option), and the unit tests we created to test things are showing some really strange behavior.
This is the SQL it spits out for a specific object we have:
SELECT
[Extent1].[CommentTypeId] AS [CommentTypeId],
[Extent1].[DataPartId] AS [DataPartId],
[Extent1].[CommentId] AS [CommentId],
[Extent1].[CreatedTime] AS [CreatedTime],
[Extent1].[Message] AS [Message],
[Extent1].[From] AS [From],
[Extent1].[Likes] AS [Likes],
[Extent1].[SourceTypeId] AS [SourceTypeId],
[Extent1].[StatusMessage_DataPartId] AS [StatusMessage_DataPartId],
[Extent1].[Album_DataPartId] AS [Album_DataPartId]
FROM [dbo].[Comments] AS [Extent1]
The last two columns requested, as you might notice, are not like the others. That's because they don't actually exist, and we have no idea why Entity is requesting them! Neither our configuration files nor our POCOs make any mention of them at all. In fact, as far as our database goes, they're completely separate concepts and aren't directly related at all.
Where is it getting these columns from, and how do I tell it to cut it out?
EDIT: To respond to some of the questions below,
1) We are using Entity Framework 4.2. We are using fluent mapping.
2) The POCO itself looks like this, with the equality mess cut out for the sake of brevity:
public long DataPartId { get; set; }
public string CommentId { get; set; }
public DateTime? CreatedTime { get; set; }
public string Message { get; set; }
public string From { get; set; }
public int? Likes { get; set; }
public string SourceTypeId { get; set; }
public int CommentTypeId { get; set; }
public virtual DataPart DataPart { get; set; }
public virtual CommentType CommentType { get; set; }
3) We are not using edmx. We have a custom DbContext. There are not too many lines that are terribly interesting. These two are probably of interest:
Configuration.LazyLoadingEnabled = true;
Configuration.ProxyCreationEnabled = true;
Beyond that, the Context file is a lot of
modelBuilder.Configurations.Add(new WhateverConfiguration())
and
public IDbSet<WhateverPoco> PocoDatabaseTableAccessor { get; set; }
4) We started with db-first, but that didn't work, so we're currently doing code-first.
5) This is the guts of the config for that specific POCO:
HasRequired (x => x.DataPart)
.WithRequiredDependent (x => x.Comment);
HasRequired (x => x.CommentType)
.WithMany (x => x.Comments)
.HasForeignKey (x => x.CommentTypeId);
HasKey (x => x.DataPartId);
ToTable ("Comments", "dbo");
The problem is not in the mapping or class you showed. Check your Album and StatusMessage classes. Are they entities? Are they mapped? Do they have collection navigation properties to comments? If yes EF expects that Comment must have FK to these tables. If the table doesn't have such column you cannot have these navigation properties mapped in those entities.
Btw. Shouldn't the id in Comments table be CommentId instead of DataPartId?
Entity Framework, like MVC, uses a lot of convention over configuration. That means it assumes certain things unless you tell it not to.
However, something is really strange here based on the information you supplied. According to the SQL query, this is coming from the Comments table, however your fluent mapping says that DataPartId is the primary key. Do you have additional primary key fluent mappings? If not, your mappings may be wrong. Have you checked the actual database generated to see if the data model matches what you are trying to do?
My guess is that your StatusMessage and Album classes have navigational properties to Comment, but since you have only defined DataPartId as your primary key, that is the value it is using to look up the comments, not CommentId.
Open the .edmx in a XML-Editor and search for these columns. They must be somewhere in your model.
EDIT: your original question didn't mention that you are using code first. I wonder what your trouble was with Database first, that usually works fine well. With code first or model first, you normally create the database after creating the model (using generated SQL scripts).
You declared the last two properties as virtual, that's why the generated SQL looks different. From the code you are showing us we cannot see where the reference to Album comes from.
Because you have the database, I would generate the .edmx from the model in one project. Then you can use a POCO code generator or a Self-tracking entity generator to generate the entities and store them in a different project. Or you can write them manually as you already have. The property names must correspond with the columns in the database.