I'm attempting to use the timestamp[] field type in Postgres with NPGSQL, so that I can use the DateTime[] type in my Entity Framework models.
I've added this to my EF code first model.
[Column("HostUnavailableDates", TypeName = "timestamp[]")]
public DateTime[] HostUnavailableDates { get; set; }
I've created a migration and the database has updated successfully.
However I am getting this error when executing transactions with the model.
Message: System.InvalidOperationException : The property 'HostApplication.HostUnavailableDates' could not be mapped, because it is of type 'DateTime[]' which is not a supported primitive type or a valid entity type. Either explicitly map this property, or ignore it using the '[NotMapped]' attribute or by using 'EntityTypeBuilder.Ignore' in 'OnModelCreating'.
I've followed this answer which does not use any type of ignoring of the property. Is there something I need to do for the DateTime type in addition to what I'm currently doing?
Is DateTime in fact not supported at all in this case?
I'm using EF Core.
I'm assuming you're using Entity Framework 6.x. If that's the case, then arrays simply aren't supported, you'll have to switch to Entity Framework Core.
Related
I am using Entity Framework Core 7.0.0 and in my OnModelCreating method I am trying to specify a column to be of type nvarchar(max).
In EF6 (not Core!), we were able to do something like:
modelBuilder.Entity<Log>().Property(p => p.Errors).IsMaxLength();
However, I am not able to figure this out in EF Core. Is there something similar available in EF Core that I am missing?
I know that it would normally default all properties of type string to nvarchar(max) but I am overriding DbContext's ConfigureConventions with the following, to default all string to 50 characters:
configurationBuilder.Properties<string>().HaveMaxLength(50);
With help of [Column] data annotation:
[Column(TypeName = "nvarchar(MAX)")]
With help of Fluent API:
entity.Property(p => p.Errors)
.HasColumnName("YourColumnName")
.HasColumnType("nvarchar(MAX)");
HasColumnName: the HasColumnName attribute is applied to a property to specify the database column that the property should map to when the entity's property name and the database column name differ.
HasColumnType: the HasColumnType method is applied to a property to specify the data type of the column that the property should map to when the type differs from convention.
I'm wondering if there is any way to map a stored procedure result into into a class.
This is what I have:
// DbContext Class:
public DbSet<StoredProcedureModelResult> SPMR { get; set; }
// Service Class:
var result = ctx.Set<StoredProcedureModelResult>().FromSql("getXXXX p1 = {0},1).ToList();
This works well, however, I'm using database migrations and every time I add one this thing creates StoredProcedureModelResult as a table...
I tried to ignore it onModelCreating:
modelBuilder.Ignore<SPModels.test>();
but this throws an exception:
Cannot create a DbSet for 'StoredProcedureModelResult ' because this type is not included in the model for the context
I just want use the benefit of mapping, and not to get a table creation, this is a simple model (non-entityType)
BTW
.NET Core 1.1
Web API
EF Core (code-first)
Thank you
You don't need to make the type an Entity type (by registering a DbSet in your DbContext). Just have a method that returns IEnumerable<StoredProcResults> (can be in your DbContext), and in it run
dbContext.Database.SqlQuery<StoredProcResults>(...)
See Database.SqlQuery<T>(...)
I am a newbie in EF, i created a demo application in which i Assigned [StringLength] attribute to model.
[Required]
[StringLength(10)]
public string CustomerName { get; set; }
This worked fine with my EF-Code First approach.
But if i am removing this attribute, then the EF is throwing exception.
I want to know the association which EF created with these attributes
StringLength attribute can be applied to a string type property of a class. EF Code-First will set the size of a column as specified in StringLength attribute. Note that it can also be used with ASP.Net MVC as a validation attribute.
Source
When you don't specify a length, EF Code-First will generate a VARCHAR(MAX)column for your strings. Thats the missmatch you get when you first create the column with StringLength(10) and remove it afterwards.
I using vs2010 and the built-in EF designer against SQL server Compact 4.0 local database that in my project. ( design-first)
I tried to add (through the designer) to one of the entities a new property that doesn't exist in the DB (nor planed to) by: add-new scalar property.... , but when i was tring to validate it, i got an error:
property "x" is not map
my question:
can i add my own properties to the schema through the designer. and that properties won't be exist in the underline DB.(I thought i could)?
if I can, how?
You can add non db fields to your entity by creating a partial class of that entity with the required properties. These won't be used for the ORM.
public partial class MyEntity {
public string StringStatusCode { get;set;}
}
One of my entity classes would be possible to store in a sql server
database as a BIGINT. My question is: How do I get a Entity Framework
context to know how to store and retrieve instances of my entity class?
More detail. I'm using Noda Time, which can represent a (much) wider range of
dates than can SQL or .NET datetime (AND it's a dessert topping). My Entity Class, Happening, is a wrapper around NodaTime's
Instant class. I can set a Happening from a long, and get a long from
a happening with methods like .SetFromLong(long instant) and .ToLong().
Currently I have my model working, saving classes that contain
properties of the dot net DateTime type. If instead I want to use properties
of my custom type "Happening", how do I tell Entity Framework how to save those?
If I'm reading this article about Modeling and Mapping am I on the
right track or missing something simpler?
http://msdn.microsoft.com/en-us/library/bb896343.aspx
I'm using entity framework 4.
What i recommend doing is adding 2 properties on your entity a NodaTime and a long, and exclude your NodaTime property using [NotMapped] in your EF model, then in your getter/setter update the long.
ie
public class MyEntity{
public long TimeAsLong{get;set;}
[NotMapped]
public Happening {
get{
return new Happening().SetFromLong(TimeAsLong);
}
set {
TimeAsLong = value.ToLong();
}
}
}
The effect of this will be that the long is stored in the db but you can access it on the class via NodaTime