I'm learning EF Core and making ID on the below POCO Road's property rid
public class Road
{
public int rid { get; set; }
public string rname { get; set; }
public string zip { get; set; }
},
Currently my solution is two-step:
1: adding PK
2: using ValueGeneratedOnAdd() method
modelBuilder.Entity<Road>()
.HasKey(x => x.rid);
modelBuilder.Entity<Road>()
.Property(x =>x.rid)
.ValueGeneratedOnAdd();
I want a one-step solution, how to do it?
You can make an extension method:
public static class ModelBuilderExtensions
{
public static EntityTypeBuilder<T> HasKeyWithValueGeneratedOnAdd<T>(
this EntityTypeBuilder<T> b,
Expression<Func<T, object>> expression)
where T : class
{
b.HasKey(expression);
b.Property(expression).ValueGeneratedOnAdd();
return b;
}
}
Then use it as a one-liner:
modelBuilder.Entity<Road>().HasKeyWithValueGeneratedOnAdd(x => x.rid);
public class Road
{
[Key]
public int rid { get; set; }
public string rname { get; set; }
public string zip { get; set; }
},
Related
I'm trying to query on a LicenseId, which is unique and lives in a doubly nested object. I want to return the entire SoftwareOrderEntity object and filter out everything except the result with the matching Id. So far nothing I have tried works due to limitations with Cosmos...
Classes:
public class SoftwareOrderEntity : IUpdateAuditable, IInsertAuditable
{
public string? OrderId { get; set; }
public SoftwareOrderEntityExternalProperties? ExternalProperties { get; set; }
}
public class SoftwareOrderEntityExternalProperties
{
public List<ProductsOnOrder>? ProductsOnOrder { get; set; }
}
public class ProductsOnOrder
{
public string? ProductId { get; set; }
public List<ProductLicenseIds>? ProductLicenseIds { get; set; }
}
public class ProductLicenseIds
{
public string? LicenseId { get; set; }
public string? AssignedEntityId { get; set; }
}
I've tried many variations of LINQ, such as...
SoftwareOrders.Where(x => x.ExternalProperties.ProductsOnOrder.Where(y => y.ProductLicenseIds.Where(z => z.LicenseId.Contains(licenseId)).Count() > 0).Count() > 0);
And
var res = from c in domainContext.SoftwareOrders
from m in c.ExternalProperties.ProductsOnOrder
from x in m.ProductLicenseIds
where x.LicenseId == licenseId
select c;
EDIT: Any() is not supported by cosmos, which is part of the issue
I want to create a catalog products. There may be catalogs or products on each node.
I decided to use the composite design pattern.
I will download the node with the children using CTE. Unfortunately there was a problem, because EF Core doesn't add parentId in the CategoryProducts table.
Additionally the class (Category as my Composite) has its own CategoryDetails class, (Product as my Leaf) has its own ProductDetails class.
How do I configure EF Core to recursively get nodes from the tree?
Is CTE a good idea?
public enum CategoryProductType
{
Category,
Product
}
public abstract class CategoryProduct
{
public Guid Id { get; private set; }
public string Name { get; private set; }
public CategoryProductType Type { get; private set; }
protected CategoryProduct(Guid id, string name, CategoryProductType type)
{
Id = id;
Name = name;
Type = type;
}
}
public class Category : CategoryProduct
{
public string Code { get; private set; }
public CategoryDetails CategoryDetails { get; private set; }
private ICollection<CategoryProduct> _children { get; set; } = new Collection<CategoryProduct>();
public IEnumerable<CategoryProduct> Children => _children;
public Category(Guid id, string name, string code)
: base(id, name, CategoryProductType.Category)
{
Code = code;
}
}
public class CategoryDetails
{
public Guid CategoryId { get; private set; }
public Category Category { get; private set; }
public string Description { get; private set; }
private CategoryDetails() { }
public CategoryDetails(Category category, string description)
{
Category = category);
Description = description);
}
}
public class Product : CategoryProduct
{
public string Index { get; private set; }
public ProductDetails ProductDetails { get; private set; }
public Product(Guid id, string name, string index)
: base(id, name, CategoryProductType.Product)
{
SetIndex(index);
}
}
EF Core Setting:
Unfortunately I don't know anything about CTE Recursion.
However, this is an example on how I modeled a hierarchical structure (i.e. a tree) with EF Core, hopefully it can help you.
public class TreeNode
{
public int TreeNodeId { get; private set; }
public int? ParentTreeNodeId { get; set; }
public TreeNode ParentTreeNode { get; set; }
public List<TreeNode> ChildrenTreeNodes { get; set; }
}
protected override void OnModelCreating(ModelBuilder modelBuilder)
{
modelBuilder.Entity<TreeNode>(entity =>
{
entity.HasOne(n => n.ParentTreeNode)
.WithMany(n => n.ChildrenTreeNodes)
.HasForeignKey(n => n.ParentTreeNodeId);
});
}
This the table structure I have:
#region Tables
public class WorkoutProfile
{
public WorkoutProfile()
{
WorkoutExercises = new List<WorkoutExercise>();
}
[Key]
public int ProfileId { get; set; }
public string Name { get; set; }
public int Sets { get; set; }
public int RestAfterSetInSeconds { get; set; }
public virtual User User { get; set; }
public virtual ICollection<WorkoutExercise> WorkoutExercises { get; set; }
}
public class WorkoutExercise
{
[Key]
public int WorkoutId { get; set; }
public virtual Exercise Exercise { get; set; }
public int Order { get; set; }
public int WorkoutTimeInSeconds { get; set; }
public int RestAfterInSeconds { get; set; }
}
public class Exercise
{
[Key]
public long ExerciseId { get; set; }
public string Title { get; set; }
public string Visualisation { get; set; }
public bool IsDefault { get; set; } // Is exersice should be included when user first registers
}
public class User
{
[Key]
public long UserId { get; set; }
public string Email { get; set; }
public DateTime Registered { get; set; }
}
#endregion Tables
In the repository class I run the following linq query:
return context
.WorkoutProfiles.Include(w => w.WorkoutExercises)
.Where(q => q.User.UserId == userId && q.ProfileId == profileId)
.FirstOrDefault();
and I receive the good and old "Object reference not set to an instance of an object". When examining the result, see that Exercises property in WorkoutExercises is null.
This is how the database is created using code first approach:
So, the question is: why Exercises not included in WorkoutExercises object? Do I need to include it somehow? I am using .NET Core 2
The simple answer would be no lazy loading in EFCore. Not Released yet but if you want to dabble with alpha code, its in the repository. Based on your classes there are no collections for exercises in WorkoutExcercise.
Then you need to ThenInclude(w => w.Exercises) following your Include clause since EFCore doesn't do lazy loading.
I found a solution following this post
Altered my code as following:
var top = context
.Set<WorkoutProfile>()
.Where(q => q.ProfileId == profileId && q.User.UserId == userId)
.Include(q => q.WorkoutExercises)
.SingleOrDefault();
context
.Entry(top)
.Collection(e => e.WorkoutExercises)
.Query()
.OfType<WorkoutExercise>()
.Include(e => e.Exercise)
.Load();
And it worked
I have 2 entities:
public partial class GPSdevice
{
[System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Usage", "CA2214:DoNotCallOverridableMethodsInConstructors")]
public GPSdevice()
{
}
public int ID { get; set; }
public string UserName { get; set; }
[System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Usage", "CA2227:CollectionPropertiesShouldBeReadOnly")]
public virtual Truck Truck { get; set; }
}
public partial class Truck
{
[System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Usage", "CA2214:DoNotCallOverridableMethodsInConstructors")]
public Truck()
{
}
public int TruckID { get; set; }
public string TruckNo { get; set; }
public string Make { get; set; }
[ForeignKey("GPSdevice")]
public int? GPSdeviceID { get; set; }
public virtual GPSdevice GPSdevice { get; set; }
}
I want to create a relationship one-to-one-or-zero (each GPSdevice can be linked to any truck (but to one and only one) or not linked at all)
I write the following code:
modelBuilder.Entity<GPSdevice>()
.HasOptional(e => e.Truck)
.WithOptionalPrincipal()
.WillCascadeOnDelete(false);
but it creates the following migration:
public override void Up()
{
AddColumn("dbo.Truck", "GPSdevice_ID", c => c.Int());
CreateIndex("dbo.Truck", "GPSdeviceID");
CreateIndex("dbo.Truck", "GPSdevice_ID");
AddForeignKey("dbo.Truck", "GPSdeviceID", "dbo.GPSdevices", "ID");
AddForeignKey("dbo.Truck", "GPSdevice_ID", "dbo.GPSdevices", "ID");
}
why it creates one more field and how to use the current field GPSdeviceID instead?
ADDED:
If I remove
public int? GPSdeviceID { get; set; }
and add MapKey:
modelBuilder.Entity<GPSdevice>()
.HasOptional(e => e.Truck)
.WithOptionalPrincipal(e=>e.GPSdevice).Map(p=>p.MapKey("GPSdeviceID"))
.WillCascadeOnDelete(false);
in result I get the following migration code:
public override void Up()
{
CreateIndex("dbo.Truck", "GPSdeviceID");
AddForeignKey("dbo.Truck", "GPSdeviceID", "dbo.GPSdevices", "ID");
}
then I get the following error:
There are no primary or candidate keys in the referenced table
'dbo.GPSdevices' that match the referencing column list in the foreign
key 'FK_dbo.Truck_dbo.GPSdevices_GPSdeviceID'. Could not create
constraint or index. See previous errors.
Use this :
public partial class GPSdevice
{
public GPSdevice()
{
}
public int ID { get; set; }
public string UserName { get; set; }
public virtual Truck Truck { get; set; }
}
public partial class Truck
{
public Truck()
{
}
public int TruckID { get; set; }
public string TruckNo { get; set; }
public string Make { get; set; }
public virtual GPSdevice GPSdevice { get; set; }
}
modelBuilder.Entity<GPSdevice>()
.HasOptional(o => o.Truck)
.WithRequired(ad => ad.GPSdevice);
modelBuilder.Entity<Truck>()
.HasKey(e => e.TruckID);
I am relatively new to the Code First approach to Entity Framework. I have used the Database First approach for a while now, but the Code First seems to be a better fit for the application I am currently developing. I am working with an existing MS SQL database, and I am not allowed to make any changes whatsoever to the database. The reason why I am using Code First is because the Fluent API allows me to dynamically assign a table name to a class.
That said, I have a predicament where I need to assign a relationship between 2 tables. One table, ArCodes, has a composite key made up of the CodeType and the Code (both are strings). The CodeType column determins the type of code and the Code column is the identifier unique to the code type.
public class ArCode {
[Column("cod_typ", Order = 0), Key]
public string CodeType { get; set; }
[Column("ar_cod", Order = 1), Key]
public string Code { get; set; }
[Column("desc")]
public string Description { get; set; }
}
The other table, Invoices, needs to have a relationship to the ArCodes table for both a "ship via" code and a "terms" code.
public class Invoice {
[Column("pi_hist_hdr_invc_no"), Key]
public int InvoiceNumber { get; set; }
[Column("shp_via_cod")]
public string ShipViaCode { get; set; }
public ArCode ShipVia { get; set; }
[Column("terms_cod")]
public string TermsCode { get; set; }
public ArCode Terms { get; set; }
}
I would like to setup the relationship for both the "ShipVia" property and the "Terms" property. However, I am not sure how to do so in regards to the CodeType portion of the composite key. For "ship via" codes the Code Type should be "S", and code "terms" codes, the code type should be "T".
I have tried the following in by DB Context, but it did not work:
protected override void OnModelCreating(DbModelBuilder modelBuilder) {
// setup the table names
modelBuilder.Entity<ArCode>().ToTable("ARCODS" + CompanyCode);
modelBuilder.Entity<Invoice>().ToTable("IHSHDR" + CompanyCode);
//
// setup the relationships
//
// 1 Invoice <--> 0-1 Ship Via AR Codes
modelBuilder.Entity<Invoice>()
.HasOptional(invoice => invoice.ShipVia)
.WithMany()
.HasForeignKey(invoice => new { TheType = "S", invoice.ShipViaCode })
;
base.OnModelCreating(modelBuilder);
}
Any help would be appreciated.
Update #1
Ok, I reduced my code to its simplest form, and I followed the solution as provided by #GertArnold.
public abstract class ArCode {
[Column("cod_typ")]
public string CodeType { get; set; }
[Column("ar_cod")]
public string Code { get; set; }
[Column("terms_desc")]
public string TermsDescription { get; set; }
[Column("terms_typ")]
public string TermsType { get; set; }
[Column("shp_via_desc")]
public string ShipViaDescription { get; set; }
[Column("tax_desc")]
public string TaxDescription { get; set; }
}
public class TermsCode : ArCode { }
public class ShipViaCode : ArCode { }
public class Invoice {
[Column("pi_hist_hdr_invc_no"), Key]
public int InvoiceNumber { get; set; }
[Column("hdr_invc_dat")]
public DateTime InvoiceDate { get; set; }
[Column("shp_via_cod")]
public string ShipViaCode { get; set; }
public ShipViaCode ShipVia { get; set; }
[Column("terms_cod")]
public string TermsCode { get; set; }
public TermsCode Terms { get; set; }
public Invoice() {
}
}
public class PbsContext : DbContext {
public DbSet<Invoice> Invoices { get; set; }
protected override void OnModelCreating(DbModelBuilder modelBuilder) {
modelBuilder.Entity<Invoice>().ToTable("IHSHDR");
modelBuilder.Entity<ArCode>().HasKey(r => r.Code).ToTable("ARCODS");
modelBuilder.Entity<TermsCode>().Map(m => m.Requires("CodeType")
.HasValue("T").HasColumnType("varchar").HasMaxLength(1).IsRequired())
.ToTable("ARCODS");
modelBuilder.Entity<ShipViaCode>().Map(m => m.Requires("CodeType")
.HasValue("S").HasColumnType("varchar").HasMaxLength(1).IsRequired())
.ToTable("ARCODS");
base.OnModelCreating(modelBuilder);
}
public PbsContext()
: base("name=PbsDatabase") {
}
}
However, the following code returns an error:
PbsContext context = new PbsContext();
var invoice = context.Invoices.OrderByDescending(r => r.InvoiceDate).FirstOrDefault();
error 3032: Problem in mapping fragments starting at line 28:Condition member 'ArCode.cod_typ' with a condition other than 'IsNull=False' is mapped. Either remove the condition on ArCode.cod_typ or remove it from the mapping.
If I remove the "CodeType" column from the ArCode class and change all "CodeType" references to the database column name of "cod_typ" within the OnModelCreating event, then the statement above executes without error. However, invoice.ShipVia and invoice.Terms will both be null event though there is a matching record in the database.
Update #2
public abstract class ArCode {
[Column("ar_cod")]
public string Code { get; set; }
[Column("terms_desc")]
public string TermsDescription { get; set; }
[Column("terms_typ")]
public string TermsType { get; set; }
[Column("shp_via_desc")]
public string ShipViaDescription { get; set; }
[Column("tax_desc")]
public string TaxDescription { get; set; }
}
public class TermsCode : ArCode { }
public class ShipViaCode : ArCode { }
public class Invoice {
[Column("pi_hist_hdr_invc_no"), Key]
public int InvoiceNumber { get; set; }
[Column("hdr_invc_dat")]
public DateTime InvoiceDate { get; set; }
[Column("shp_via_cod")]
public ShipViaCode ShipVia { get; set; }
[Column("terms_cod")]
public TermsCode Terms { get; set; }
public Invoice() {
}
}
public class PbsContext : DbContext {
public DbSet<Invoice> Invoices { get; set; }
protected override void OnModelCreating(DbModelBuilder modelBuilder) {
modelBuilder.Entity<Invoice>().ToTable("IHSHDR");
modelBuilder.Entity<ArCode>().HasKey(r => r.Code).ToTable("ARCODS");
modelBuilder.Entity<TermsCode>().Map(m => m.Requires("CodeType")
.HasValue("T").HasColumnType("varchar").HasMaxLength(1).IsRequired())
.ToTable("ARCODS");
modelBuilder.Entity<ShipViaCode>().Map(m => m.Requires("CodeType")
.HasValue("S").HasColumnType("varchar").HasMaxLength(1).IsRequired())
.ToTable("ARCODS");
base.OnModelCreating(modelBuilder);
}
public PbsContext()
: base("name=PbsDatabase") {
}
}
Now, the following code returns an error:
PbsContext context = new PbsContext();
var invoice = context.Invoices.OrderByDescending(r => r.InvoiceDate).FirstOrDefault();
EntityCommandExecutionException - Invalid column name 'ShipVia_Code'. Invalid column name 'Terms_Code'.
What you want is impossible for EF. ArCode has a composite key, so any association to it will have to use two Properties. That means that in Invoice you'd need four properties (two pairs) to refer to the two ArCode objects. But two of these properties (those for CodeType) are not backed up by columns in the database, so EF can not map them.
But... there is a way that may help you out. You could create two derived classes from ArCode and let Invoice refer to those by single-property associations. But then you have to divert from the model as such and fool EF a bit by defining a single key:
public abstract class ArCode { ... } // abstract!
public class TermsCode : ArCode { }
public class ShipViaCode : ArCode { }
protected override void OnModelCreating(DbModelBuilder modelBuilder)
{
modelBuilder.Entity<Invoice>().ToTable("IHSHDR");
modelBuilder.Entity<Invoice>().HasOptional(i => i.Terms).WithOptionalDependent().Map(m => m.MapKey("terms_cod"));
modelBuilder.Entity<Invoice>().HasOptional(i => i.ShipVia).WithOptionalDependent().Map(m => m.MapKey("shp_via_cod"));
modelBuilder.Entity<ArCode>().HasKey(a => a.Code).ToTable("ARCODS");
modelBuilder.Entity<TermsCode>().Map(m => m.Requires("CodeType")
.HasValue("T").HasColumnType("varchar").HasMaxLength(1).IsRequired())
.ToTable("ARCODS");
modelBuilder.Entity<ShipViaCode>().Map(m => m.Requires("CodeType")
.HasValue("S").HasColumnType("varchar").HasMaxLength(1).IsRequired())
.ToTable("ARCODS");
base.OnModelCreating(modelBuilder);
}
public class Invoice
{
[Column("pi_hist_hdr_invc_no"), Key]
public int InvoiceNumber { get; set; }
public ShipViaCode ShipVia { get; set; }
public TermsCode Terms { get; set; }
}
This may work for you if you don't have to insert ARCODS records through EF. It won't allow you to insert records with identical Codes, although the database would allow it. But I expect the content of ARCODS to be pretty stable and maybe it is enough to fill it with a script.