Databases
StackOverflow2013
Postsdbo
PO
 

Note that there are some explanatory texts on larger screens.

plurals
  1. PO
    primarykey
    data
    text
    <p>The below creates a single table but allows for a reference/navigation property to a field you may not always wish to load (in this case, a byte array called <code>Data</code>). This is known as table splitting.</p> <p>Key notes are to have both entities map to the same table (duh) using <code>TableAnnotion</code> and share the same primary key, which is used as the foreign key for the nav properties to one another.</p> <pre><code> [Table("Document")] public class Document { [Key] [ForeignKey("Data")] [DatabaseGenerated(DatabaseGeneratedOption.Identity)] public int DocumentId { get; set; } public string FileName { get; set; } public DateTime Created { get; set; } public virtual DocumentData Data { get; set; } } [Table("Document")] public class DocumentData { [Key] [ForeignKey("Document")] public int DocumentId { get; set; } public byte[] Data { get; set; } public virtual Document Document { get; set; } } public class DocEntities : DbContext { public DocEntities() : base("name=TestEntitiesCodeFirst") { } public DbSet&lt;Document&gt; Documents { get; set; } } static void Main(string[] args) { using (var db = new InheritTest.DocEntities()) { var doc = new Document() { Created = DateTime.Now, FileName = "Abc.txt", Data = new DocumentData() { Data = new byte[] { 0x50, 0x51, 0x52, 0x53 } } }; db.Documents.Add(doc); db.SaveChanges(); } using (var db = new InheritTest.DocEntities()) { db.Configuration.LazyLoadingEnabled = false; var doc = db.Documents.First(); if (doc.Data == null) { Console.WriteLine("doc.Data is null"); } db.Entry(doc).Reference(p =&gt; p.Data).Load(); if (doc.Data != null) { Console.WriteLine("doc.Data is not null"); Console.WriteLine(doc.Data.Data.Length); } } var input = Console.ReadLine(); } </code></pre> <p>Resulting table:</p> <pre><code>CREATE TABLE [dbo].[Document]( [DocumentId] [int] IDENTITY(1,1) NOT NULL, [FileName] [nvarchar](max) NULL, [Created] [datetime] NOT NULL, [Data] [varbinary](max) NULL, CONSTRAINT [PK_dbo.Document] PRIMARY KEY CLUSTERED ( [DocumentId] ASC )WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY] ) ON [PRIMARY] TEXTIMAGE_ON [PRIMARY] </code></pre>
    singulars
    1. This table or related slice is empty.
    1. POHow do omit a column(s) from the results of a LINQ query using Entity Framework 5
      singulars
      1. PTQuestion
    1. PTAnswer
    1. USMoho
    1. USMoho
    plurals
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. POHow do omit a column(s) from the results of a LINQ query using Entity Framework 5
      singulars
      1. PTQuestion
    1. This table or related slice is empty.
    1. VO
      singulars
      1. PO
      1. This table or related slice is empty.
      1. VTUpMod
    2. VO
      singulars
      1. PO
      1. This table or related slice is empty.
      1. VTAcceptedByOriginator
    3. VO
      singulars
      1. PO
      1. This table or related slice is empty.
      1. VTUpMod
    1. COThank you for the detail. I think that this approach is preferable to actually splitting the tables and having to mess around with managing more relationships.
      singulars
      1. PO
      1. USGary O. Stenstrom
 

Querying!

 
Guidance
A row detail

Detail views are divided into sections. All the information in the data section comes from columns in the selected row. The other sections display data from other, related rows.

Related data can be related in a to-one or a to-many fashion. Captions of data related in a to-many fashion link to a list view showing a filtered view of the table.

Try moving around until you find a non-empty to-many entry and click on the label to get to one. You can move back to the root by clicking on the database name in the header.

SQuiL has stopped working due to an internal error.

If you are curious you may find further information in the browser console, which is accessible through the devtools (F12).

Reload