How to Manually Enter Keys into Entity Framework Tables?

Manually Specifying Primary Keys with Entity Framework

Entity Framework typically auto-generates primary keys, but situations may arise where you need to manually assign key values. This often leads to conflicts if auto-increment is enabled. Here's how to manage this:

To prevent Entity Framework from automatically generating primary keys, you can use either Fluent API or data annotations:

Method 1: Fluent API

This approach modifies the model builder:

<code class="language-csharp">modelBuilder.Entity<Event>().Property(e => e.EventID).HasDatabaseGeneratedOption(DatabaseGeneratedOption.None);</code>

If you encounter the error "Cannot insert explicit value for identity column in table 'Events' when IDENTITY_INSERT is set to OFF," you need to adjust the database settings:

1. Open SQL Server Management Studio (SSMS) and connect to your database.
2. Locate the 'Events' table.
3. Right-click the table, select "Properties," go to the "Options" tab.
4. In the "Identity Specification" section, set "Is Identity" to "No." Click "OK."

Method 2: Data Annotations

Alternatively, you can use attributes directly in your entity class:

<code class="language-csharp">[Key]
[DatabaseGenerated(DatabaseGeneratedOption.None)]
public int EventID { get; set; }</code>

Both methods achieve the same result: disabling auto-increment for the EventID column, allowing you to specify the key values directly when inserting data into your Events table. Remember to choose one method and apply it consistently. Using both simultaneously will likely cause conflicts.

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