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VisualizaçõesCode-first migration: How to set default value for new property?
I am using EF6 for storing instances of the report class in my database. The database already contains data. Say I wanted to add a property to report,
public class report {
// ... some previous properties
// ... new property:
public string newProperty{ get; set; }
}
Now if I go to the package-manager console and execute
add-migration Report-added-newProperty
update-database
I will get a file in the '/Migrations' folder adding a newProperty column to the table. This works fine. However, on the older entries in the database, the value for the newProperty is now an empty string. But I want it to be, e.g., "old".
So my question is: How do I set default values for new properties (of any type) in the migration script (or elsewhere)?
3 Respostas
Responde à pergunta0
If you see the generated migration code you will see AddColumn
AddColumn("dbo.report", "newProperty", c => c.String(nullable: false));
You can add defaultValue
AddColumn("dbo.report", "newProperty",
c => c.String(nullable: false, defaultValue: "old"));
Or add defaultValueSql
AddColumn("dbo.report", "newProperty",
c => c.String(nullable: false, defaultValueSql: "GETDATE()"));
0
Hope it helps someone. Putting everything together from previous answers (example using a boolean property):
1) Add a new property to the entity.
/// <summary>
/// Determines if user is enabled or not. Default value is true
/// </summary>
public bool IsEnabled { get; set; }
2) Run the command below to add the new change in the migrations.
add-migration addIsEnabledColumn
3) A migration file is created from the command above, open that file.
4) Set the default value.
public override void Up()
{
AddColumn(
"dbo.AspNetUsers",
"IsEnabled",
c => c.Boolean(
nullable: false,
defaultValue: true
)
);
}
0
You have to change the line in your migration script which adds the the property/column like this:
AddColumn("dbo.reports", "newProperty", c => c.String(nullable: false, defaultValue: "test"));