I'm creating a template with two attributes that can not be repeated, a GUID and a string .
To make string ( not the primary key - primary key is GUID ) a unique field should I use HasIndex(x => x.Atributo).IsUnique(); ?
If not, what do you do?
Considering that you are using'Entity Framework 6 ', you would have two options.
"Fluent Api", which would be the example of your question. That is, yes you can and in my view should create a Unique Key , as in your example:
HasIndex(x=>x.Atributo).IsUnique()
The second form would be Data Annotation Atribute, it's an option but I do not like it because I work with "POCO" classes, and those attributes polouem the code. But it would look like this.
Imagining that your property is called X
[Index( "INDEX_x", IsUnique=true )]
public string x {get;set;}
Editing the answer to inform you that the solution also works for EF Core.