Skip index and FK creation using fluent API builder

[amyboose]

What problem are you trying to solve?

I want to suggest one additional option to conditionally remove index creation.
There is a solution to conditionally remove indexes using convention.

But it is better to understand when model building and index creation located in one single place. For example, I configure model using IEntityTypeConfigaration and this is the only one place where every model is configured.

Describe the solution you'd like

It can looks like this:

// first option
builder
    .HasOne(x => x.Product)
    .WithMany()
    .HasNoIndex();

// second option
builder
    .HasNoIndex(x => new { x.UserId, x.ProductId });

Also there is an extension for Postgresql "TimescalDb" and sometimes it doesn't allow to create foreign keys for time-series tables.
It can be useful to have API to skip creation foreign keys.

It can looks like this:

builder
    .HasOne(x => x.Product)
    .WithMany()
    .HasForeignKey(x => x.ProductId, createInDatabase: false);

[roji]

Not creating foreign keys in the database is tracked by #15854, you can follow that to be informed of progress.

Regarding not creating indexes... If you'd like to systematically stop creating indexes for foreign keys, that's something that generally belongs in a convention (like the one you linked to) - you should not be manually doing this for every index manually.

Otherwise, if you're really looking to selectively remove a specific index that's been configured by convention, @AndriySvyryd probably has the right answer (the metadata APIs can be used to manipulate indexes directly, but foreign key indexes are added only later...).