Hexagonal Architecture. No ORM.

gistfile1.fs

module domain =
    type post = { id: Guid; title: string; content: string; author_id: Guid }
    type author = { id: Guid; name: string; }
    type crudAction = Create | Update | Delete
    type change = { action: crudAction; entity: obj; id: Guid } 
    
    let addPost (p:post) : seq<change> = 
        // do stuff
        seq { yield {action = Create; entity = box p; id = p.id} }
        
    let countWordsByAuthor postsByAuthor =
        Seq.map (fun p -> (p.content.Split [|' '|]).Length) postsByAuthor
            |> Seq.sum

module persistence =
    open domain
    let private saveChange c =
        match c with
            | { action = Create; entity = e; id = id } -> printfn "creatin' %A" e
            | { action = Update; entity = e; id = id } -> printfn "updatin' %A" e
            | { action = Delete; entity = e; id = id } -> printfn "deletin' %A" e
    
    let saveChanges cs = 
        Seq.iter saveChange cs
        
    let query view id : seq<post> = 
        let p = { 
                id= Guid.NewGuid(); 
                title = "F# syntax in 60 seconds";
                content = "Here is a very quick overview on how to read F# code for newcomers unfamiliar with the syntax.";
                author_id = Guid.NewGuid()
                }
        seq { yield p }
    
open domain
open persistence

let scott = { id = Guid.NewGuid(); name = "Scott Wlaschin" }
let whyUseF = { 
                id= Guid.NewGuid(); 
                title = "Why Use F#";
                content = "Because I like it";
                author_id = scott.id
              }
 
addPost whyUseF 
    |> saveChanges
    
// queries with logic like ...
query "PostsByAuthor" scott.id
    |> countWordsByAuthor 
    |> Console.WriteLine

As pointed out by Mr Harcourt, domain events cause problems in this model.