open Fumble

// get the connection from the environment
let connectionString() = Env.getVar "app_db"

type User = { Id: int; Username: string }

let getUsers() : Result<User list, exn> =
    connectionString()
    |> Sql.connect
    |> Sql.query "SELECT * FROM dbo.[Users]"
    |> Sql.execute (fun read ->
        {
            Id = read.int "user_id"
            Username = read.string "username"
        })

open Fumble

// get the connection from the environment
let connectionString() = Env.getVar "app_db"

type User = { Id: int; Username: string; LastModified : Option<DateTime> }

let getUsers() : Result<User list, exn> =
    connectionString()
    |> Sql.connect
    |> Sql.query "SELECT * FROM dbo.[users]"
    |> Sql.execute(fun read ->
        {
            Id = read.int "user_id"
            Username = read.string "username"
            // Notice here using `orNone` reader variants
            LastModified = read.dateTimeOrNone "last_modified"
        })

open Fumble

// get the connection from the environment
let connectionString() = Env.getVar "app_db"

type User = { Id: int; Username: string; Biography : string }

let getUsers() : Result<User list, exn> =
    connectionString()
    |> Sql.connect
    |> Sql.query "select * from dbo.[users]"
    |> Sql.execute (fun read ->
        {
            Id = read.int "user_id";
            Username = read.string "username"
            Biography = defaultArg (read.stringOrNone "bio") ""
        })

open Fumble

// get the connection from the environment
let connectionString() = Env.getVar "app_db"

// get product names by category
let productsByCategory (category: string) : Result<string list, exn> =
    connectionString()
    |> Sql.connect
    |> Sql.query "SELECT name FROM dbo.[Products] where category = @category"
    |> Sql.parameters [ "@category", Sql.string category ]
    |> Sql.execute (fun read -> read.string "name")

open Fumble

// get the connection from the environment
let connectionString() = Env.getVar "app_db"

// check whether a user exists or not
let userExists (username: string) : Async<Result<bool, exn>> =
    async {
        return!
            connectionString()
            |> Sql.connect
            |> Sql.storedProcedure "user_exists"
            |> Sql.parameters [ "@username", Sql.string username ]
            |> Sql.execute (fun read -> read.bool 0)
            |> function
                | Ok [ result ] -> Ok result
                | Error error -> Error error
                | unexpected -> failwithf "Expected result %A"  unexpected
    }

open Fumble
open System.Data

// get the connection from the environment
let connectionString() = Env.getVar "app_db"

let executeMyStoredProcedure () : Async<int> =
    // create a table-valued parameter
    let customSqlTypeName = "MyCustomSqlTypeName"
    let dataTable = new DataTable()
    dataTable.Columns.Add "FirstName" |> ignore
    dataTable.Columns.Add "LastName"  |> ignore
    // add rows to the table parameter
    dataTable.Rows.Add("John", "Doe") |> ignore
    dataTable.Rows.Add("Jane", "Doe") |> ignore
    dataTable.Rows.Add("Fred", "Doe") |> ignore

    connectionString()
    |> Sql.connect
    |> Sql.storedProcedure "my_stored_proc"
    |> Sql.parameters
        [ "@foo", Sql.int 1
          "@people", Sql.table (customSqlTypeName, dataTable) ]
    |> Sql.executeNonQueryAsync