F# Connect to Online MySQL DB execute query - mysql

Question

I am making a F# project and need to do some database queries to an online mysql db. Can anyone please help me. I need something like this
\\ Connect to DB
let servername = "localhost"
let username = "username"
let password = "password"
\\ Code that connects to db
\\ Print error message if can connect
\\ Query
let query = "SELECT * FROM table ..."
\\ Code that executes query
\\ Error Message if query not executed

Answer 1

You should install the .NET driver for MySQL. Then install the SQLprovider. There are samples for MySQL in the docs. You would connect to the db and query it like this:
type sql = SqlDataProvider<
dbVendor,
connString,
ResolutionPath = resPath,
IndividualsAmount = indivAmount,
UseOptionTypes = useOptTypes,
Owner = "HR"
>
let ctx = sql.GetDataContext()
let employees =
ctx.Hr.Employees
|> Seq.map (fun e -> e.ColumnValues |> Seq.toList)
|> Seq.toList
connstring will be something like this:
[<Literal>]
let connString = "Server=localhost;Database=HR;User=root;Password=password"
You should also read https://msdn.microsoft.com/visualfsharpdocs/conceptual/walkthrough-accessing-a-sql-database-by-using-type-providers-%5bfsharp%5d

Answer 2

I would also say SQLProvider is the way to go as then you have a validation of your logics against your database and you notice if your database changes.
But you can connect manually if you want to:
// Reference Nuget package MySql.Data
//#r #"./../packages/MySql.Data/lib/net40/MySql.Data.dll"
open System
open MySql.Data.MySqlClient
let cstr = "server = localhost; database = myDatabase; uid = username;pwd = password"
let ExecuteSqlAsync (query : string) parameters =
use rawSqlConnection = new MySqlConnection(cstr)
async {
do! rawSqlConnection.OpenAsync() |> Async.AwaitIAsyncResult |> Async.Ignore
use command = new MySqlCommand(query, rawSqlConnection)
parameters |> List.iter(fun (par:string*string) -> command.Parameters.AddWithValue(par) |> ignore)
let! affectedRows = command.ExecuteNonQueryAsync() |> Async.AwaitTask
match affectedRows with
| 0 -> "ExecuteSql 0 rows affected: " + query |> Console.WriteLine
()
| x -> ()
}
let ExecuteSql (query : string) parameters =
use rawSqlConnection = new MySqlConnection(cstr)
rawSqlConnection.Open()
use command = new MySqlCommand(query, rawSqlConnection)
parameters |> List.iter(fun (par:string*string) -> command.Parameters.AddWithValue(par) |> ignore)
let affectedRows = command.ExecuteNonQuery()
match affectedRows with
| 0 -> "ExecuteSql 0 rows affected: " + query |> Console.WriteLine
()
| x -> ()