SQL injection
Using a SQL update statement like this one (spacing is optional):

UPDATE players
   SET name = 'Smith, Steve', score = 42, active = TRUE
   WHERE jerseyNum = 99
Non-parameterized SQL is the GoTo statement of database programming. Don't do it, and make sure your coworkers don't either.
open System.Data.SqlClient
 
[<EntryPoint>]
let main argv = 
    use tConn = new SqlConnection("ConnectionString")
 
    use tCommand = new SqlCommand()
    tCommand.Connection <- tConn
    tCommand.CommandText <- "UPDATE players SET name = @name, score = @score, active = @active WHERE jerseyNum = @jerseyNum"
 
    tCommand.Parameters.Add(SqlParameter("@name", System.Data.SqlDbType.VarChar).Value = box "Smith, Steve") |> ignore
    tCommand.Parameters.Add(SqlParameter("@score", System.Data.SqlDbType.Int).Value = box 42) |> ignore
    tCommand.Parameters.Add(SqlParameter("@active", System.Data.SqlDbType.Bit).Value = box true) |> ignore
    tCommand.Parameters.Add(SqlParameter("@jerseyNum", System.Data.SqlDbType.Int).Value = box 99) |> ignore
 
    tCommand.ExecuteNonQuery() |> ignore
    0