I am learning LINQ with F# 3.0. I want to know how to re-write my old code to use new LINQ features in F# 3.0 For example, I have created a simple data table in SQL Server 2008 R2, the database name is myDatabase.
-- Create the Table1 table.
CREATE TABLE [dbo].[Table1] (
[Id] INT NOT NULL,
[TestData1] INT NOT NULL,
[TestData2] FLOAT (53) NOT NULL,
[Name] NTEXT NOT NULL,
PRIMARY KEY CLUSTERED ([Id] ASC)
);
For F# 2.0, I can use Dataset to add new rows, like this:
#light
open System
open System.Collections.Generic
open System.Data
open System.Data.SqlClient
let sqlConn = "server=(local); Integrated Security=True; Database=MyDatabase"
let connDB = new SqlConnection(sqlConn)
let sql = "SELECT * FROM Table1"
let da = new SqlDataAdapter(sql, connDB)
let ds = new DataSet()
da.Fill(ds) |> ignore
let commandBuilder: SqlCommandBuilder = new SqlCommandBuilder(da)
for i = 0 to 1 do
let newDR: DataRow = ds.Tables.Item(0).NewRow()
newDR.Item(0) <- (i + 1)
newDR.Item(1) <- (i * 10)
newDR.Item(2) <- ( decimal i ) * 5.0M
newDR.Item(3) <- "Testing" + (i + 1).ToString()
ds.Tables.Item(0).Rows.Add(newDR)
da.Update(ds) |> ignore
Now with F# 3.0, how I can re-write the add new rows code better? I think I can wrtie some code like:
#light
open System
open System.Data.Linq
open Microsoft.FSharp.Data.TypeProviders
open Microsoft.FSharp.Linq
[<Generate>]
type dbSchema = SqlDataConnection<"Data Source=.;Initial Catalog=MyDatabase;Integrated Security=True">
let db = dbSchema.GetDataContext()
try
db.DataContext.ExecuteCommand("INSERT INTO Table1 (Id, TestData1, TestData2, Name) VALUES (1, 10, 0.0, 'Testing1')") |> ignore
with
| exn -> printfn "Exception:\n%s" exn.Message
try
db.DataContext.ExecuteCommand("INSERT INTO Table1 (Id, TestData1, TestData2, Name) VALUES (2, 20, 5.0, 'Testing2')") |> ignore
with
| exn -> printfn "Exception:\n%s" exn.Message
But I don't think the new way is better, in fact, I think it is even worse. In F# 2.0, I can use code to generate the values for data table, but if I have to write the static SQL statement, like "INSERT INTO Table1 VALUES(" with prefined values, then I think I would prefer to insert data records by hand from SQL Server Management Studio, as I can see the results immediately. Anyone has a better idea on this? Thanks, John