Develop an interface for interacting with a database

Develop NetLogics that: insert values into the database, query the database, and display the query results.

Figure 1. Application example




Tip: You can download a sample project from: InteractWithDatabase.zip

Prerequisites

Create a project.

To develop the project
  1. Create the application interface.
  2. Create a database.
  3. Develop a NetLogic for inserting random values.
  4. Develop a NetLogic for displaying a query result.
  5. Save the project.

  • Select Run to run the project using the client emulator to test your project. To run the project on a remote client, see Add a client device.

  • Expand the project by adding more interface elements and Insert, Update, Delete, and Select methods. 
        [ExportMethod]
    public void Insert(int value) {
        var values = new object[1,2];
        values[0,0] = DateTime.Now;
        values[0,1] = value;
        myTable.Insert(dbColumns, values);
        Log.Info("Insert","Inserted value: " + value.ToString());
    }

    [ExportMethod]
    public void Update(int value, DateTime timestamp) {
        Object[,] ResultSet;
        String[] Header;
        myStore.Query("UPDATE Demo SET Value = " + value + " WHERE Timestamp = \"" + timestamp.ToString("o", CultureInfo.InvariantCulture) + "\"" , out Header, out ResultSet);
        Log.Info("Update", "Updated last record");
    }

    [ExportMethod]
    public void Delete(int value) {
        Object[,] ResultSet;
        String[] Header;
        myStore.Query("DELETE FROM Demo WHERE Value<=65535 ORDER BY Timestamp DESC LIMIT 1", out Header, out ResultSet);
        Log.Info("Delete", "Deleted last record");
    }

    [ExportMethod]
    public void Select(out int value) {
        Object[,] ResultSet;
        String[] Header;
        myStore.Query("SELECT * FROM Demo ORDER BY Timestamp DESC LIMIT 1", out Header, out ResultSet);
        value = Convert.ToInt32(ResultSet[0,1]);
    }
    You can download a sample project from: InteractWithDatabaseExpanded.zip