Dataset Multi Tabella

Imports System.Data.SqlClient

Public Class Form1


Private Sub Form1_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
Dim Dbconn As New SqlConnection("Server=(Local); databaspubs; integrated security= true")

' dataset

Dim Ds As New DataSet("AutorsAndTitles")

' creazione del data adapter per gli autori

Dim DaAutors As New SqlDataAdapter("Select Au_id, Au_fname, au_Lname from authors", Dbconn)
DaAutors.Fill(Ds, "Author")

' creazione del data adapter per i titoli-Autori

Dim DaTitleAutors As New SqlDataAdapter("Select Au_id, Title_id from Titleauthors", Dbconn)
DaTitleAutors.Fill(Ds, "TitleAuthor")

' creazione del data adapter per i titoli

Dim DaTitle As New SqlDataAdapter("Select Title_id, Title from Titles", Dbconn)
DaTitle.Fill(Ds, "Titles")

' definizione della chiave primaria

Ds.Tables("Titles").Columns("Titles_id").Unique = True
Ds.Tables("Titles").Columns("Titles_id").AllowDBNull = False
Ds.Tables("Titles").PrimaryKey = New DataColumn() {Ds.Tables("titles").Columns("Title_Id")}

' definizione della chiave primaria

Ds.Tables("Author").Columns("Au_id").Unique = True
Ds.Tables("Author").Columns("Au_id").AllowDBNull = False
Ds.Tables("Author").PrimaryKey = New DataColumn() {Ds.Tables("Author").Columns("Au_id")}

' definizione della chiave primaria

Ds.Tables("TitleAuthor").PrimaryKey = New DataColumn() {Ds.Tables("TitleAuthor").Columns("Au_id"), _
Ds.Tables("TitleAuthor").Columns("Title_Id")}

' definizione costraints (primary-foreign key relationships

Dim Fk1 As New ForeignKeyConstraint("AutorsTiTleAutori", _
Ds.Tables("Author").Columns("Au_Id"), _
Ds.Tables("TitleAuthor").Columns("Au_Id"))
Ds.Tables("TitleAuthor").Constraints.Add(Fk1)

' definizione costraints (primary-foreign key relationships

Dim Fk2 As New ForeignKeyConstraint("TitlesTitleAutori", _
Ds.Tables("Titles").Columns("title_Id"), _
Ds.Tables("TitleAuthor").Columns("title_Id"))
Ds.Tables("TitleAuthor").Constraints.Add(Fk2)





End Sub