Programación de bases de datos con Visual Basic .NET

Listado 5.25

Uso de las clases UniqueConstraint y ForeignKeyConstraint.

Dim cn As SqlConnection

Dim cmd As SqlCommand

Dim miDataSet As DataSet

Dim sqldad As SqlDataAdapter

Dim intRegistros As Integer

Dim UC As UniqueConstraint

Dim FKC As ForeignKeyConstraint

Dim UCColumna As DataColumn

Dim FKCColumna1 As DataColumn

Dim FKCColumna2 As DataColumn

cn = New SqlConnection()

cn.ConnectionString = "data source=rhpc;initial catalog=pubs; " _

& "user id=sa;password="

cn.Open()

miDataSet = New DataSet()

cmd = New SqlCommand("SELECT * FROM publishers", cn)

sqldad = New SqlDataAdapter(cmd)

intRegistros = sqldad.Fill(miDataSet, "Publishers")

cmd = New SqlCommand("SELECT * FROM titles", cn)

sqldad = New SqlDataAdapter(cmd)

intRegistros = sqldad.Fill(miDataSet, "Titles")

UCColumna = miDataSet.Tables("Publishers").Columns("Pub_id")

UC = New UniqueConstraint(UCColumna)

miDataSet.Tables("Publishers").Constraints.Add(UC)

FKCColumna1 = miDataSet.Tables("Publishers").Columns("Pub_id")

FKCColumna2 = miDataSet.Tables("Titles").Columns("Pub_id")

FKC = New ForeignKeyConstraint(FKCColumna1, FKCColumna2)

miDataSet.Tables("Titles").Constraints.Add(FCK)