VB.Net/Database ADO.net/DataSet Update

Содержание

1 Modify Data table: add a row and update a cell
2 Set new cell value in DataSet
3 Update a row in DataSet update event
4 Use DataSet to query and update Row

Modify Data table: add a row and update a cell

Imports System
Imports System.Data
Imports System.Data.SqlClient

public class MainClass
   Shared Sub Main()
      Dim thisConnection As New SqlConnection("server=(local)\SQLEXPRESS;" & _
          "integrated security=sspi;database=MyDatabase")
      " Sql Query 
      Dim sql As String = "SELECT * FROM Employee"
      Try
         " Create Data Adapter
         Dim da As New SqlDataAdapter
         da.SelectCommand = New SqlCommand(sql, thisConnection)
         " Create and fill Dataset
         Dim ds As New DataSet
         da.Fill(ds, "Employee")
         " Get the Data Table
         Dim dt As DataTable = ds.Tables("Employee")
         " Display Rows Before Changed
         Console.WriteLine("Before altering the dataset")
         For Each row As DataRow In dt.Rows
            Console.WriteLine("{0} | {1} | {2}", _
               row("ID").ToString().PadRight(10), _
               row("FirstName").ToString().PadRight(10), _
               row("LastName"))
         Next
         " FirstName column should be nullable
         dt.Columns("FirstName").AllowDBNull = True
         " Modify city in first row
         dt.Rows(0)("FirstName") = "Birm"
         " Add A Row
         Dim newRow As DataRow = dt.NewRow()
         newRow("ID") = "99"
         newRow("FirstName") = "Ever"
         newRow("LastName") = "Dame"
         dt.Rows.Add(newRow)
         " Display Rows After Alteration
         Console.WriteLine("=========")
         Console.WriteLine("After altering the dataset")
         For Each row As DataRow In dt.Rows
            Console.WriteLine("{0} | {1} | {2}", _
               row("ID").ToString().PadRight(10), _
               row("FirstName").ToString().PadRight(10), _
               row("LastName"))
         Next
      Catch ex As SqlException
         " Display error
         Console.WriteLine("Error: " & ex.ToString())
      Finally
         " Close Connection
         thisConnection.Close()
         Console.WriteLine("Connection Closed")
      End Try
   End Sub
End Class

Set new cell value in DataSet

Imports System
Imports System.Collections
Imports System.Data
Imports System.IO
Imports System.Xml.Serialization
Imports System.Xml
Imports System.Windows.Forms
Imports System.Data.SqlClient
Imports System.Data.OleDb
Public Class MainClass
    Shared Sub Main()
        Dim form1 As Form = New Form1
        Application.Run(form1)
    End Sub
End Class




Public Class Form1
    Inherits System.Windows.Forms.Form
#Region " Windows Form Designer generated code "
    Public Sub New()
        MyBase.New()
        "This call is required by the Windows Form Designer.
        InitializeComponent()
        "Add any initialization after the InitializeComponent() call
    End Sub
    "Form overrides dispose to clean up the component list.
    Protected Overloads Overrides Sub Dispose(ByVal disposing As Boolean)
        If disposing Then
            If Not (components Is Nothing) Then
                components.Dispose()
            End If
        End If
        MyBase.Dispose(disposing)
    End Sub
    "Required by the Windows Form Designer
    Private components As System.ruponentModel.IContainer
    "NOTE: The following procedure is required by the Windows Form Designer
    "It can be modified using the Windows Form Designer.  
    "Do not modify it using the code editor.
    Friend WithEvents button1 As System.Windows.Forms.Button
    <System.Diagnostics.DebuggerStepThrough()> Private Sub InitializeComponent()
        Me.button1 = New System.Windows.Forms.Button()
        Me.SuspendLayout()
        "
        "button1
        "
        Me.button1.Font = New System.Drawing.Font("Microsoft Sans Serif", 9.75!, System.Drawing.FontStyle.Regular, System.Drawing.GraphicsUnit.Point, CType(0, Byte))
        Me.button1.Location = New System.Drawing.Point(10, 8)
        Me.button1.Name = "button1"
        Me.button1.Size = New System.Drawing.Size(240, 64)
        Me.button1.TabIndex = 1
        Me.button1.Text = "Update a record"
        "
        "Form1
        "
        Me.AutoScaleBaseSize = New System.Drawing.Size(5, 13)
        Me.ClientSize = New System.Drawing.Size(260, 81)
        Me.Controls.AddRange(New System.Windows.Forms.Control() {Me.button1})
        Me.FormBorderStyle = System.Windows.Forms.FormBorderStyle.FixedSingle
        Me.MaximizeBox = False
        Me.MinimizeBox = False
        Me.Name = "Form1"
        Me.Text = "Row Updating"
        Me.ResumeLayout(False)
    End Sub
#End Region
        Dim dbConn As New SqlConnection("Server=(local)\SQLEXPRESS;Initial Catalog=MyDatabase;Integrated Security=SSPI")
    Dim WithEvents da As New SqlDataAdapter("SELECT ID, FirstName, LastName FROM Employee", dbConn)
    Private Sub button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles button1.Click
        Dim cb As New SqlCommandBuilder(da)
        Dim ds As New DataSet("Employee")
        da.Fill(ds)
        ds.Tables(0).Rows(0)("ID") = "1"
        da.Update(ds.GetChanges())
    End Sub

    Private Sub da_RowUpdating(ByVal sender As Object, _
                               ByVal e As SqlRowUpdatingEventArgs) _
                               Handles da.RowUpdating
        " Only perform processing if this is an UPDATE statement
        If (e.StatementType = StatementType.Update) Then
            " Check that the original record is not changed
            Dim strSQL As String = "SELECT ID, FirstName, LastName " & _
                                   "FROM Employee WHERE "
            strSQL &= "ID="" & e.Row("ID", DataRowVersion.Original)
            strSQL &= "" AND "
            strSQL &= "FirstName="" & e.Row("FirstName", DataRowVersion.Original)
            strSQL &= "" AND "
            strSQL &= "LastName="" & e.Row("LastName", DataRowVersion.Original) & """
            " Open the connection
            dbConn.Open()
            " Create a command to retrieve the number of records affected
            Dim cmm As New SqlCommand(strSQL, dbConn)
            " If the number of records retrieved is zero, the record has changed
            If (cmm.ExecuteNonQuery() = 0) Then
                " Display the confirm message
                If (MessageBox.Show("The record you are attempting to modify has " & _
                                    "already changed by another user. Do you " & _
                                    "want to overwrite it?", "Update", _
                                    MessageBoxButtons.YesNo) = DialogResult.No) Then
                    " Skip the update for the current row
                    e.Status = UpdateStatus.SkipCurrentRow
                End If
            End If
            " Close the connection
            dbConn.Close()
        End If
    End Sub
End Class

Update a row in DataSet update event

Imports System
Imports System.Collections
Imports System.Data
Imports System.IO
Imports System.Xml.Serialization
Imports System.Xml
Imports System.Windows.Forms
Imports System.Data.SqlClient
Imports System.Data.OleDb
Public Class MainClass
    Shared Sub Main()
        Dim form1 As Form = New Form1
        Application.Run(form1)
    End Sub
End Class




Public Class Form1
    Inherits System.Windows.Forms.Form
#Region " Windows Form Designer generated code "
    Public Sub New()
        MyBase.New()
        "This call is required by the Windows Form Designer.
        InitializeComponent()
        "Add any initialization after the InitializeComponent() call
    End Sub
    "Form overrides dispose to clean up the component list.
    Protected Overloads Overrides Sub Dispose(ByVal disposing As Boolean)
        If disposing Then
            If Not (components Is Nothing) Then
                components.Dispose()
            End If
        End If
        MyBase.Dispose(disposing)
    End Sub
    "Required by the Windows Form Designer
    Private components As System.ruponentModel.IContainer
    "NOTE: The following procedure is required by the Windows Form Designer
    "It can be modified using the Windows Form Designer.  
    "Do not modify it using the code editor.
    Friend WithEvents button1 As System.Windows.Forms.Button
    <System.Diagnostics.DebuggerStepThrough()> Private Sub InitializeComponent()
        Me.button1 = New System.Windows.Forms.Button()
        Me.SuspendLayout()
        "
        "button1
        "
        Me.button1.Font = New System.Drawing.Font("Microsoft Sans Serif", 9.75!, System.Drawing.FontStyle.Regular, System.Drawing.GraphicsUnit.Point, CType(0, Byte))
        Me.button1.Location = New System.Drawing.Point(10, 8)
        Me.button1.Name = "button1"
        Me.button1.Size = New System.Drawing.Size(240, 64)
        Me.button1.TabIndex = 1
        Me.button1.Text = "Update a record"
        "
        "Form1
        "
        Me.AutoScaleBaseSize = New System.Drawing.Size(5, 13)
        Me.ClientSize = New System.Drawing.Size(260, 81)
        Me.Controls.AddRange(New System.Windows.Forms.Control() {Me.button1})
        Me.FormBorderStyle = System.Windows.Forms.FormBorderStyle.FixedSingle
        Me.MaximizeBox = False
        Me.MinimizeBox = False
        Me.Name = "Form1"
        Me.Text = "Row Updating"
        Me.ResumeLayout(False)
    End Sub
#End Region
        Dim dbConn As New SqlConnection("Server=(local)\SQLEXPRESS;Initial Catalog=MyDatabase;Integrated Security=SSPI")
    Dim WithEvents da As New SqlDataAdapter("SELECT ID, FirstName, LastName FROM Employee", dbConn)
    Private Sub button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles button1.Click
        Dim cb As New SqlCommandBuilder(da)
        Dim ds As New DataSet("Employee")
        da.Fill(ds)
        ds.Tables(0).Rows(0)("ID") = "1"
        da.Update(ds.GetChanges())
    End Sub

    Private Sub da_RowUpdating(ByVal sender As Object, _
                               ByVal e As SqlRowUpdatingEventArgs) _
                               Handles da.RowUpdating
        " Only perform processing if this is an UPDATE statement
        If (e.StatementType = StatementType.Update) Then
            " Check that the original record is not changed
            Dim strSQL As String = "SELECT ID, FirstName, LastName " & _
                                   "FROM Employee WHERE "
            strSQL &= "ID="" & e.Row("ID", DataRowVersion.Original)
            strSQL &= "" AND "
            strSQL &= "FirstName="" & e.Row("FirstName", DataRowVersion.Original)
            strSQL &= "" AND "
            strSQL &= "LastName="" & e.Row("LastName", DataRowVersion.Original) & """
            " Open the connection
            dbConn.Open()
            " Create a command to retrieve the number of records affected
            Dim cmm As New SqlCommand(strSQL, dbConn)
            " If the number of records retrieved is zero, the record has changed
            If (cmm.ExecuteNonQuery() = 0) Then
                " Display the confirm message
                If (MessageBox.Show("The record you are attempting to modify has " & _
                                    "already changed by another user. Do you " & _
                                    "want to overwrite it?", "Update", _
                                    MessageBoxButtons.YesNo) = DialogResult.No) Then
                    " Skip the update for the current row
                    e.Status = UpdateStatus.SkipCurrentRow
                End If
            End If
            " Close the connection
            dbConn.Close()
        End If
    End Sub
End Class

Use DataSet to query and update Row

Imports System
Imports System.Xml
Imports System.Xml.Schema
Imports System.IO
Imports System.Data.OleDb
Imports System.Data.rumon
Imports System.Data

Public Class MainClass
    
    Shared Sub Main()
        Dim dsUsers As New DataSet("Employee")
        Try
            " Define a connection object
            Dim dbConn As New OleDbConnection("Provider=Microsoft.Jet.OLEDB.4.0;Password=;User ID=Admin;Data Source=Employee.mdb")
            " Create a data adapter to retrieve records from db
            Dim daUsers As New OleDbDataAdapter("SELECT ID, FirstName, LastName FROM Employee", dbConn)
            " Define each column to map
            Dim dcmUserID As New DataColumnMapping("ID", "EmployeeID")
            Dim dcmFirstName As New DataColumnMapping("FirstName", "FirstName")
            Dim dcmLastName As New DataColumnMapping("LastName", "LastName")
            " Define the table containing the mapped columns
            Dim dtmUsers As New DataTableMapping("Table", "Employee")
            dtmUsers.ColumnMappings.Add(dcmUserID)
            dtmUsers.ColumnMappings.Add(dcmFirstName)
            dtmUsers.ColumnMappings.Add(dcmLastName)
            " Activate the mapping mechanism
            daUsers.TableMappings.Add(dtmUsers)
            " Fill the dataset
            daUsers.Fill(dsUsers)
            " Set the primary key in order to use the Find() method
            " below.
            Dim dcaKey() As DataColumn = {dsUsers.Tables(0).Columns("EmployeeID")}
            dsUsers.Tables(0).PrimaryKey = dcaKey
            " Declare a command builder to create SQL instructions
            " to create and update records.
            Dim cb = New OleDbCommandBuilder(daUsers)
            " Update an existing record in the DataSet
            Dim r As DataRow = dsUsers.Tables(0).Rows.Find(1)
            If Not r Is Nothing Then
                r("FirstName") = "Venus"
                r("LastName") = "Williams"
                " Update the record even in the database
                daUsers.Update(dsUsers.GetChanges())
                " Align in-memory data with the data source ones
                dsUsers.AcceptChanges()
                " Print successfully message
                Console.WriteLine("The record has been updated successfully.")
            Else
                Console.WriteLine("No record found...")
            End If
        Catch ex As Exception
            " Reject DataSet changes
            dsUsers.RejectChanges()
            " An error occurred. Show the error message
            Console.WriteLine(ex.Message)
        End Try 
    End Sub
End Class

<A href="http://www.vbex.ru/Code/VBDownload/Employee.zip">Employee.zip( 7 k)</a>

VB.Net/Database ADO.net/DataSet Update

Содержание

Modify Data table: add a row and update a cell

Set new cell value in DataSet

Update a row in DataSet update event

Use DataSet to query and update Row

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