VB.Net by API/System.Data/DataTableMapping — различия между версиями
Admin (обсуждение | вклад) м (1 версия) |
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Текущая версия на 12:49, 26 мая 2010
DataTableMapping.ColumnMappings.Add
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("Users")
Try
Dim dbConn As New OleDbConnection("Provider=Microsoft.Jet.OLEDB.4.0;Password=;User ID=Admin;Data Source=Employee.mdb")
Dim daUsers As New OleDbDataAdapter("SELECT ID, FirstName, LastName FROM Employee", dbConn)
Dim dcmUserID As New DataColumnMapping("ID", "EmployeeID")
Dim dcmFirstName As New DataColumnMapping("FirstName", "FirstName")
Dim dcmLastName As New DataColumnMapping("LastName", "LastName")
Dim dtmUsers As New DataTableMapping("Table", "Employee")
dtmUsers.ColumnMappings.Add(dcmUserID)
dtmUsers.ColumnMappings.Add(dcmFirstName)
dtmUsers.ColumnMappings.Add(dcmLastName)
daUsers.TableMappings.Add(dtmUsers)
daUsers.Fill(dsUsers)
Dim cb As New OleDbCommandBuilder(daUsers)
Dim r As DataRow = dsUsers.Tables(0).NewRow()
r("FirstName") = "Eddie"
r("LastName") = "Robinson"
dsUsers.Tables(0).Rows.Add(r)
daUsers.Update(dsUsers.GetChanges())
dsUsers.AcceptChanges()
Catch ex As Exception
dsUsers.RejectChanges()
Console.WriteLine(ex.Message)
End Try
End Sub
End Class
New DataTableMapping
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 DoDataMappings(ByVal da As OleDbDataAdapter)
Try
" Define an array of column to map
Dim dcmMappedColumns() As DataColumnMapping = { _
New DataColumnMapping("ID", "EmployeeID"), _
New DataColumnMapping("FirstName", "FirstName"), _
New DataColumnMapping("LastName", "LastName")}
" Define the table containing the mapped columns
Dim dtmUsers As New DataTableMapping("Table", "Employee", _
dcmMappedColumns)
" Activate the mapping mechanism
da.TableMappings.Add(dtmUsers)
Catch ex As Exception
" An error occurred. Show the error message
Console.WriteLine(ex.Message)
End Try
End Sub
Shared Sub Main()
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)
Dim dsUsers As New DataSet("Employee")
DoDataMappings(daUsers)
" Fill the dataset
daUsers.Fill(dsUsers)
" Go through the records and print them using the mapped names
Dim r As DataRow
For Each r In dsUsers.Tables("Employee").Rows
Console.WriteLine("ID: {0}, FirstName: {1}, LastName: {2}", r("EmployeeID"), r("FirstName"), r("LastName"))
Next
Catch ex As Exception
" An error occurred. Show the error message
Console.WriteLine(ex.Message)
End Try
End Sub
End Class