Memodifikasi Data dengan DbDataAdapter
Metode CreateDataAdapter dari objek DbProviderFactory memberi Anda objek DbDataAdapter yang sangat digolongkan ke penyedia data yang mendasar yang ditentukan pada saat Anda membuat pabrik. Anda kemudian bisa menggunakan DbCommandBuilder untuk membuat perintah untuk menyisipkan, memperbarui, dan menghapus data dari DataSet ke sumber data.
Mengambil Data dengan DbDataAdapter
Contoh ini menunjukkan cara membuat yang diketik DbDataAdapter
dengan kuat berdasarkan nama penyedia dan string koneksi. Kode menggunakan CreateConnection metode DbProviderFactory untuk membuat DbConnection. Selanjutnya, kode menggunakan metode CreateCommand untuk membuat DbCommand untuk memilih data dengan mengatur properti CommandText
dan Connection
. Akhirnya, kode membuat objek DbDataAdapter menggunakan metode CreateDataAdapter dan mengatur properti SelectCommand
. Metode Fill
memuat DbDataAdapter
data ke dalam DataTable.
static void CreateDataAdapter(string providerName, string connectionString)
{
try
{
// Create the DbProviderFactory and DbConnection.
DbProviderFactory factory =
DbProviderFactories.GetFactory(providerName);
DbConnection connection = factory.CreateConnection();
connection.ConnectionString = connectionString;
using (connection)
{
// Define the query.
const string queryString =
"SELECT CategoryName FROM Categories";
// Create the DbCommand.
DbCommand command = factory.CreateCommand();
command.CommandText = queryString;
command.Connection = connection;
// Create the DbDataAdapter.
DbDataAdapter adapter = factory.CreateDataAdapter();
adapter.SelectCommand = command;
// Fill the DataTable.
DataTable table = new();
adapter.Fill(table);
// Display each row and column value.
foreach (DataRow row in table.Rows)
{
foreach (DataColumn column in table.Columns)
{
Console.WriteLine(row[column]);
}
}
}
}
catch (Exception ex)
{
Console.WriteLine(ex.Message);
}
}
Shared Sub CreateDataAdapter(ByVal providerName As String, _
ByVal connectionString As String)
' Create the DbProviderFactory and DbConnection.
Try
Dim factory As DbProviderFactory = _
DbProviderFactories.GetFactory(providerName)
Dim connection As DbConnection = _
factory.CreateConnection()
connection.ConnectionString = connectionString
Using connection
' Define the query.
Dim queryString As String = _
"SELECT CategoryName FROM Categories"
'Create the DbCommand.
Dim command As DbCommand = _
factory.CreateCommand()
command.CommandText = queryString
command.Connection = connection
' Create the DbDataAdapter.
Dim adapter As DbDataAdapter = _
factory.CreateDataAdapter()
adapter.SelectCommand = command
' Fill the DataTable
Dim table As New DataTable
adapter.Fill(table)
'Display each row and column value.
Dim row As DataRow
Dim column As DataColumn
For Each row In table.Rows
For Each column In table.Columns
Console.WriteLine(row(column))
Next
Next
End Using
Catch ex As Exception
Console.WriteLine(ex.Message)
End Try
End Sub
Memodifikasi Data dengan DbDataAdapter
Contoh ini menunjukkan cara memodifikasi data dalam DataTable
menggunakan DbDataAdapter dengan menggunakan untuk menghasilkan perintah yang DbCommandBuilder diperlukan untuk memperbarui data di sumber data. SelectCommand dari DbDataAdapter
diatur untuk mengambil CustomerID dan CompanyName dari tabel Pelanggan. Metode GetInsertCommand ini digunakan untuk mengatur properti InsertCommand, metode GetUpdateCommand digunakan untuk mengatur properti UpdateCommand, dan metode GetDeleteCommand digunakan untuk mengatur properti DeleteCommand. Kode menambahkan baris baru ke tabel Pelanggan dan memperbarui sumber data. Kode kemudian menempatkan baris yang ditambahkan dengan mencari di CustomerID, yang merupakan kunci utama yang ditentukan untuk tabel Pelanggan. Ini mengubah CompanyName dan memperbarui sumber data. Akhirnya, kode menghapus baris.
static void CreateDataAdapter(string providerName, string connectionString)
{
try
{
// Create the DbProviderFactory and DbConnection.
DbProviderFactory factory =
DbProviderFactories.GetFactory(providerName);
DbConnection connection = factory.CreateConnection();
connection.ConnectionString = connectionString;
using (connection)
{
// Define the query.
const string queryString =
"SELECT CustomerID, CompanyName FROM Customers";
// Create the select command.
DbCommand command = factory.CreateCommand();
command.CommandText = queryString;
command.Connection = connection;
// Create the DbDataAdapter.
DbDataAdapter adapter = factory.CreateDataAdapter();
adapter.SelectCommand = command;
// Create the DbCommandBuilder.
DbCommandBuilder builder = factory.CreateCommandBuilder();
builder.DataAdapter = adapter;
// Get the insert, update and delete commands.
adapter.InsertCommand = builder.GetInsertCommand();
adapter.UpdateCommand = builder.GetUpdateCommand();
adapter.DeleteCommand = builder.GetDeleteCommand();
// Display the CommandText for each command.
Console.WriteLine("InsertCommand: {0}",
adapter.InsertCommand.CommandText);
Console.WriteLine("UpdateCommand: {0}",
adapter.UpdateCommand.CommandText);
Console.WriteLine("DeleteCommand: {0}",
adapter.DeleteCommand.CommandText);
// Fill the DataTable.
DataTable table = new();
adapter.Fill(table);
// Insert a new row.
DataRow newRow = table.NewRow();
newRow["CustomerID"] = "XYZZZ";
newRow["CompanyName"] = "XYZ Company";
table.Rows.Add(newRow);
adapter.Update(table);
// Display rows after insert.
Console.WriteLine();
Console.WriteLine("----List All Rows-----");
foreach (DataRow row in table.Rows)
{
Console.WriteLine("{0} {1}", row[0], row[1]);
}
Console.WriteLine("----After Insert-----");
// Edit an existing row.
DataRow[] editRow = table.Select("CustomerID = 'XYZZZ'");
editRow[0]["CompanyName"] = "XYZ Corporation";
adapter.Update(table);
// Display rows after update.
Console.WriteLine();
foreach (DataRow row in table.Rows)
{
Console.WriteLine("{0} {1}", row[0], row[1]);
}
Console.WriteLine("----After Update-----");
// Delete a row.
DataRow[] deleteRow = table.Select("CustomerID = 'XYZZZ'");
foreach (DataRow row in deleteRow)
{
row.Delete();
}
adapter.Update(table);
// Display rows after delete.
Console.WriteLine();
foreach (DataRow row in table.Rows)
{
Console.WriteLine("{0} {1}", row[0], row[1]);
}
Console.WriteLine("----After Delete-----");
Console.WriteLine("Customer XYZZZ was deleted.");
}
}
catch (Exception ex)
{
Console.WriteLine(ex.Message);
}
}
Shared Sub CreateDataAdapter(ByVal providerName As String, _
ByVal connectionString As String)
' Create the DbProviderFactory and DbConnection.
Try
Dim factory As DbProviderFactory = _
DbProviderFactories.GetFactory(providerName)
Dim connection As DbConnection = _
factory.CreateConnection()
connection.ConnectionString = connectionString
Using connection
' Define the query.
Dim queryString As String = _
"SELECT CustomerID, CompanyName FROM Customers"
'Create the select command.
Dim command As DbCommand = _
factory.CreateCommand()
command.CommandText = queryString
command.Connection = connection
' Create the DbDataAdapter.
Dim adapter As DbDataAdapter = _
factory.CreateDataAdapter()
adapter.SelectCommand = command
' Create the DbCommandBuilder.
Dim builder As DbCommandBuilder = _
factory.CreateCommandBuilder()
builder.DataAdapter = adapter
' Get the insert, update and delete commands.
adapter.InsertCommand = builder.GetInsertCommand()
adapter.UpdateCommand = builder.GetUpdateCommand()
adapter.DeleteCommand = builder.GetDeleteCommand()
' Display the CommandText for each command.
Console.WriteLine("InsertCommand: {0}", _
adapter.InsertCommand.CommandText)
Console.WriteLine("UpdateCommand: {0}", _
adapter.UpdateCommand.CommandText)
Console.WriteLine("DeleteCommand: {0}", _
adapter.DeleteCommand.CommandText)
' Fill the DataTable
Dim table As New DataTable
adapter.Fill(table)
' Insert a new row.
Dim newRow As DataRow = table.NewRow
newRow("CustomerID") = "XYZZZ"
newRow("CompanyName") = "XYZ Company"
table.Rows.Add(newRow)
adapter.Update(table)
' Display rows after insert.
Console.WriteLine()
Console.WriteLine("----List All Rows-----")
Dim row As DataRow
For Each row In table.Rows
Console.WriteLine("{0} {1}", row(0), row(1))
Next
Console.WriteLine("----After Insert-----")
' Edit an existing row.
Dim editRow() As DataRow = _
table.Select("CustomerID = 'XYZZZ'")
editRow(0)("CompanyName") = "XYZ Corporation"
adapter.Update(table)
' Display rows after update.
Console.WriteLine()
For Each row In table.Rows
Console.WriteLine("{0} {1}", row(0), row(1))
Next
Console.WriteLine("----After Update-----")
' Delete a row.
Dim deleteRow() As DataRow = _
table.Select("CustomerID = 'XYZZZ'")
For Each row In deleteRow
row.Delete()
Next
adapter.Update(table)
table.AcceptChanges()
' Display each row and column value after delete.
Console.WriteLine()
For Each row In table.Rows
Console.WriteLine("{0} {1}", row(0), row(1))
Next
Console.WriteLine("----After Delete-----")
Console.WriteLine("Customer XYZZZ was deleted.")
End Using
Catch ex As Exception
Console.WriteLine(ex.Message)
End Try
End Sub
Parameter Penanganan
Penyedia data .NET Framework menangani penamaan dan menentukan parameter dan tempat penampung parameter secara berbeda. Sintaks ini disesuaikan dengan sumber data tertentu, seperti yang dijelaskan dalam tabel berikut.
Penyedia data | Sintaks penamaan parameter |
---|---|
SqlClient |
Menggunakan parameter bernama dalam format @ parametername. |
OracleClient |
Menggunakan parameter bernama dalam format : parmname (atau parmname). |
OleDb |
Menggunakan penanda parameter posisi yang ditunjukkan oleh tanda tanya (? ). |
Odbc |
Menggunakan penanda parameter posisi yang ditunjukkan oleh tanda tanya (? ). |
Model pabrik tidak membantu untuk membuat parameter DbCommand
dan DbDataAdapter
objek. Anda harus bercabang dalam kode Anda untuk membuat parameter yang disesuaikan dengan penyedia data Anda.
Penting
Menghindari parameter khusus penyedia sama sekali dengan menggunakan penggabungan string untuk membangun pernyataan SQL langsung tidak disarankan untuk alasan keamanan. Menggunakan penggabungan string alih-alih parameter membuat aplikasi Anda rentan terhadap serangan injeksi SQL.