OleDbDataAdapter.DeleteCommand 属性
定义
获取或设置 SQL 语句或存储过程,用于从数据集中删除记录。Gets or sets an SQL statement or stored procedure for deleting records from the data set.
public:
property System::Data::OleDb::OleDbCommand ^ DeleteCommand { System::Data::OleDb::OleDbCommand ^ get(); void set(System::Data::OleDb::OleDbCommand ^ value); };
public System.Data.OleDb.OleDbCommand DeleteCommand { get; set; }
public System.Data.OleDb.OleDbCommand? DeleteCommand { get; set; }
[System.Data.DataSysDescription("DbDataAdapter_DeleteCommand")]
public System.Data.OleDb.OleDbCommand DeleteCommand { get; set; }
member this.DeleteCommand : System.Data.OleDb.OleDbCommand with get, set
[<System.Data.DataSysDescription("DbDataAdapter_DeleteCommand")>]
member this.DeleteCommand : System.Data.OleDb.OleDbCommand with get, set
Public Property DeleteCommand As OleDbCommand
属性值
在 OleDbCommand 过程中使用的 Update(DataSet),用以删除数据源中与 DataSet 中已删除的行相对应的记录。An OleDbCommand used during Update(DataSet) to delete records in the data source that correspond to deleted rows in the DataSet.
- 属性
示例
下面的示例创建一个 OleDbDataAdapter 并设置 SelectCommand 和 DeleteCommand 属性。The following example creates an OleDbDataAdapter and sets the SelectCommand and DeleteCommand properties. 假设您已经创建了一个 OleDbConnection 对象。It assumes that you have already created an OleDbConnection object.
public static OleDbDataAdapter CreateCustomerAdapter(
OleDbConnection connection)
{
OleDbDataAdapter dataAdapter = new OleDbDataAdapter();
OleDbCommand command;
OleDbParameter parameter;
// Create the SelectCommand.
command = new OleDbCommand("SELECT CustomerID FROM Customers " +
"WHERE Country = ? AND City = ?", connection);
command.Parameters.Add("Country", OleDbType.VarChar, 15);
command.Parameters.Add("City", OleDbType.VarChar, 15);
dataAdapter.SelectCommand = command;
// Create the DeleteCommand.
command = new OleDbCommand(
"DELETE * FROM Customers WHERE CustomerID = ?",
connection);
parameter = command.Parameters.Add(
"CustomerID", OleDbType.Char, 5, "CustomerID");
parameter.SourceVersion = DataRowVersion.Original;
dataAdapter.DeleteCommand = command;
return dataAdapter;
}
Public Shared Function CreateCustomerAdapter( _
connection As OleDbConnection) As OleDbDataAdapter
Dim dataAdapter As New OleDbDataAdapter()
Dim command As OleDbCommand
Dim parameter As OleDbParameter
' Create the SelectCommand.
command = New OleDbCommand("SELECT CustomerID FROM Customers " & _
"WHERE Country = ? AND City = ?", connection)
command.Parameters.Add("Country", OleDbType.VarChar, 15)
command.Parameters.Add("City", OleDbType.VarChar, 15)
dataAdapter.SelectCommand = command
' Create the DeleteCommand.
command = New OleDbCommand( _
"DELETE * FROM Customers WHERE CustomerID = ?", _
connection)
parameter = command.Parameters.Add( _
"CustomerID", OleDbType.Char, 5, "CustomerID")
parameter.SourceVersion = DataRowVersion.Original
dataAdapter.DeleteCommand = command
Return dataAdapter
End Function
注解
在过程中 Update ,如果未设置此属性,并且主键信息存在于中 DataSet ,则 DeleteCommand 可以在设置 SelectCommand 属性并使用时自动生成 OleDbCommandBuilder 。During Update, if this property is not set and primary key information is present in the DataSet, the DeleteCommand can be generated automatically if you set the SelectCommand property and use the OleDbCommandBuilder. 然后,将生成未设置的任何其他命令 OleDbCommandBuilder 。Then, any additional commands that you do not set are generated by the OleDbCommandBuilder. 此代逻辑要求密钥列信息存在于中 DataSet 。This generation logic requires key column information to be present in the DataSet. 有关详细信息,请参阅使用 CommandBuilders 生成命令。For more information, see Generating Commands with CommandBuilders.
当 DeleteCommand 分配给以前创建的时 OleDbCommand , OleDbCommand 不会克隆。When DeleteCommand is assigned to a previously created OleDbCommand, the OleDbCommand is not cloned. DeleteCommand维护对先前创建的对象的引用 OleDbCommand 。The DeleteCommand maintains a reference to the previously created OleDbCommand object.