OdbcDataAdapter.SelectCommand 属性
定义
重要
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获取或设置 SQL 语句或存储过程，用于选择数据源中的记录。
public:
property System::Data::Odbc::OdbcCommand ^ SelectCommand { System::Data::Odbc::OdbcCommand ^ get(); void set(System::Data::Odbc::OdbcCommand ^ value); };public System.Data.Odbc.OdbcCommand? SelectCommand { get; set; }public System.Data.Odbc.OdbcCommand SelectCommand { get; set; }member this.SelectCommand : System.Data.Odbc.OdbcCommand with get, setPublic Property SelectCommand As OdbcCommand属性值
OdbcCommand，在填充操作过程中用于从数据源选择记录以放置在 DataSet 中。
示例
以下示例创建 并 OdbcDataAdapter 设置 SelectCommand 和 InsertCommand 属性。 它假定你已创建对象 OdbcConnection 。
public static OdbcDataAdapter CreateDataAdapter(
OdbcConnection connection)
{
string selectCommand =
"SELECT CustomerID, CompanyName FROM Customers";
OdbcDataAdapter adapter = new OdbcDataAdapter(
selectCommand, connection);
adapter.MissingSchemaAction = MissingSchemaAction.AddWithKey;
// Create the Insert, Update and Delete commands.
adapter.InsertCommand = new OdbcCommand(
"INSERT INTO Customers (CustomerID, CompanyName) " +
"VALUES (?, ?)");
adapter.UpdateCommand = new OdbcCommand(
"UPDATE Customers SET CustomerID = ?, CompanyName = ? " +
"WHERE CustomerID = ?");
adapter.DeleteCommand = new OdbcCommand(
"DELETE FROM Customers WHERE CustomerID = ?");
// Create the parameters.
adapter.InsertCommand.Parameters.Add("@CustomerID",
OdbcType.Char, 5, "CustomerID");
adapter.InsertCommand.Parameters.Add("@CompanyName",
OdbcType.VarChar, 40, "CompanyName");
adapter.UpdateCommand.Parameters.Add("@CustomerID",
OdbcType.Char, 5, "CustomerID");
adapter.UpdateCommand.Parameters.Add("@CompanyName",
OdbcType.VarChar, 40, "CompanyName");
adapter.UpdateCommand.Parameters.Add("@oldCustomerID",
OdbcType.Char, 5, "CustomerID").SourceVersion =
DataRowVersion.Original;
adapter.DeleteCommand.Parameters.Add("@CustomerID",
OdbcType.Char, 5, "CustomerID").SourceVersion =
DataRowVersion.Original;
return adapter;
}
Public Function CreateDataAdapter( _
ByVal connection As OdbcConnection) As OdbcDataAdapter
Dim selectCommand As String = _
"SELECT CustomerID, CompanyName FROM Customers"
Dim adapter As OdbcDataAdapter = _
New OdbcDataAdapter(selectCommand, connection)
adapter.MissingSchemaAction = MissingSchemaAction.AddWithKey
' Create the Insert, Update and Delete commands.
adapter.InsertCommand = New OdbcCommand( _
"INSERT INTO Customers (CustomerID, CompanyName) " & _
"VALUES (?, ?)")
adapter.UpdateCommand = New OdbcCommand( _
"UPDATE Customers SET CustomerID = ?, CompanyName = ? " & _
"WHERE CustomerID = ?")
adapter.DeleteCommand = New OdbcCommand( _
"DELETE FROM Customers WHERE CustomerID = ?")
' Create the parameters.
adapter.InsertCommand.Parameters.Add( _
"@CustomerID", OdbcType.Char, 5, "CustomerID")
adapter.InsertCommand.Parameters.Add( _
"@CompanyName", OdbcType.VarChar, 40, "CompanyName")
adapter.UpdateCommand.Parameters.Add( _
"@CustomerID", OdbcType.Char, 5, "CustomerID")
adapter.UpdateCommand.Parameters.Add( _
"@CompanyName", OdbcType.VarChar, 40, "CompanyName")
adapter.UpdateCommand.Parameters.Add( _
"@oldCustomerID", OdbcType.Char, 5, "CustomerID").SourceVersion = _
DataRowVersion.Original
adapter.DeleteCommand.Parameters.Add( _
"@CustomerID", OdbcType.Char, 5, "CustomerID").SourceVersion = _
DataRowVersion.Original
Return adapter
End Function
注解
当 SelectCommand 分配给之前创建的 OdbcCommand时， OdbcCommand 不会克隆 。 相反， 维护 SelectCommand 对以前创建的 OdbcCommand 对象的引用。
如果未 SelectCommand 返回任何行，则不会向 DataSet添加任何表，并且不会引发异常。
