c# oracle datareader,OracleDataReader

最新推荐文章于 2024-09-23 09:52:21 发布

弗兰克乙醚

最新推荐文章于 2024-09-23 09:52:21 发布

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文章标签： c# oracle datareader

本文档演示如何使用OracleDataReader类从Oracle数据库中读取数据。通过调用Read方法，可以逐行移动到数据集的下一条记录。示例代码展示了一个创建OracleConnection，OracleCommand，然后使用ExecuteReader获取数据的完整过程。数据读取后，将其输出到控制台。最后，关闭DataReader和Connection。确保在访问数据前先调用Read方法，并在完成读取后关闭DataReader。

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Advances the OracleDataReader to the next record.

public:

virtual bool Read();

public:

override bool Read();

public bool Read ();

public override bool Read ();

abstract member Read : unit -> bool

override this.Read : unit -> bool

Public Function Read () As Boolean

Public Overrides Function Read () As Boolean

如果存在更多行，则为 true；否则为 false。true if there are more rows; otherwise, false.

实现

示例

The following example creates an OracleConnection, an OracleCommand, and an OracleDataReader. 该示例将读取数据，并将其写出到控制台。The example reads through the data, writing it out to the console. Finally, the example closes the OracleDataReader, then the OracleConnection.

private static void ReadData(string connectionString)

{

string queryString = "SELECT OrderID, CustomerID FROM Orders";

using (OracleConnection connection = new OracleConnection(connectionString))

{

OracleCommand command = new OracleCommand(queryString, connection);

connection.Open();

OracleDataReader reader;

reader = command.ExecuteReader();

// Always call Read before accessing data.

while (reader.Read())

{

Console.WriteLine(reader.GetInt32(0) + ", " + reader.GetString(1));

}

// Always call Close when done reading.

reader.Close();

}

}Public Sub ReadData(ByVal connectionString As String)

Dim queryString As String = _

"SELECT OrderID, CustomerID FROM Orders"

Using connection As New OracleConnection(connectionString)

Dim command As New OracleCommand(queryString, connection)

connection.Open()

Dim reader As OracleDataReader

reader = command.ExecuteReader()

' Always call Read before accessing data.

While reader.Read()

Console.WriteLine(reader.GetInt32(0) & ", " & reader.GetString(1))

End While

' Always call Close when done reading.

reader.Close()

End Using

End Sub

注解

The default position of the OracleDataReader is prior to the first record. 因此，您必须调用 Read 以开始访问任何数据。Therefore, you must call Read to begin accessing any data.

OracleDataReader在任意给定时间，都可以打开多个。More than one OracleDataReader can be open at any given time.

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