我正在尝试从 CLR 存储过程访问 Sql 文件流。我已经建立了一个非常简单的数据库,其中包含一个包含文件流列的单个表。我可以使用一个简单的控制台应用程序成功地从文件流中读取。这是失败的proc的一些示例代码:
[SqlProcedure]
public static void GetDataFromFileStream(string path, out int data)
{
using (var connection = new SqlConnection("context connection=true"))
{
connection.Open();
var transaction = connection.BeginTransaction();
var transactionContext = GetTransactionContext(connection, transaction);
// the following line throws an exception
var sqlFileStream = new SqlFileStream(path, transactionContext, FileAccess.Read);
var buffer = new byte[4];
sqlFileStream.Read(buffer, 0, 4);
data = BitConverter.ToInt32(buffer, 0);
}
}
private static byte[] GetTransactionContext(SqlConnection connection, SqlTransaction transaction)
{
using (var cmd = connection.CreateCommand())
{
const string myGetTxContextQuery = "SELECT GET_FILESTREAM_TRANSACTION_CONTEXT()";
cmd.CommandText = myGetTxContextQuery;
cmd.CommandTimeout = 60;
cmd.CommandType = CommandType.Text;
cmd.Transaction = transaction;
return (byte[])cmd.ExecuteScalar();
}
}
尝试构造 SqlFileStream 实例时抛出异常:
System.ComponentModel.Win32Exception 发生 Message="不支持请求" Source="System.Data" ErrorCode=-2147467259 NativeErrorCode=50
有人知道我在做什么错吗?