带进度的SQL Server FileStream如何存取

-- =========================================================-- 启用 filestream_access_level-- =========================================================EXEC sp_configure 'filestream_access_level', 2; -- 0=禁用 1=针对 T-SQL 访问启用 FILESTREAM 2=针对 T-SQL 和 WIN32 流访问启用 FILESTREAMRECONFIGURE; GO-- =========================================================-- 创建测试数据库-- =========================================================EXEC master..xp_create_subdir 'f:\temp\db\_test';CREATE DATABASE _testON PRIMARY( NAME = _test, FILENAME = 'f:\temp\db\_test\_test.mdf'), FILEGROUP FG_stream CONTAINS FILESTREAM( NAME = _test_file_stream, FILENAME = 'f:\temp\db\_test\stream') LOG ON( NAME = _test_log, FILENAME = 'f:\temp\db\_test\_test.ldf') ;GO-- =========================================================-- FileStream-- =========================================================-- =================================================-- 创建 包含 FileStream 数据的表-- -------------------------------------------------CREATE TABLE _test.dbo.tb_fs( id uniqueidentifier ROWGUIDCOL -- 必需 DEFAULT NEWSEQUENTIALID ( ) PRIMARY KEY, name nvarchar(260), content varbinary(max) FILESTREAM );GO

下面的 VB 脚本实现带进度显示的文件存(Write方法）取（Read方法）

Imports System.IO Imports System Imports System.Collections.Generic Imports System.Text Imports System.Data Imports System.Data.SqlClient Imports System.Data.SqlTypes Module Module1 Public Sub Main(ByVal args As String()) Dim sqlConnection As New SqlConnection("Integrated Security=true;server=localhost") Try sqlConnection.Open() Console.WriteLine("将文件保存到 FileStream") Write(sqlConnection, "test", "f:\temp\re.csv") Console.WriteLine("从 FileStream 读取数据保存到文件") Read(sqlConnection, "test", "f:\temp\re_1.csv") Catch ex As System.Exception Console.WriteLine(ex.ToString()) Finally sqlConnection.Close() End Try Console.WriteLine("处理结束，按 Enter 退出") Console.ReadLine() End Sub ''' <summary> ''' 将文件保存到数据库 ''' </summary> ''' <param name="conn">数据库连接</param> ''' <param name="name">名称</param> ''' <param name="file">文件名</param> Sub Write(ByVal conn As SqlConnection, ByVal name As String, ByVal file As String) Dim bufferSize As Int32 = 1024 Using sqlCmd As New SqlCommand sqlCmd.Connection = conn '事务 Dim transaction As SqlTransaction = conn.BeginTransaction("mainTranaction") sqlCmd.Transaction = transaction '1. 读取 FILESTREAM 文件路径 ( 注意函数大小写 ) sqlCmd.CommandText = " UPDATE _test.dbo.tb_fs SET content = 0x WHERE name = @name; IF @@ROWCOUNT = 0 INSERT _test.dbo.tb_fs(name, content) VALUES( @name, 0x ); SELECT content.PathName() FROM _test.dbo.tb_fs WHERE name = @name;" sqlCmd.Parameters.Add(New SqlParameter("name", name)) Dim filePath As String = Nothing Dim pathObj As Object = sqlCmd.ExecuteScalar() If Not pathObj.Equals(DBNull.Value) Then filePath = DirectCast(pathObj, String) Else Throw New System.Exception("content.PathName() failed to read the path name for the content column.") End If '2. 读取当前事务上下文 sqlCmd.CommandText = "SELECT GET_FILESTREAM_TRANSACTION_CONTEXT()" Dim obj As Object = sqlCmd.ExecuteScalar() Dim txContext As Byte() = Nothing Dim contextLength As UInteger If Not obj.Equals(DBNull.Value) Then txContext = DirectCast(obj, Byte()) contextLength = txContext.Length() Else Dim message As String = "GET_FILESTREAM_TRANSACTION_CONTEXT() failed" Throw New System.Exception(message) End If '3. 获取 Win32 句柄，并使用该句柄在 FILESTREAM BLOB 中读取和写入数据 Using sqlFileStream As New SqlFileStream(filePath, txContext, FileAccess.Write) Dim buffer As Byte() = New Byte(bufferSize - 1) {} Dim numBytes As Integer = 0 Using fsRead As New FileStream(file, FileMode.Open) While True numBytes = fsRead.Read(buffer, 0, bufferSize) If numBytes = 0 Then Exit While sqlFileStream.Write(buffer, 0, numBytes) Console.WriteLine(String.Format("{0} -> {1} -> {2}", fsRead.Position, sqlFileStream.Position, numBytes)) End While fsRead.Close() End Using sqlFileStream.Close() End Using sqlCmd.Transaction.Commit() End Using End Sub ''' <summary> ''' 从数据库读取数据保存到文件 ''' </summary> ''' <param name="conn">数据库连接</param> ''' <param name="name">名称</param> ''' <param name="file">文件名</param> Sub Read(ByVal conn As SqlConnection, ByVal name As String, ByVal file As String) Dim bufferSize As Int32 = 1024 Using sqlCmd As New SqlCommand sqlCmd.Connection = conn '1. 读取 FILESTREAM 文件路径 ( 注意函数大小写 ) sqlCmd.CommandText = "SELECT content.PathName() FROM _test.dbo.tb_fs WHERE name = @name;" sqlCmd.Parameters.Add(New SqlParameter("name", name)) Dim filePath As String = Nothing Dim pathObj As Object = sqlCmd.ExecuteScalar() If Not pathObj.Equals(DBNull.Value) Then filePath = DirectCast(pathObj, String) Else Throw New System.Exception("content.PathName() failed to read the path name for the content column.") End If '2. 读取当前事务上下文 Dim transaction As SqlTransaction = conn.BeginTransaction("mainTranaction") sqlCmd.Transaction = transaction sqlCmd.CommandText = "SELECT GET_FILESTREAM_TRANSACTION_CONTEXT()" Dim obj As Object = sqlCmd.ExecuteScalar() Dim txContext As Byte() = Nothing Dim contextLength As UInteger If Not obj.Equals(DBNull.Value) Then txContext = DirectCast(obj, Byte()) contextLength = txContext.Length() Else Dim message As String = "GET_FILESTREAM_TRANSACTION_CONTEXT() failed" Throw New System.Exception(message) End If '3. 获取 Win32 句柄，并使用该句柄在 FILESTREAM BLOB 中读取和写入数据 Using sqlFileStream As New SqlFileStream(filePath, txContext, FileAccess.Read) Dim buffer As Byte() = New Byte(bufferSize - 1) {} Dim numBytes As Integer = 0 Using fsRead As New FileStream(file, FileMode.Create) While True numBytes = sqlFileStream.Read(buffer, 0, bufferSize) If numBytes = 0 Then Exit While fsRead.Write(buffer, 0, numBytes) Console.WriteLine(String.Format("{0} -> {1} -> {2}", sqlFileStream.Position, sqlFileStream.Position, numBytes)) End While fsRead.Close() End Using sqlFileStream.Close() End Using sqlCmd.Transaction.Commit() End Using End Sub End Module