小编给大家分享一下怎么存取带进度的SQL Server FileStream，相信大部分人都还不怎么了解，因此分享这篇文章给大家参考一下，希望大家阅读完这篇文章后大有收获，下面让我们一起去了解一下吧！
SQL Server FileStream 功能的详细参考联机帮助设计和实现 FILESTREAM 存储
这里只是把使用 Win32 管理 FILESTREAM 数据的代码调整了一下，实现带进度的存取，这对于存取较大的文件比较有意义
要使用FileStream，首先要在 SQL Server配置管理器中打开FileStream选项：SQL Server配置管理器–SQL Server服务–右边的服务列表中找到SQL Server服务–属性–FILESTREAM–允许远程客户端访问FILESTREAM数据根据需要选择，其他两荐都选上。配置完成后，需要重新启动SQL Server服务使设置生效。
然后使用下面的脚本创建测试数据库和测试表
-- =========================================================-- 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以上是怎么存取带进度的SQL Server FileStream的所有内容，感谢各位的阅读！相信大家都有了一定的了解，希望分享的内容对大家有所帮助，如果还想学习更多知识，欢迎关注亿速云行业资讯频道！
