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一、将图片存入Oracle数据库
示例表NEWS的结构为：newsid number(10),title varchar2(100),image(blob)
方法1：利用OracleCommandBuilder类（该类用于自动生成用于协调 DataSet 的更改与关联的数据库的单表命令。）
Dim cn As New OracleConnection("data source=site;uid=gf;pwd=macro;")
cn.Open()
Dim da As New OracleDataAdapter("select * from news", cn)
Dim myCB As New OracleCommandBuilder(da)
Dim ds As New DataSet("news")
da.MissingSchemaAction = MissingSchemaAction.AddWithKey
Dim fs As Stream = File1.PostedFile.InputStream ''''File1为文件选择框，作为服务器控件使用
Dim mydata(fs.Length) As Byte
fs.Read(mydata, 0, fs.Length)
fs.Close()
da.Fill(ds, "news")
Dim myRow As DataRow = ds.Tables("news").NewRow
myRow("newsid") = txtNewsID.Text
myRow("title") = txtTitle.Text
myRow("image") = mydata
ds.Tables("news").Rows.Add(myRow)
da.Update(ds, "news")
cn.Close()
方法2：利用过程
事先定义的Oracle过程为：
CREATE OR REPLACE PROCEDURE "GF"."NEWS_ADD"
(in_newsid in
news.newsid%type,
in_title in news.title%type,
in_imag in news.image%type)
as
begin
insert into gf.news values(in_newsid,in_title,in_image);
end;
下面是将数据存入数据库的代码：
Dim cn As New OracleConnection("data source=site;uid=gf;pwd=macro;")
cn.Open()
Dim cmd As New OracleCommand("news_add", cn)
cmd.CommandType = CommandType.StoredProcedure
cmd.Parameters.Add(New OracleParameter("in_newsid", OracleType.Number, 10))
cmd.Parameters("in_newsid").Value = txtNewsID.Text.Trim
cmd.Parameters.Add(New OracleParameter("in_title", OracleType.VarChar, 100))
cmd.Parameters("in_title").Value = txtTitle.Text.Trim
Dim fs As Stream = File1.PostedFile.InputStream
Dim mydata(fs.Length) As Byte ''''定义一个字节数组用于读取图片流
fs.Read(mydata, 0, fs.Length)
fs.Close()
cmd.Parameters.Add(New OracleParameter("in_image", OracleType.Blob))
cmd.Parameters("in_image").Value = mydata
cmd.ExecuteNonQuery()
cn.Close()
二、从Oracle数据库中读出图片
方法1：从数据库中读取数据并以文件形式保留在服务器上
Dim conn As New OracleClient.OracleConnection
Dim cmd As New OracleClient.OracleCommand
Dim myReader As OracleClient.OracleDataReader
Dim sql As String
Dim fl As File
sql = "select * from news where newsid=3211" ''''从数据库中取出图片数据 blob
conn.ConnectionString = "Password=macro;User ID=gf;Data Source=site"
cmd.CommandText = sql
cmd.Connection = conn
conn.Open()
myReader = cmd.ExecuteReader(CommandBehavior.SequentialAccess)
myReader.Read()
Label1.Text = myReader("title")
Dim fs As FileStream '''' Writes the BLOB to a file (*.bmp).
Dim bw As BinaryWriter '''' Streams the binary data to the FileStream object.
Dim bufferSize As Integer = 1000 '''' The size of the BLOB buffer.
Dim outbyte(bufferSize - 1) As Byte '''' The BLOB byte() buffer to be filled by GetBytes.
Dim retval As Long '''' The bytes returned from GetBytes.
Dim startIndex As Long = 0 '''' The starting position in the BLOB output.
Dim fpath As String
''''将图片数据存成本地文件
fpath = Server.MapPath(Request.ApplicationPath) & "\Image\photo.bmp"
fs = New FileStream(fpath, FileMode.OpenOrCreate, FileAccess.Write)
bw = New BinaryWriter(fs)
'''' Reset the starting byte for a new BLOB.
startIndex = 0
'''' Read bytes into outbyte() and retain the number of bytes returned.
retval = myReader.GetBytes(2, startIndex, outbyte, 0, bufferSize) ''''GetBytes返回字段中的可用字节数,第一个参数为从0开始的列序号
'''' Continue reading and writing while there are bytes beyond the size of the buffer.
Do While retval = bufferSize
bw.Write(outbyte)
bw.Flush() ''''清理当前编写器的所有缓冲区，使所有缓冲数据写入基础设备。
'''' Reposition the start index to the end of the last buffer and fill the buffer.
startIndex = startIndex + bufferSize
retval = myReader.GetBytes(2, startIndex, outbyte, 0, bufferSize)
Loop
'''' Write the remaining buffer.
bw.Write(outbyte)
bw.Flush()
'''' Close the output file.
bw.Close()
fs.Close()
'''' Close the reader and the connection.
myReader.Close()
conn.Close()
Dim logo As Image ''''文件格式转换
logo = Image.FromFile(fpath)
fpath = Server.MapPath(Request.ApplicationPath) & "\Image\zkjhy.jpeg"
logo.Save(fpath, System.Drawing.Imaging.ImageFormat.Jpeg)
''''Me.Image1.Width = New Unit(300) ''''调整显示大小
''''Me.Image1.Height = New Unit(350)
Me.Image1.ImageUrl = "image/zkjhy.jpeg"
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