Syncing BLOB results in 0 byte file

Question

Hello, I have a custom VB program that scans a driver's license. The face image and text are then saved to the OLite client DB. However, when I sync to the server, the BLOB field is 0 bytes in the target table.
I have based the handling of the BLOB in my program on the BLOB sample code that is delivered with the Oracle Lite sample code <ora lite home>\mobile\sdk\samples\ado.net\win32\blob. When I run that code, it writes to the mobile client DB and then re-queries the BLOB, as it should. In order to test this with the sync, I then modified that sample code so that it writes the BLOB to my own table rather than the sample table. I then run msync, and it is also 0 bytes on the server. Is this some bug or maybe some setup that is missing? The code below is the section that handles the BLOB inserting and reading. I hope someone can help ... thanks in advance!
ryan
++++++++++++++++++++++++++++++++++++++
Private Sub Run()
Dim conn As OracleConnection
' Create Database
SetDone(lblCreate, False)
' Open database connection
Dim dsn As String = "dsn=IDMAN32_" & "emready;uid=system;pwd=IDMAN32"
conn = New Oracle.DataAccess.Lite.OracleConnection(dsn)
conn.Open()
SetDone(lblCreate, True)
' Create a table with a blob column
Dim cmd As IDbCommand
Dim blob As OracleBlob
SetDone(lblTable, False)
cmd = conn.CreateCommand()
' Create new BLOB object in polite database
SetDone(lblInsert, False)
blob = New OracleBlob(conn)
'Read data from the image file and write it into the blob
'in chunks
Dim file As FileStream
Dim browse As System.Windows.Forms.OpenFileDialog = New System.Windows.Forms.OpenFileDialog
browse.Filter = "Bitmap (*.bmp)|*.bmp|Gif (*.gif)|*.gif"
browse.Title = "Choose an Image File"
browse.ShowDialog()
Dim imageSrc As String = browse.FileName
Dim imageDes As String = "tmp.gif"
If imageSrc Is Nothing Or imageSrc.Length = 0 Then
imageSrc = "oracle.gif"
End If
file = New FileStream(imageSrc, FileMode.Open, FileAccess.Read)
Dim ImageData As Byte()
ReDim ImageData(file.Length)
Dim ArraySize As Integer = New Integer()
ArraySize = System.Convert.ToInt32(file.Length)
file.Read(ImageData, 0, ArraySize)
file.Close()
' Insert our image blob into the table using LiteParameter
cmd.CommandText = "insert into EMPLOYEE_STAGING (EMPLOYEE_ID, PHOTO) values(11000, ?)"
cmd.Parameters.Add(New OracleParameter("Image", blob))
cmd.ExecuteNonQuery()
cmd.Parameters.Clear()
conn.Commit() ' Commit transaction
SetDone(lblInsert, True)
' Read blob from the Database and write to a temp file
SetDone(lblRead, False)
Dim reader As IDataReader
cmd.CommandText = "select EMPLOYEE_ID, PHOTO from EMPLOYEE_STAGING WHERE EMPLOYEE_ID=11000"
reader = cmd.ExecuteReader()
If reader.Read() = False Then
cmd.Dispose()
conn.Close()
Throw New Exception("Failed to read blob")
End If
blob = reader.GetValue(1)
reader.Close()
file = New FileStream(imageDes, FileMode.Create, FileAccess.Write)
file.Write(ImageData, 0, ArraySize)
file.Close()
' Close database connection
conn.Close()
SetDone(lblRead, True)
' Display bitmap
Dim bmp As Bitmap
bmp = New Bitmap(imageDes)
bmpBox.Image = bmp
End Sub

Answer 1

Oracle just posted a sample today as well.
Caution
This sample code is provided for educational purposes only and not supported by Oracle Support Services. It has been tested internally, however, and works as documented. We do not guarantee that it will work for you, so be sure to test it in your environment before relying on it.
Proofread this sample code before using it! Due to the differences in the way text editors, e-mail packages and operating systems handle text formatting (spaces, tabs and carriage returns), this sample code may not be in an executable state when you first receive it. Check over the sample code to ensure that errors of this type are corrected.
Sample Code
Create the Oracle Lite Database
1. Create a new folder c:\ClobTest.
2. Open a Command Prompt.
3. Issue the command CREATEDB ClobTest c:\ClobTest\ClobTest.odb test.
4. Exit the command prompt.
Create the ODBC Data Source Name
1. Open the ODBC Data Source Administrator.
Start, run, odbcad32.exe.
2. Under either User DSN or System DSN, click Add.
3. Select Oracle Lite 40 ODBC Driver and click Finish.
4. Enter the following configuration information:
Data Source Name: ClobTest
Data Description: Clob Test Database
Database Directory: C:\ClobTest
Database: ClobTest
Default Isolation Level: Read Committed
Autocommit: Off
Default Cursor Type: Forward Only
5. Click OK and close the ODBC Data Source Administrator.
Create Oracle Database Lite Table
1. Open a Command Prompt.
2. Connect to the ClobTest Database with mSQL.
msql system/Test@jdbc:polite:ClobTest.
3. Create the TEST_CLOB table.
create table TEST_CLOB(
field1 VARCHAR2(60) PRIMARY KEY,
text CLOB);
commit;
4. Exit msql and exit the Command Prompt.
Create the Visual Studio 2005 C# ClobTest Project
1. Launch Visual Studio 2005.
2. Select Create Project.
3. Select the Visual C# Language and Windows for the project type, select the Windows Application template, name the project ClobTest, and click OK.
Reference the Oracle Database Lite ADO.Net 2.0 provider
1. Select Project, Add Reference.
2. Select the Browse tab.
3. Navigate to the <Olite SDK Home>\Mobile\Sdk\ado.net\v2.x direcotry.
4. Highlight Oracle.DataAccess.Lite_w32.dll file and click OK.
Create the ADO.Net ClobTest Application
1. Add the following class declarations to the declarations already contained by default:
using System.IO;
using Oracle.DataAccess.Lite;
using Oracle.Lite.Data;
using System.Diagnostics;
2. Declare a LiteConnection object in class scope.
LiteConnection con;
3. Instantiate the connection object in the Form_Load method.
con = new LiteConnection("DataDirectory=C:\\ClobTest;Database=ClobTest;DSN=*;uid=system;pwd=test");
4. Create a button object named cmdInsert wtih a text property of Insert.
5. Add the following code to the cmdInsert_Click method:
LiteCommand cmd = new LiteCommand(con);
byte[] buffer = new byte[5];
long lngOffset = 0;
try
con.Open();
Debug.Print("Connection Open");
LiteLob clobText = new LiteLob(con);
buffer = Encoding.UTF8.GetBytes("Smile");
//Clob Max = 2000000000 so with 5 max setting should be 400000000)
while(lngOffset < 400)
clobText.SetBytes(lngOffset, buffer, 0, 5);
lngOffset += 5;
cmd.CommandText = "INSERT INTO TEST_CLOB VALUES('Record 1', ?)";
cmd.Parameters.Add(new LiteParameter("text", clobText));
cmd.ExecuteNonQuery();
cmd.Parameters.Clear();
con.Commit();
MessageBox.Show("Clob Successfully Inserted", "Done");
catch (Exception ex)
Debug.Print(ex.Message);
finally
if (con.Connection.State == ConnectionState.Open)
con.Close();
Debug.Print("Connection Closed");
6. Create a button object named cmdRetrieve wtih a text property of Retrieve.
7. Add the following code to the cmdRetrieve_Click method:
LiteCommand cmd = new LiteCommand(con);
IDataReader dr;
FileStream file;
byte[] buffer = new byte[256];
long lngOffset = 0;
long chunk;
try
con.Open();
Debug.Print("Connection Open");
cmd.CommandText = "SELECT * FROM TEST_CLOB WHERE FIELD1 = 'Record 1'";
dr = cmd.ExecuteReader();
dr.Read();
LiteLob clobText = new LiteLob(con);
clobText = (LiteLob)dr["TEXT"];
file = new FileStream("c:\\ClobTest\\Retrieve.txt", FileMode.Create);
Debug.Print("Text File Created");
do
chunk = clobText.GetBytes(lngOffset, buffer, 0, 256);
file.Write(buffer, 0, (int)chunk);
lngOffset += chunk;
while (chunk != 0);
file.Close();
Debug.Print("Text File Closed");
MessageBox.Show("Clob Successfully Retrieved", "Done");
catch (Exception ex)
Debug.Print(ex.Message);
finally
if (con.Connection.State == ConnectionState.Open)
con.Close();
Debug.Print("Connection Closed");
Compile and test the sample
1. Select the Debug menu and choose Start Debugging.
2. Click on the Insert button to insert Clob data into the Oracle Lite database. The size of the Clob data may be altered by changing the while loop while(lngOffset < 400) to use a larger value.
3. Click on the Retrieve button to retrieve the Clob data from the database and write it as a new file.
4. Verify that the Retrieve.txt file is created in the c:\ClobTest folder and that the text may be viewed
correctly.