Reading and writing BLOB in ADO.NET

Often you may need to save user images in a database and then read back from a database when needed. For an example, we’ll save an author’s photo in a database so it can be read later to display in the author’s article. In this article, you will learn how to read and write BLOB data using ADO.NET.

Mahesh Chand

Sep 21, 2003 · Updated Jan 19, 200667.3k80100Article

The text of this article is not in this database — only its details are. The old site it was published on is gone, but the Internet Archive kept a copy: Reading and writing BLOB in ADO.NET

8 Comments

Join the conversation! Your thoughts help the community grow.

pavan soni17y ago
df
- Mahesh Chand17y ago
  Please do not post unnecessary comments.
simon yong18y ago
Sir, Can you tell me what is the function of this: adapter.MissingSchemaAction = MissingSchemaAction.AddWithKey
- Mahesh Chand17y ago
  Read here: http://msdn.microsoft.com/en-us/library/49z48hxc(VS.71).aspx
Boris Aro19y agoedited
Hello! I work with VS2005. I have an Access Table, that has OLE Object as a field. The object may be a pointer to jpg, doc or xml file. Just in case jpg file I need to show it, in other case open it. I did next (not full code): Dim ms AsNew MemoryStream() Dim reader As OleDbDataReader = cmd.ExecuteReader(CommandBehavior.SequentialAccess ) reader.Read() retval = reader.GetBytes(0, 0, outbyte, 0, bufferSize) ms.Write(outbyte, 0, retval) ms.Seek(0, SeekOrigin.Begin) curImage = Image.FromStream(ms,False)----> error "Parameter is not valid." I do not see the fault. Please help
- Boris Aro19y ago
  Thank You so much for Your response. I find ab error in SQL, but I have a problem: "Parameter is not valid." Please try to help. I may see gotten data. I have an OLE Object in my table, that may be jpg, doc, xml file. In case of jpg I'd like to show it (VS2005 Visual basic). I did next (not full code): Dim ms AsNew MemoryStream() Dim reader As OleDbDataReader = cmd.ExecuteReader(CommandBehavior.SequentialAccess ) reader.Read() retval = reader.GetBytes(0, 0, outbyte, 0, bufferSize) ms.Write(outbyte, 0, retval) ms.Seek(0, SeekOrigin.Begin) curImage = Image.FromStream(ms,False)----> error "Parameter is not valid." I do not see the fault. Please help
- Mahesh Chand19y ago
  Are you getting any data back? You will get this error if there is no data returned. I would say Debug your code and see if data is coming back.
- Mahesh Chand19y agoedited
  Is your ms object "Nothing"? Debug it and check it. What version of .NET are you using? It is possible in .NET 2.0, method is changed a little. You will have to see MSDN documentation. I believe this article was written using .NET 1.0.