Error while saving binary image from database to folder

Question

I need to retrieve an image from a database and save it to disk. In the database, the image is stored in binary format but datatype of the column is varchar(5000).

This is the code that I am using for retrieving the image and saving it to disk

public void CreateImageDataUsingDataReader_ForNetezzaDB()
{
        string strDbConn = string.Empty;
        string strImageFileName = string.Empty;
        string strImageData = string.Empty;
        string strImgSavePath = string.Empty;
        string strQuery = string.Empty;

        Byte[] byteImageData;
        MemoryStream stmImageData = new MemoryStream();
        Image saveImage;

        try
        {
            //---open the database connection
            strDbConn = ConfigurationSettings.AppSettings["NetezzaDBConnection"].ToString().Trim();
            OleDbConnection dbcon = new OleDbConnection(strDbConn);
            dbcon.Open();
            strQuery = "select name,signature_vod__c from sfb_call2_vod where signature_vod__c is not null  limit 10";
            OleDbCommand cmdSelect = new OleDbCommand(strQuery, dbcon);
            OleDbDataReader imageReader = cmdSelect.ExecuteReader();

            if (imageReader.HasRows)
            {
                while (imageReader.Read())
                {
                    strImageFileName = imageReader["name"].ToString().Trim();
                    strImageData = imageReader["signature_vod__c"].ToString().Trim();

                    stmImageData.Seek(0, SeekOrigin.Begin);
                    //converting string to byte array
                    byteImageData = Convert.FromBase64String(strImageData);
                    //---create Memory stremm from the Image Byte data                        
                    stmImageData.Write(byteImageData, 0, byteImageData.Length);
                    //--saving the image
                    //saveImage = Image.FromStream(stmImageData);
                    using (saveImage = Image.FromStream(stmImageData))
                    {
                        strImgSavePath = ConfigurationSettings.AppSettings["ImageSavePath"].ToString().Trim();
                        saveImage.Save(strImgSavePath + strImageFileName + ".png", System.Drawing.Imaging.ImageFormat.Png);   ///---error comes in this line                           
                    }
                }
            }
            imageReader.Close();
            dbcon.Close();
            stmImageData.Close();
            stmImageData = null;
        }
        catch (Exception ex)
        {
            throw new Exception("Error Occured in method CreateImageDataUsingDataReader " + ex.Message);
        }
}

but I keep getting an error:

A generic error occurred in GDI+.

Same code if I execute for SQL Server database it works fine but issue comes only with the Netezza database

Please help me resolve this issue

Remove your `try ... catch` clause, it is hiding errors. – Dour High Arch Nov 28 '12 at 20:22 — Dour High Arch, Nov 28 '12 at 20:22

score 0 · Answer 1 · answered Nov 28 '12 at 19:54

You mention that you store the binary image in a varchar column. This and the fact that it works on an other db technology makes it obious that you read different data back in the Netazza case.

I would suggest to setup a testproject where you persist the same image to the 2 different databases (netazza and mssql), read it back from both a do a bitwise comparison of the result either between the db results or between original and read from db.

I would be surprised if you get the same result and if I am right, you should probalaby consider to use a binary data type to persist the image data in your db backend.

Agreed - you should be saving them in binary form. Images tend to take up a lot of space anyway, and by base64 encoding them so you can get them in a varchar column you are adding 1/3rd to the size of each one. — Kevin, Nov 28 '12 at 20:35

Error while saving binary image from database to folder

1 Answers1