OracleDataReader returning empty byte array for BLOB column

Question

I'm attempting to retrieve a certificate stored as a BLOB in an Oracle database but I keep getting an empty byte array back. Here's a code snippet:

        OracleCommand command = new OracleCommand(QUERY_GETURLS, connection);

        OracleDataReader reader = null;

        try
        {
            connection.Open();
            reader = command.ExecuteReader();

            while (reader.Read())
            {
                string organization = reader["Organization"].ToString();
                string type = reader["Type"].ToString();
                string url = reader["DestinationUrl"].ToString();
                byte[] certificate = (byte[])reader["Certificate"];

Organization, type and URL are returned fine, but the certificate field always returns an empty byte array. If I manually run the same query against the database, the BLOB column is returned. The column data type is a LONG RAW and I am using ODP.NET.

have you looked at the OracleDataType mappings here msdn.microsoft.com/en-us/library/yk72thhd%28v=vs.110%29.aspx — MethodMan
– MethodMan, Commented Mar 25, 2015 at 17:55
OracleDataReader reader perhaps a BinaryReader would work or take a look at this link devart.com/dotconnect/oracle/articles/lob.html — MethodMan
– MethodMan, Commented Mar 25, 2015 at 17:57
@MethodMan thanks for that. I found the ODP.NET version of that page here docs.oracle.com/cd/B28359_01/win.111/b28375/featTypes.htm and they state I need to use an OracleBinary if my column type is LONG RAW. I think I need to change my column to a BLOB and use a byte array. — farbodg
– farbodg, Commented Mar 25, 2015 at 18:06
that's good assuming you can change the data type of the column with already loaded data.. which you should be able to do.. glad you were able to find a viable solution "+1" — MethodMan
– MethodMan, Commented Mar 25, 2015 at 18:17

farbodg · Accepted Answer · 2015-03-25 18:25:42Z

1

Thanks to MethodMan, I was able to find the appropriate page that shows what data types to use for ODP.NET:

docs.oracle.com/cd/B28359_01/win.111/b28375/featTypes.htm

I can use an OracleBinary for a LONG RAW. After further research, it seems that the Oracle community is going away from LONG RAW and towards a BLOB. I am going to switch my column data type to BLOB and use a byte array.

edited Mar 25, 2015 at 18:25

answered Mar 25, 2015 at 18:19

farbodg

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1 Comment

Shaurav Adhikari Over a year ago

But how do you rad the byte[] in .net. I am getting [0] all the time?

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