firebird-net-provider

[Firebird-net-provider] Storing Binary Data (not in a blob)

[Christopher W. <chr...@ad...>]

Hello,

I am attempting to use the Firebird Net-Provider to store binary data
that can be included in a where clause.  I am modifying code that works
on MS SQL Server where the column is varbinary with a length of 4096. 
If I use a blob subtype binary, NetProvider works fine on the insert,
but I also want to be able to delete rows based on the value contained
in the binary data.  Someone please correct me if I am wrong, but the
firebird blob seems only for storage and retrieval and it does not
appear you can use it as a column in the where clause...

I researched it a bit on the web and I have seen the recommendation to
store binary data by using char(size) character set octets.  Apparently,
firebird won't perform any transliteration on the data and stores it in
its native binary format.  I have tried this solution using the
Net-Provider two different ways and in both cases it throws an Invalid
Cast exception.  I tried setting the FbType of the parameter to Char and
also setting it to Binary...

I was also wondering if I should use C# to somehow transform the byte[]
into a string representing the binary information...

Any suggestions on how to solve this problem would be greatly
appreciated.  

Regards,

Chris Whelan

[Firebird-net-provider] Re:Storing Binary Data (not in a blob)

[Christopher W. <chr...@ad...>]

Hi-

I also tried FbType of LongVarBinary which I had used successfully for
the blob insertion and I still receive a Invalid Cast exception...

Regards,

Chris Whelan

[Firebird-net-provider] Re:Storing Binary Data (not in a blob)

[Christopher W. <chr...@ad...>]

Hi-

FYI to anyone interested:

It doesn't seem that efficient, but I solved the problem by iterating
over the byte[] contents in a loop and appending the result of
(char)byte[i] to a StringBuilder instance.  I set the FBType of the
parameter to Char and write the string to the database without a
problem.  I also write the actual length of the data to another column
because it represents a serialized object and must be deserialized into
an instance.  

The column that is defined as char(x) character set octets does allow
the delete statement that uses it in the where clause to work properly.

When I get the results of the select, I need to transform the string
representing the binary data into the datatable column format of
Base64Binary.  That rules out dataAdapter.Fill( dateSet ).  Instead  I
used the following code to load the data from the database table into
the dataset:

                FbDataReader reader =
m_daSinks.SelectCommand.ExecuteReader();

                byte[] buff1, buff2;
                while( reader.Read() )
                {

                    buff1 = ASCIIEncoding.Default.GetBytes(
reader.GetString( 0 ) );  // Binary data is in first column

                    buff2 = new byte[ reader.GetInt16( 1 )];    //
Actual Length of the binary data

                    Array.Copy( buff1, 0, buff2, 0, buff2.Length );

                    object[] vals = new Object[]{ reader.GetInt64(2),
buff2, DateTime.Now, EventName };
                    ds.Tables["tb_sinks"].LoadDataRow( vals, true );
                }

                reader.Close();


Any suggestions for improving this approach would be greatly
appreciated.

Regards,

Chris Whelan

Re: [Firebird-net-provider] Re:Storing Binary Data (not in a blob)

[Carlos G. A. <car...@te...>]

Hello:

> It doesn't seem that efficient, but I solved the problem by iterating 
> over the byte[] contents in a loop and appending the result of 
> (char)byte[i] to a StringBuilder instance.  


Why do not try using Encoding.Default.GetString(...) ???

> 
>                 FbDataReader reader = 
> m_daSinks.SelectCommand.ExecuteReader();
> 
>                 byte[] buff1, buff2;
>                 while( reader.Read() )
>                 {
> 
>                     buff1 = ASCIIEncoding.Default.GetBytes( 
> reader.GetString( 0 ) );  // Binary data is in first column
> 
>                     buff2 = new byte[ reader.GetInt16( 1 )];    // 
> Actual Length of the binary data
> 
>                     Array.Copy( buff1, 0, buff2, 0, buff2.Length );
> 
>                     object[] vals = new Object[]{ reader.GetInt64(2), 
> buff2, DateTime.Now, EventName };
>                     ds.Tables["tb_sinks"].LoadDataRow( vals, true );
>                 }
> 
>                 reader.Close();


Huummmm ... anything like this


	int bufLen = 0;
	byte[] buff1, buff2;
	while( reader.Read() )
	{
		buff1 = new byte[reader.GetInt16( 1 )]
		// Use here the encoding you need
		Endcoding.Default.GetBytes(
		reader.GetString( 0 ), 0, buff1.Length, buff1, 0 );

		object[] vals = new Object[]{ reader.GetInt64(2),
				buff2, DateTime.Now, EventName };
		ds.Tables["tb_sinks"].LoadDataRow( vals, true );
	}





-- 
Best regards

Carlos Guzmán Álvarez
Vigo-Spain

"No tengo dones especiales.Sólo soy apasionadamente curioso"
Albert Einstein, científico.

Re: [Firebird-net-provider] Re:Storing Binary Data (not in a blob)

[Christopher W. <chr...@ad...>]

I'll try that...Thanks!


On Thu, 2003-05-29 at 13:47, Carlos Guzman Alvarez wrote:
> Hello:
> 
> > It doesn't seem that efficient, but I solved the problem by iterating 
> > over the byte[] contents in a loop and appending the result of 
> > (char)byte[i] to a StringBuilder instance.  
> 
> 
> Why do not try using Encoding.Default.GetString(...) ???
> 
> > 
> >                 FbDataReader reader = 
> > m_daSinks.SelectCommand.ExecuteReader();
> > 
> >                 byte[] buff1, buff2;
> >                 while( reader.Read() )
> >                 {
> > 
> >                     buff1 = ASCIIEncoding.Default.GetBytes( 
> > reader.GetString( 0 ) );  // Binary data is in first column
> > 
> >                     buff2 = new byte[ reader.GetInt16( 1 )];    // 
> > Actual Length of the binary data
> > 
> >                     Array.Copy( buff1, 0, buff2, 0, buff2.Length );
> > 
> >                     object[] vals = new Object[]{ reader.GetInt64(2), 
> > buff2, DateTime.Now, EventName };
> >                     ds.Tables["tb_sinks"].LoadDataRow( vals, true );
> >                 }
> > 
> >                 reader.Close();
> 
> 
> Huummmm ... anything like this
> 
> 
> 	int bufLen = 0;
> 	byte[] buff1, buff2;
> 	while( reader.Read() )
> 	{
> 		buff1 = new byte[reader.GetInt16( 1 )]
> 		// Use here the encoding you need
> 		Endcoding.Default.GetBytes(
> 		reader.GetString( 0 ), 0, buff1.Length, buff1, 0 );
> 
> 		object[] vals = new Object[]{ reader.GetInt64(2),
> 				buff2, DateTime.Now, EventName };
> 		ds.Tables["tb_sinks"].LoadDataRow( vals, true );
> 	}
> 
> 
> 
>