Question: I'd like to insert some binary data into a BYTEA column, but I find the Doxygen output is lacking in details, and <http://pqxx.org/> has been down for the past few days.

How would I go about inserting the contents of somefile.bin into a table with a BYTEA column?

What I have is along these lines:

```
pqxx::work work( conn );
work.exec( "CREATE TABLE test ( name varchar(20), data BYTEA )" );
work.exec( "INSERT INTO test( name, data ) VALUES ( 'foo', <insert filename.bin here> )" );
work.commit();

```

If it makes a difference, I'd like to use the new `hex` format for BYTEA available in PostgreSQL 9.1.

Answer: 
There is not pqxx::bynarystring in insertion. I used the following solution to do that:

=== STORING AN wxImage IN DATABASE ====  

```
//Getting image string data
wxImage foto = (...);
wxMemoryOutputStream stream;
foto.SaveFile(stream,wxBITMAP_TYPE_PNG);
wxStreamBuffer* streamBuffer = stream.GetOutputStreamBuffer();
size_t tamanho = streamBuffer->GetBufferSize();
char* fotoData = reinterpret_cast<char*>(streamBuffer->GetBufferStart());
string dados(fotoData, tamanho);

//Performing the query
conn->prepare("InsertBinaryData", "INSERT INTO table1(bytea_field) VALUES (decode(encode($1,'HEX'),'HEX'))") ("bytea",pqxx::prepare::treat_binary);

pqxx::work w = (...);
w.prepared(dados).exec();

```

=== RETRIEVING AN wxImage FROM DATABASE ====   

```
pqxx::result r = w.exec("SELECT bytea_field FROM table1 WHERE (...)");
w.commit();

const result::tuple row = r[0];
const result::field tfoto = row[0];

pqxx::binarystring bs(tfoto);
const char* dadosImg = bs.get();
size_t size = bs.length();

wxMemoryInputStream stream(dadosImg,size);
wxImage imagem;

imagem.LoadFile(stream);

```

I hope it be helpfull.
I've come up with a flexible solution using binary data inside `std::string`. 

I propose this new solution because current answers are old (2013) and I was looking for a multi insert query using pqxx 5.0.1. 

With the solution bellow you have the flexibility to use a `for loop` to append multiple binary data in a single insert query. 

```
CustomStruct data = .... ; // have some binary data

// initialise connection and declare worker
pqxx::connection conn = new pqxx::connection(...);    
pqxx::work w(conn); 

// prepare query
string query += "INSERT INTO table (bytea_field) VALUES ("
// convert your data in a binary string. 
pqxx::binarystring blob((void *)&(data), data.size());
// avoid null character to bug your query string. 
query += "'"+w.esc_raw(blob.str())+"');";

//execute query
pqxx::result rows = w.exec(query);

```

When we want to retrieve data from the database you should have the scope of your datatype (`CustomStruct` for instance) and you should be able to cast it back in the binary format of your choice.

```
// assuming worker and connection are declared and initialized.
string query = "SELECT bytea_field FROM table;";
pqxx::result rows = w.exec(query);
for(pqxx::result::iterator col = rows.begin(); col != rows.end(); ++col)
{
    pqxx::binarystring blob(col[0]);
    CustomStruct *data = (CustomStruct*) blob.data();
    ...
}

```

This was tested with `pqxx 5.0.1`, `c++11` and `postgresSQL 9.5.8`