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: 
Figured it out. Here is an example showing how to insert a bunch of binary objects into a table:

```
pqxx::connection conn( ... );
conn.prepare( "test", "INSERT INTO mytable( name, binfile ) VALUES ($1, $2)" );
pqxx::work work( conn );
for ( ... )
{
    std::string name = "foo";
    void * bin_data = ...; // obviously do what you need to get the binary data...
    size_t bin_size = 123; // ...and the size of the binary data

    pqxx::binarystring blob( bin_data, bin_size );
    pqxx::result r = work.prepared( "test" )( name )( blob ).exec();
}
work.commit();

```

Here is how to get the binary data back out of the database:

```
pqxx::result result = work.exec( "SELECT * FROM mytable" );
for ( const auto &row : result )
{
    pqxx::binarystring blob( row["binfile"] );
    void * ptr = blob.data();
    size_t len = blob.size();
    ...
}

```
Since this question is the top search result for inserting a BYTEA via libpqxx, here's another way to do it using a parameterized query, which is more appropriate if performing a single insert.

```
// Assuming pre-existing pqxx::connection c, void * bin_data, size_t bin_size...
pqxx::work txn(c);
pqxx::result res = txn.parameterized("INSERT INTO mytable(name, binfile) VALUES ($1, $2)")
                                    (name)
                                    (pqxx::binarystring(bin_data, bin_size))
                                    .exec();
txn.commit();

```

Note that the parameters should *not* be escaped with the `quote` or `esc` methods.

Also note that the accepted answer of using `pqxx::connection::prepare` causes the prepared query to exist for the entire lifetime of the connection. If the connection will be long-lasting and the prepared query is no longer needed, it should probably be deleted by calling `pqxx::connection::unprepare`.