Postgres has a special thing I don't understand.

[Danack]

Description

But this seems to be quite chaotic, reading
https://secure.php.net/manual/en/pdostatement.bindcolumn.php

"Since information about the columns is not always available to PDO
until the statement is executed, portable applications should call this
function after PDOStatement::execute().

However, to be able to bind a LOB column as a stream when using the
PgSQL driver, applications should call this method before calling
PDOStatement::execute(), otherwise the large object OID will be returned
as an integer."

[Danack]

Also:

Creating a LOB (Large Object) in PostgreSQL: PDO::pgsqlLOBCreate
Creating a function in SQLite: PDO::sqliteCreateFunction