PostgreSQL \lo_import and how to get the resulting OID into an UPDATE command?

As your file resides on your local machine and you want to import the blob to a remote server, you have two options:

1) Transfer the file to the server and use the server-side function:

UPDATE speciesSET    speciesimages = lo_import('/path/to/server-local/file/zzz4.jpg')WHERE  species = 'ACAAC04';

2) Use the psql meta-command like you have it.

But you cannot mix psql meta commands with SQL-commands, that's impossible.
Use the psql variable :LASTOID in an UPDATE command that you launch immediately after the \lo_import meta command in the same psql session:

UPDATE speciesSET    speciesimages = :LASTOIDWHERE  species = 'ACAAC04';

To script that (works in Linux, I am not familiar with Windows shell scripting):

echo "\lo_import '/path/to/my/file/zzz4.jpg' \\\\ UPDATE species SET speciesimages = :LASTOID WHERE  species = 'ACAAC04';" | \psql -h 192.168.1.12 -p 5432 -d myDB -U my_admin

• \\ is the separator meta-command. You need to double the \, in a "" string, because the shell interprets one layer.
• \ before the newline is just the line continuation in Linux shells.

Alternative syntax (tested on Linux again):

psql -h 192.168.1.12 -p 5432 -d myDB -U my_admin << EOF\lo_import '/path/to/my/file/zzz4.jpg'UPDATE speciesSET    speciesimages = :LASTOIDWHERE  species = 'ACAAC04';EOF

After importing an image with this command:

\lo_import '$imagePath' '$imageName'

You can then find the description of the binary by querying the pg_catalog.pg_largeobject_metadata table which stores the oid value you need.

Ie:

"SELECT oid as `"ID`",pg_catalog.obj_description(oid, 'pg_largeobject') as `"Description`"FROM pg_catalog.pg_largeobject_metadata WHERE pg_catalog.obj_description(oid,'pg_largeobject') = '$image' limit 1 "

Here's how to do it if your field is type bytea.

\lo_import '/cygdrive/c/Users/Chloe/Downloads/Contract.pdf'update contracts set contract = lo_get(:LASTOID) where id = 77;

Use \lo_list and \lo_unlink after you import.