PostgreSQL 7.4.11 Documentation
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# 28.4. Server-Side Functions

There are two built-in server-side functions, `lo_import` and `lo_export`, for large object access, which are available for use in SQL commands. Here is an example of their use:

    CREATE TABLE image (
        name            text,
        raster          oid
    );

    INSERT INTO image (name, raster)
        VALUES ('beautiful image', lo_import('/etc/motd'));

    SELECT lo_export(image.raster, '/tmp/motd') FROM image
        WHERE name = 'beautiful image';

These functions read and write files in the server's file system, using the permissions of the database's owning user. Therefore, their use is restricted to superusers. (In contrast, the client-side import and export functions read and write files in the client's file system, using the permissions of the client program. Their use is not restricted.)

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