Temporary file created by SQLite, a compact database program often embedded into mobile and desktop applications; used by the database for shared memory storage and is automatically created and maintained by SQLite; not meant to be opened manually.
DB-SHM files are also created with .DB-WAL files. Both files are created as extra temporary files for a database and do not need to be copied with the original database to preserve the data. Since SQLite is a popular technology, you may see these files in an application data directory.
NOTE: A database file mydb.db may have mydb.db-shm and mydb.db-wal temporary files.