My PostgreSql installation directory is: G:\Apps\PostgreSQL
Database files are stored in: G:\Apps\PostgreSQL\14\data\base
Execute sql to view database information:
select oid, datname from pg_database ; --pg_database table stores information about available databases
The result is as follows: oid corresponds to the folder name in the base directory
Execute SQL to view data table information:
select relname, relower, relfilenode from pg_class; --pg_class table record table and almost everything that has fields or those similar to tables
The result is as follows: where relfilenode corresponds to the file name under G:\Apps\PostgreSQL\14\data\base
Postgresql system table description can refer to: system table (postgres.cn)