/var/lib/rpm

/var/lib/rpm stores the RPM database (in either SQLite or Berkley DB format)?

A corrupted database can be rebuilt with

rpm --rebuilddb

(SQLite) Schema

The rpm database schema has a «master» table:

CREATE TABLE IF NOT EXISTS 'Packages' (hnum INTEGER PRIMARY KEY AUTOINCREMENT, blob BLOB NOT NULL);

Then, there are quite a number of child tables with a foreign key referencing Packages:

Name
Basenames
Group
Requirename
Providename
Conflictname
Obsoletename
Triggername
Dirnames
Installtid
Sigmd5
Sha1header
Filetriggername
Transfiletriggername
Recommendname
Suggestname
Supplementname
Enhancename

All tables have the same definition:

CREATE TABLE IF NOT EXISTS <tabname> (key 'TEXT' NOT NULL, hnum INTEGER NOT NULL, idx INTEGER NOT NULL, FOREIGN KEY (hnum) REFERENCES 'Packages'(hnum));

The two table Installtid and Sigmd5 differ in that the datatype of key is not TEXT but BLOB.