Function check_integrity 

pub fn check_integrity(
    catalog: &Catalog,
    tables: &HashMap<String, &Table>,
) -> Result<IntegrityReport>

db.checkIntegrity() — walks every declared relation and reports the records whose reference has no counterpart. A diagnosis, not a gate: nothing here is repaired, removed or written. tables supplies the open handles this call can read; a relation naming a table not in it reads as empty, exactly like the TS reference’s this.#tables.has(name) ? ... : [].