While the physical databases are capable of storing millions of records, the practical maximum number of records that can be entered in the various database tables depends much on the type of database, the number of simultaneous users, and the physical server hardware.
Experience has shown that Microsoft Access databases with 5 to 10 users experience a gradual slowdown as more records are added with the practical limit being in the range of 50,000 to 100,000 records per table. Microsoft Access databases also have a physical file size limit of 2 Gigabytes.
SQL databases are much more robust and still perform responsively with millions of records.