Technical Details

eNummus is a relational Microsoft SQL Server database designed to 3rd normal form. An entity relationship diagram of this database will shortly be included in this section but basically eNummus recognises three primary layers of data to capture adequately the information of an individual coin: the Coin Type, the Coin Type Variation and the Coin.

Coin Type: This is the broad definition of the coin storing obverse and reverse legends and designs, issuer and denomination.
Coin Type Variation: relates to the layer above and stores the points that differ: the issuing mints and monograms and symbols placed in variety of positions around the coin’s obverse and reverse.
Coin (not yet open in eNummus): this layer relates to the Coin Type variation above and stores the data pertaining to a physical coin itself: its diameter, weight, provenance, image, axis etc.

Thus a coin described as:

Numerian. AD 283-284. Antoninianus (22mm, 3.81 g, 7h). Rome mint, 6th officina. IMP NVMERIANVS AVG, radiate and cuirassed bust right / VNDIQVES VICTORES, Numerian standing left, holding globe and sceptre, two captives at feet; KAS. RIC V 423. VF, green patina, a few cleaning marks.

Would be stored in the eNummus database as:

Coin Type:
Numerian;
Antoninianus;
IMP NVMERIANVS AVG, radiate and cuirassed bust right;
VNDIQVES VICTORES, Numerian standing left, holding globe and sceptre, two captives at feet

Coin Type Variation:
Rome mint;
6th officina;
KAS in exergue;
RIC 423

Coin:
22mm;
3.8g;
7h;
VF;
green patina, a few cleaning marks

The coin type therefore can have numerous variations attached – variations from other mints, with other letters and symbols in the exergue, all sharing the same common data of the coin type. Likewise each variation could have numerous attached coins: coins of the same type and variation, but different weights, diameters, grades etc.

The eNummus database was created to provide a datastore for these coin types. The difference between eNummus and the other numerous online ancient coin databases out there are:

1. eNummus attempts only (at this stage) to capture the coin types, not the individual coins themselves. Data particular to the coin itself (weight, diameter, provenance etc) is not retained in eNummus at the moment.
2. Because of the point above, eNummus is not sourced from a mountain of existing coin data (as opposed to coin type data). Unfortunately this means that data has to be entered more slowly, but also the integrity of the data is increased. When a database is amalgamated from a variety of coin sources two coins (ostensibly the same coin type) are rarely described exactly the same: one described “Helmeted head of Athena facing right” and the other “Head of Athena wearing helmet, right” appear as two different coin types, when actually they are the same type just described differently.
3. Hence eNummus, by using authority records enables a “drill down” effect. You can find a coin type, and then browse the corresponding variations, rather than the clutter effect when searching at a “coin” level.
4. eNummus stores monograms and other symbols in such a way that they can be searched and displayed.

The eNummus website is written in PHP5.