Chemical Structures in Databases (blog article 1 of 8) : Cope-Chat cards, some 1930's technology

A most fascinating and simple early technology for the indexing of information, a precursor to databases and their respective indexes, used Cope-Chat (Copeland and Chatterson Ltd) index cards. These stiff cards were used for a plethora of indexing purposes with applications that included patient hospital records, patent searching, library indexes, and in the manipulation of census data. The cards were also used by scientists as a mechanism to index personal research interests until only a few decades ago; recall that up until the mid 1980’s, personal computers or computerised database systems were neither available nor accessible. 

Although Cope-Chat cards varied in size, most were approximately 9″ wide by 4″ in height, often ruled, and importantly featured a number reproducibly spaced numbered or labelled punched holes around all four of the edges. For chemical research purposes, a classification or category was assigned to each hole in the card index (eg. reaction type: metallation, substitution, oxidation; reactant or product functional group or moiety: ester, azide, reaction scheme contains substituted imidazole, reaction scheme contains substituted pyrrole). Pertinent notes were hand written on the card and often included a reaction scheme and citation to the original literature source. Prior to filing the index card in the card index, any relevant edge holes that represented a predefined category would be cut out opening the hole to the edge. The Cope-Chat index card containing the citation and other notes were then filed in a random position in the card index.

To search the card index the researcher would insert a thin piece of wooden dowel or knitting needle through the numbered or labelled hole in the card index (recall the hole represents a predefined research category, topic, author etc). While leaving the knitting needle through these holes in the card index, the cards would then be lifted out of their container. The index cards that remained behind, those that have the hole cut out and open to the card edge, would match the search criteria. Boolean searches could also be performed. For example to search on two predefined categories in an AND, OR, or NOT fashion, two knitting needles would be used.

Such an approach is used today in modern RDBMS (Relational Database Management Systems) systems such as: IBM DB2, Oracle, Microsoft SQL Server, and PostgreSQL etc. In a very simplistic system, each Cope-Chat card is represented by a single row in a database table. Each of the holes punched around the edges of the card is represented by a table column header. The result set obtained from querying a database table is analogous to inserting the knitting needle into the card index and retrieving the cards that remain/fall through.

In summary:

  • Cope-Chat cards are ingenious, simple, and far from new
  • Cope-Chat cards were being used to index chemical and other information sources from the mid 30’s
  • Cope-Chat cards lend them self neatly to leading edge RDBMS commercial products such as Oracle and IBM DB2
  • Cope-Chat cards are a thing of the past. Nowadays we use computers and databases for the retention and retrieval of structured and unstructured information.

This is the first of eight blog articles with a subtitle of “Chemical Structures In Databases”. The next article in the series can be found here.

— Published by Mike, 12:20:04 06 April 2018 (BST)

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