Bluffers guide to data

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Bluffers guide to data

• Patricia Sleeman
• Assistant archivist, UKNDAD

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• Brief and hopefully uncomplicated overview of
  data and databases from an archivists
  perspective.

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• What
• Issues and problems

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So what is data?

• Data consists of basic units of information, in a
  document many items of data are assembled to
  present an argument or describe an activity.
  Until recently most data were preserved and
  transmitted on paper (or, in more ancient times,
  on other media such as stone). I like this image
  taken from the National Archives of Australias
  site on e-permanence

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• Sometimes we find data in the form of lists, as
  in a telephone directory, where the aim is not to
  present an argument but to provide the raw
  material for a future action (e.g finding
  someones phone number).
• In this case it is crucial that the data be
  classified in such a way as to make searching
  easy. In this instance it is crucial that the
  data be classified in such a way as to make
  searching easy (the names are listed in
  alphabetical order for each town or area)

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• As we well know, to-day data is stored
  increasingly in electronic format.
• A collection of electronic records is termed a
  file, in paper record keeping practice a file is
  a group of records which are accumulated in the
  conduct of business within a paper cover (which
  may be composed of several parts).
• Electronic files may be thought of as similarly
  constructed, however, records within electronic
  files do not necessarily need to be physically
  collected together as long as they are all
  identified as belonging to the same file and as
  long as they are able to be displayed as
  belonging to the same file.

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• Computer files are customarily categorized as
  text, data, or image files. Text files, which may
  be produced by word processing programs and other
  software, contain character-coded letters,
  numeric digits, puntuation marks and other
  symbols encountered in typewritten documents.
• Data files contain records that are subdivided
  into one or more data elements called fields
  which store particular categories of information.
  

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• So to be able to find a specific item of
  information, it has to be structured, there are
  two ways of structuring data depending on the
  information's purpose
• Documents this structure is used when data are
  arranged in an ordered fashion to present an
  argument or describe an activity.
• Databases data are placed in a 'pool' of
  information from which they can be retrieved

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NDAD

• NDAD preserves and provide access to databases.
  Again these can be thought of in the most general
  terms as information which can be represented as
  a set of tables of information, in which columns
  contain a particular data item, and rows identify
  subjects for which data items are recorded much
  like, very much like a register.

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Databases

• Although the elements in these tables are
  typically numbers or simple text, they may be
  pictures or even more complex multimedia items
  such as sound, documents, video or GIS??.
• Basically The key attribute which causes a
  particular set of computer records to be selected
  for preservation in NDAD rather than in the PRO's
  related EROS project is this tabular nature of
  the data, and its ability to be processed or
  analysed in some way by the computer system.

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Relational database

• A database consisting of multiple tables (rows
  representing records and columns representing
  attributes) whose relationship is explicit. For
  example, a personnel database might consist of
  separate tables for employees, salary,
  department, and family data with the employee
  number ( a unique identifier) being the link
  between the various tables. (Dollar)

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Metadata,

• So, EROS, deals with what are essentially digital
  forms of traditional paper documents but NDAD
  handles this kind of structured data? Not so
  simple, as NDAD does actually contain some
  digital documents, and digital forms of paper
  documents. These are documents which are
  strongly associated with the datasets and are key
  to their full understanding, and they form part
  of the archive with the datasets proper. Such
  documents include

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Data dictionary

• At the beginning of this presentation I said that
  data is the same as information, well Im going
  to contradict myself as data on its own is not
  information as it depends on a data dictionary to
  make this statement true.
• It is integral to our understanding of data held
  within a database holding information about the
  definition, structure and usage of data that may
  include the name of each data element, its
  definition (size and type), where and how it is
  used, and its relationship to other data.

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So whats a dataset?

• A computer file or related set of computer
  files, forming part of NDAD, which is organised
  under a single descriptive title and is capable
  of being described as a unit in the finding aids
  . It may comprise one or more accessions. (NDAD
  glossary)

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Types of datasets

• 'Dynamic where a database that is 'open' within
  its active life and where the data is
  overwritten, this data could be archived at
  regular intervals
• Closed/static where data is continually added to
  the database and data is not overwritten again
  this data could have been archived at regular
  intervals

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Permanent preservation

• At NDAD data is stored as a flat file. This a
  file of records whose organisation is rectangular
  and does not support hierarchical relations. A
  record consists of a series of attributes called
  data elements. The relationship among and between
  data elements is implicit.

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We are now in the era of multi-dimensional data
created by GIS, object oriented databases,
hypermedia and multimedia even virtual reality
research environment, that cannot be retained in
software-independent (or flat) formats and with
which archivists need to be involved from the
moment of creation if they are going to have a
hope of managing them. (A Gilliland-Swetland-
'For the record')