Week 4 Notes

Database
Wikipedia Article:

-Computer Database-“ structured collection of records or data that is stored in a computer system”
-relational model most common today
- Database management system (DBMS) used to organize storage of data
-November 1963 first known use of term data base, became a single word “database” in Europe in the 1970s ( and obviously the trend was adopted)
-Charles Bachman was a pioneer in the field; his aim was to make more effective use of the new direct access storage devices becoming available.
-CODASYL created a network database based upon Bachman’s idea. (hierarchical model)
- The relational model proposed by E.F. Codd in 1970. “He criticized existing models for confusing the abstract description of information structure with descriptions of physical access mechanisms.”
- The first successful database product for microcomputers was dBASE for the CP/M and PC-DOS/MS-DOS operating systems.
-1980s focus on distributed database systems and machines
-1990s shifted toward object-oriented database, currently XML database, which “aim to remove the traditional divide between documents and data, allowing all of an organization's information resources to be held in one place, whether they are highly structured or not.”
-hierarchical model- data is organized into an inverted tree-like structure, implying a multiple downward link in each node to describe the nesting, and a sort field to keep the records in a particular order in each same-level list
-network model- records can participate in any number of named relationships. Each relationship associates a record of one type (called the owner) with multiple records of another type (called the member)
-relational model- structured as a table where information about a particular entity is represented in columns and rows. The columns enumerate the various attributes of an entity while Rows (also called records) represent instances of an entity
- Security is usually enforced through access control, auditing, and encryption.
-Locking: how the database handles multiple concurrent operations
- number of database architectures in use

Introduction to Metadata:

-data about data
-important to understand role of metadata “types of metadata can play in the development of effective, authoritative, interoperable, scaleable, and preservable cultural heritage information and recordkeeping systems”
-The common features in all information objects:
1. Content- relates to what the object contains or is about, and is intrinsic to an information object.
2. Context -indicates the who, what, why, where, how aspects associated with the object's creation and is extrinsic to an information object.
3. Structure- relates to the formal set of associations within or among individual information objects and can be intrinsic or extrinsic.
-“museum registrars, library catalogers, and archival processors are increasingly applying the term metadata to the value-added information that they create to arrange, describe, track and otherwise enhance access to information objects.”
-Library metadata- includes indexes, abstracts, and catalog records created according to cataloging rules and structural and content standards such as MARC
-Archival and manuscript metadata includes accession records, finding aids, and catalog records.
-Structure has always played a vital role in information, even before the computer age
-applied outside the repository, the term metadata acquires an even broader scope, i.e on the internet
-Types of metadata include: administrative, descriptive, preservation, technical, use
-little known facts: Metadata does not have to be digital. Metadata relates to more than the description of an object. Metadata can come from a variety of sources. Metadata continue to accrue during the life of an information object or system. One information object's metadata can simultaneously be another information object's data.

An Overview of the Dublin Core Data Model

-DCMI-international effort designed to foster consensus across disciplines for the discovery-oriented description of diverse resources in an electronic environment
-created to enhance searching of document-like objects on the web
-first workshop in Dublin Ohio, hence the name Dublin core(sadly nothing to do with Ireland)
-issues: "Author/Creator" element does not distinguish between corporate authors and personal authors; does not prescribe a syntax for element values
-Simple Dublin Core comprises fifteen elements; Qualified Dublin Core includes three additional elements (Audience, Provenance and RightsHolder
-abstract model provides a reference model against which particular DC encoding guidelines can be compared, independent of any particular encoding syntax.