Week 4 Reading notes

Database from Wikipedia

"A computer database is a structured collection of records or data that is stored in a computer system"
The software to organize a database is a database management system. (DBMS)
The 90s brought along object oriented databases.
The 2000s brought along XML databases.

Types of database organization:
-Hierarchical-data is organized in an inverted tree structure
-Network-records can be a part of any number of named relationships

A relational database used the relations from a field of set theory notion.
SQL-special database language that users use to ask the database a "question".
A Network model database allows a record to be accessed w/o the one above it being accessed.

Database transactions use the ACID rule
-A=Atomicity-transactions must all be done or none of them be done
-C=Consistency-integrity constraints must be preserved
-I=Isolation-two transactions cannot interfere with one another
-D=Durability-transactions cannot be aborted

Three types of replication
-Master/Slave all requests are first performed by the master then copied by the slave
-Quorum-majority rules!
-Multimaster-syncs via transaction identifier

Security enforcement
-Access control
-auditing
-encryption

Setting the Stage by Anne J Gilliland

Metadata is "data about data".
Content, context and structure are reflected through metadata.

"Library metadata includes indexes, abstracts, and catalog records created according to cataloging rules and structural and content standards such as MARC, LCSH, and AAT.

Types of Metadata-
administrative
descriptive
preservation
technical
use

Attributes and characteristics of metadata
Source of metadata
method of creation
nature of metadata
status
structure
semantics
level

Lifecycle of digital data
-Creation and multiversioning
-Organization-categorizing once an object is digitized
-Searching and retrieval-metadata created for users to search and retrieve the object via computer
-Utilization-object being used in the digital format
-Preservation and disposition-making sure the metadata are usable(upkeep)


An Overview of the Dublin Core Data Model--Eric Miller
"The Dublin Core Metadata Initiative is a international effort designed to foster consensus across disciplines for the discovery-oriented description of diverse resources in an electronic environment"

DCMI focuses on Semantic Clarification and identification of common cross-domain qualifiers.

Basis for DCMI requirements:
-Internationalization
-Modularization/Extensibility
-Element Identity
-Semantic Refinement
-Identification of encoding schemes
-Specification of controlled vocabulary
-Identification of structured compound values