Adv Databases Flashcards
What is XML used for?
Data communication, data sharing, patching and for separating HTML
What is a Namespace?
XML namespaces are used for providing uniquely named elements and attributes in an XML document
Namespace - how would you differentiate a element?
and
What is the DOM
Programming standard for manipulating XML documents (Dom plays with Doc)
Define XML Schema
A document defining elements to ensure a set of rules are implemented to the XML. An example is an Occurrence Indicator to declare the maximum number of elements
Name the three group of Indicators
Order, occurrence and group
What is XPATH?
A way of referring to the contents of an XML document
What is RDF?
Resource Description Framework is a method of describing resources that can be easily read by computers
What is the difference between a well formed XML document and a valid XML document?
Valid is readable by humans and well formed is readable by computers
What is SPARQL
Current querying language for RDF
What is URI?
Web scope identifier that can be used to identify any resource
What is a literal?
Set of lexical values
What is a blank node?
Locally scoped identifier for resources that are not otherwise named
What does a triple consist of?
Subject, predicate, object
What is a prefix?
An abbreviation of a URI
Define OWA?
Open world assumption assumes that data is incomplete
What two standards were introduced to add additional, well-defined vocab for RDF?
RDF schema and Web Ontology Language
What does an RDF class allow for?
Simultaneous typing of resources. A RDF class is an ER entity
What is taxonomy?
A classification schema for a vocabulary
Why are there distributed databases?
For data protection laws, redundancy, performance, merging organizations.
What is replication in distributed databases?
Where the DB stores some data at every node.
What is synchronized replication in distributed databases?
Every node is kept up to date after every transaction
What is asynchronized replication in distributed databases?
Every transaction is held in a queue
What is key for performance management?
Good design, efficient connection management and properly formed SQL
What is the three tier architecture?
Client –> Application Server –> Database
What is connection pooling and name one benefit.
Recycling connections which can save time when querying in the future.
Why is a cursor bad?
Takes up memory and locking
What is Autotrace?
Debugging mechanism that gives an execution part of optimizer and statement execution stats
What is metadata?
Data which is about data!
What are the two types of metadata?
Structural (how the data is stored) and Descriptive (information about the data itself)
True or false - Everyone should be able to see metadata
FALSE! Metadata should be kept a secret
What is a distributed database?
DB with more than one DBMS
