Intro to Databases Flashcards
What does DBMS stand for?
Database Management Systems
What is DBMS?
general purpose software system that facilitates the process of defining, constructing, manipulating and sharing databases among users and applications
also protects and maintains the database
defining
specifying data types, structures and constraints of data
metadata
descriptive information about a database
Phases of design
- Requirements specification and analysis
- Conceptual design
- Logical design
- Physical design
Main characteristic of database approach
- Self-describing nature
- Insulation between data and programs
- Support of multiple views
- Sharing of data and multiple transaction processing
Self describing
Data items and data values stored together in one structure
Program-data independence
Structure of data files is stored separately from access programs
OLTP
online transaction processing
single access to a resource (i.e. airline agents trying to book a seat on a flight)
Isolation property
each transaction appears to be executed by itself
Atomicity property
All database operations are executed or none are
Database Administrator
authorizes access to database, monitoring use and acquiring more resources or software as needed
Database Designers
identifies data to be stored, chooses the proper structure to store them in, and designs views
Impedance mismatch problem
database data structure incompatible with programming language’s data structure
Database system
DBMS + database
