FDS Chapter 1 - MT Part 2

data files

store the database itself

data dictionary

stores metadata about the structure of the database, in particular the schema of the database

indices

can provide fast access to data items.

a database index provides pointers to those data items that hold a particular value

DDL interpreter

interprets DDL statements and records the definitions in the data dictionary

DML compiler

translates DML statements in a query language into an evaluation plan consisting of low-level instructions that the query evaluation engine understands

• it performs query optimization; that is, it picks the lowest cost evaluation plan from among the various alternatives

Query evaluation engine

executes low-level instructions generated by the DML compiler

transaction

a collection of operations that performs a single logical function in a database application (atomicity, consistency. durability)

transaction-management component

ensures that the database remains in a consistent (correct) state despite system failures (e.g., power failures and operating system crashes) and transaction failures

concurrency-control manager

controls the interaction among the concurrent transactions, to ensure the consistency of the database

okey

basa

two-tier architecture

database application:

• the application resides at the client machine, where it invokes database system functionality at the server machine

three-tier architecture

the client machine acts as a front end and does not contain any direct database calls

• the client end communicates with an application server, usually through a forms interface

• the application server in turn communicates with a database system to access data

naive users

Database Users:

• are unsophisticated users who interact with the system by using predefined user interfaces, such as web or mobile applications

application programmers

Database Users:

• are computer professionals who write application programs. they can choose from many tools to develop user interfaces. schema and physical-organization modification

sophisticated users

interact with the system without writing programs. instead, they form their requests either using a database query language or by using tools such as data analysis software. analysts who submit queries to explore data in the database fall in this category

Database Administrator (DBA)

a person who has central control over the system is called?

1950s and early 1960s

Data processing using magnetic tapes for storage

• tapes provided only sequential access

punched cards for input

Hard disks allowed direct access to data

network and hierarchical data models in widespread use

Tedd Codd defines the relational data model

• Would win the ACM Turing Award for this work

• IBM Research begins System R prototype

• Oracle releases first commercial relational database

High-performance (for the era) transaction processing

1980s

Research relational prototypes evolve into commercial systems

• SQL becomes industrial standard

Parallel and distributed database systems

• Wisconsin, IBM, Teradata

Object-Oriented database systems

1990s

Large decision support and data-mining applications

Large multi-terabyte data warehouses

Emergence of Web commerce

2000s

Big data storage systems

• Google BigTable, Yahoo PNuts, Amazon

• “NoSQL” systems

Big data analysis: beyond SQL

• Map reduce and friends

2010s

SQL reloaded

• SQL front end to Map Reduce systems

• Massively parallel database systems

• Multi-core main-memory databases