Database system concepts and architecture s
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Database System Concepts and Architecture s. Indra Budi [email protected] Which of the following is a problem of lists that is solved by using a database?. data inconsistencies problems adding data problems deleting data missing data All of the above.

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Database system concepts and architecture s

Database System Concepts and Architectures

Indra Budi

[email protected]


Which of the following is a problem of lists that is solved by using a database

Which of the following is a problem of lists that is solved by using a database?

  • data inconsistencies

  • problems adding data

  • problems deleting data

  • missing data

  • All of the above


Database system concepts and architecture s

  • In database processing systems, the data is directly accessed only by the….

  • In database application processing systems, the user interacts directly with the…


Evolution of computing

Evolution of computing

  • Database has evolved since nearly every stage of computing, from:

    • mainframes, which are monolithic

    • Client-server

    • Web-based


Data models

Data Models

  • A collection of concepts used to describe the structure of a database

    • Data types

    • Relationships

    • Constraints

    • Etc


Categories of data models

Categories of Data Models

  • Conceptual data models: high level

  • Physical data models: how data is actually stored in a disk

  • Representational data models: somewhere between those two… let’s see…


Representational data model

Representational data model

  • Relational data model (our main discussion in this class)

  • Network data model (uses directed graphs)

  • Hierarchical data model (history…)

  • Object data model (this is new!)


Database schemas

Database schemas

  • Schemas: description of the database, but not the database itself!

  • Example of a schema diagram:


Database system concepts and architecture s

  • Not included in the schema diagram above:

    • Data types?

    • Relationships?

    • Constraints, such as “students in CS major must take CS1310…”


Database states

Database states

  • Also called ‘snapshot’

  • After we define, generally a database is at the ‘empty state’

  • We get the ‘initial state’ after we first load the database

  • Valid state is a state which satisfies the structure and constraints in the schema


Three schema model

Three Schema Model

  • ANSI/SPARC introduced the three schema model in 1975

  • It provides a framework describing the role and purpose of data modeling


Three schema model cont

Three Schema Model (cont.)

  • External schema or user view

    • Representation of how users view the database

  • Conceptual schema

    • A logical view of the database containing a description of all the data and relationships

    • Independent of any particular means of storing the data

    • One conceptual schema usually contains many different external schemas

  • Internal schema

    • A representation of a conceptual schema as physically stored on a particular product

    • A conceptual schema can be represented by many different internal schemas


Data independence

Data Independence

  • Application insulated from how data is structured or stored

  • Logical data independence: we can change the conceptual schema without changing the application program (internal schema)

  • Physical data independence: we can change the internal schema without changing the conceptual schema. It might be because file database must be reorganized for fine tuning.


Database languages

Database Languages

  • Data definition language

  • View definition language

  • Data manipulation language

    • High level: SQL, set-at-a-time processing

    • Low level: VB, COBOL, record-at-a-time processing


Dbms interfaces

DBMS Interfaces

  • Menu based interface

  • Forms based interface

  • Graphical user interface  utilize menu & forms

  • Natural language interface, you can ask, “Show me all the students with GPA > 3”

  • Parametric interface, such as application for Bank Teller

  • Interface to DBA: create account, granting account, changing schema, delete db, etc.


Dbms utilities

DBMS utilities

  • Concurrency Control

  • Loading utility, or importer

  • Backup utility, usually to tape

  • File optimizer or reorganizer

  • Performance monitoring: fragmentation, load balancing

  • Commit & Rollback

  • etc


Transaction an execution of a db program

Transaction: An Execution of a DB Program

  • Key concept is transaction , which is an atomic (all-or-nothing property), sequence of database actions (reads/writes).

  • Each transaction, executed completely, mustleave the DB in a consistent state, if DB isconsistent when the transaction begins.

    • Users can specify some simple integrity constraints on the data, and the DBMS will enforce these constraints.

    • Beyond this, the DBMS does not really understand thesemantics of the data. (e.g., it does not understandhow the interest on a bank account is computed).

    • Thus, ensuring that a transaction (run alone) preservesconsistency is ultimately the user’s responsibility!


Classification of dbms

Classification of DBMS

  • Data model: relational, network, hierarchical, etc.

  • Number of users: Single user vs multi user

  • Centralized vs distributed

  • Price…!

  • OLTP support?

  • OLAP support (read page 842 of Elmasri)


Database system concepts and architecture s

Which of the following plays an important roles representing information about a real world in the database ?

  • The data definition language

  • The data manipulation language

  • The buffer manager

  • The data model


What is the differences

What is the differences ?

  • Database Schema Vs Database State ?


Group assignment

Group Assignment

Comparative Study of Popular DBMS


Which ones

Group 1 (Mahesa, Evan Bambang, Panca)

MySQL

MS-SQL Server

FoxPro

Group 2 (Lamo, Siti, Arief)

Informix

MS-Access

IBM DB2

Group 3 (Tyas, Dika, Ririn)

Oracle database

Postgres

Borland Interbase

Which ones?


What to look for

What to look for ?

  • Use theories in Elmasri Ch 1 & 2, and Kroenke Ch 1!

  • Examples: function, concurrency control, type, price, primary use ?, performance, capacity, etc.


Deliverables

Deliverables

  • Paper, submitted to me, you can give me directly or email me at [email protected], due date on Tuesday, September 14th 2004

  • Presentation (of course)  Wednesday, September 15th 2004


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