Database System Concepts and Architecture

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Chapter 2

• Database System Concepts and Architecture

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Evolution of computing

• Database has evolved since nearly every stage of
  computing, from
• mainframes, which are monolithic
• Client-server
• Web-based

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Data Models

• A collection of concepts used to describe the
  structure of a database
• Data types
• Relationships
• Constraints
• Etc

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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 lets see

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Representational data model

• Relational data model (our main discussion in
  this class)
• Network data model (uses directed graphs)
• Hierarchial data model (history)
• Object data model (this is new!)

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Database schemas

• Schemas description of the database, but not the
  database itself!
• Example of a schema diagram

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• Not included in the schema diagram above
• Data types?
• Relationships?
• Constraints, such as students in CS major must
  take CS1310

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Database states

• Also called snapshot
• After we define, generaly 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

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Three Schema Architecture

• Internal schema describes the physical storage
  structure of the database
• Conceptual schema structure of the whole
  database for a community of users
• External schemas for user views

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Data Independence

• Logical data independence we can change the
  conceptual schema without changing the
  application program
• 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.

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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

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DBMS Interfaces

• Menu based interface
• Forms based interface
• Graphical user interface
• Natural language interface, you can ask, Show me
  all the students with GPA gt 3
• Parametric interface, such as xBase

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Database utilities

• Loading utility, or importer
• Backup utility, usually to tape
• File optimizer or reorganizer
• Performance monitoring fragmentation, load
  balancing, etc.

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Classification of DBMS

• Single user vs multi user
• Centralized vs distributed
• Price!
• OLTP support?
• OLAP support (read page 842)

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Group Assignment

• Comparative Study of Popular DBMS

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Which ones?

• Group 1 (Haswar, Conna, Vicky)
• MySQL
• MS-SQL Server
• FoxPro
• Group 2 (Fitri, al-Harith, Avi)
• MySQL
• MS-SQL Server
• IBM DB2

• Group 3 (Danu, Lia, Narpati)
• Oracle database
• Postgres
• Borland Interbase
• Group 4 (Armand, Tia, Aryo)
• FoxPro
• MS-Access
• Informix

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What to look for

• Use theories in chapter 1 2!

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Deliverables

• Presentatoin (of course)
• Due next week
• Paper, submitted to the TAs Elan and Amir
  (again!)