meljun database dbms lecture

8/14/2019 MELJUN Database Dbms Lecture

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DATABASESYSTEMMELJUN CORTES


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We Are Learning TodayTo recognize what a database is and identifywhere one might be used in and out of school.

To reconize the meaning ofkey database termssuch as Table, Record, Field, Form, Report andQuery.To understand what querying a database is.Understanding Basic Database concepts

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DATA ORGANIZATIONCHARACTER is the basic building block of DATA which

consist of upper & lower case letter numeric

digit (0, 1, 2, etc.) or special character (-, +, -).

CHARACTER are put together to form a FACT.FACT are called Field, Item, Word, or String of Character.FACT a number, a name, or a combination of Character.

RECORDa collection of related FACTS.Example:1.) Employee Recordit is collection of FACT about one employee.

2.) It indicates name, address, phone #, pay rate, earning made to

date & so on.

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FILE

is a collection of related RECORD.Example:1.) A collection of all employee record for one company

would be an Employee File.

2.) Inventory Filecollection of all inventory record for

a particular company or organization.

DATA ORGANIZATION

Student ID# : 034456

Student Name : MELJUN CORTESCourse : BSCS 4

Birthday : October 2, 1975

Zodiac Sign : Libra

Student ID# : 034456Student Name : MELJUN CORTES

Course : BSCS 4


Zodiac Sign : Libra

Student ID# : 034456Student Name : MELJUN CORTES

Course : BSCS 4


Zodiac Sign : Libra

FILERECORD

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DATA ORGANIZATIONHIERARCHY OF DATA :

CHARACTER are combined to make a Fact.FACT are combined to make Record.RECORD are combined to make File.FILE are combined to make DataBase

DataBase

File

Record

Fact

Character

Note: The Heart of most Organization isDATA.DataBase is a collection of integrated & related master file.Note: A data base is used as the raw material or input data

for all of the application system perform by the

organization. MELJUN CORTES


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ATABASE SYSTEM

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Number Date Customer Amount

101 Oct 30, 2009 MELJUN CORTES 12,500

102 Dec. 12, 2009 PIOLO PASCAUL 78,452

103 Nov. 15,2009 MARTIN RIVERA 89,500

104 Jan. 14,2010 SAM MELBY 10,500

Each ROW is a RECORD.Each COLUMN is a FIELD.COLUMN TITLES are FIELD NAME.The type of DATA stored in a FIELD is a FIELD TYPE.The number of CHARACTER in a FIELD is its FIELD WIDTH.A DATABASE is composed of one or more TABLE.A DATABASE is a FILE which is created in automated DBMS SOFTWARE.

FIELD NAME

RECORDRECORDRECORDRECORD

TABLE


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EXAMPLE OF DATABASE STRUCTURE:Structure for Database :C:\STLMASTER.dbfNumber of Data Records : 268 recordsDate of last update : 10/26/1996Filename of DATABASE FILE : STLMASTER.dbfField Field Name Field Data Types Field Width Dec Index

1 AppNumber character 62 AppDate date 83 Name character 204 Address character 305 LoanAmount numeric 12 26 Rebate numeric 7 27 Interest numeric 7 28 Balance numeric 12 29 Penalty numeric 7 2


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DATA ORGANIZATIONDATA is a raw materials or input to anydata processing system.- is considered as INPUT DATA.- is manipulated to provide OUTPUT DATA.Example: Student Admission Form & Enrollment Form

Pay Slip of an employee

INFORMATION when this OUTPUT DATA can be

used to help people make economic

decision making.

DATA PROCESSING is that procedures of transforming

INPUT DATA into

desired OUTPUT DATA.MELJUN CORTES


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DATA ORGANIZATIONINFORMATION PROCESSING a special case ofdataprocessing is the

procedure of transforming data intoinformation whichcan be used to make better decision.

Data Processing System includes all people, procedures &

computer device used to produce

desirable output or meaningful

information.

Information Processing System includes all people,procedures, computerdevices used to procedure usefulthat can be used in decision makingMELJUN CORTES


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DATA ORGANIZATIONOverview of DATA Processing

Ex. Payroll System

INPUT PROCESSING OUTPUT

Example:1.) Pay Rate2.) Hours Worked3.) PayrollDeduction

Example:

1.) Classifying

2.) Sorting

3.) Calculating

4.) Storing

5.) Summarizing

6.) Reproducing

Example:1.) Pay Slip2.) PayrollReport

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DATABASE SYSTEMDatabase ConceptsData vs.Information

DBMSMELJUN CORTES


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DatabaseComputerized RecordKeeping SystemCollection of Data used by anorganization to

1. Record its Operations2. Support Decision Making

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DataRaw facts and figuresCan be of typeTextNumber

Sound, Image, Chart,VideoMELJUN CORTES


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InformationProcessed Data

Used for Decision Making

Data is alsoINFORMATION

Information createsDATA

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ATABASE SYSTEM

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104 Jan. 14,2010 SAM MELBY 10,500


FIELD NAME


TABLE


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A DataBase Management System

(DBMS)often just called Database SoftwarInput Processing Output

Storing

Querying

Sorting

FORMS REPORTSSourcesDocumentsLike:Enrollment Forms

PrintedDocumentsLike:Assessment Forms

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Database TerminologyTerm MeaningDatabase

Table

Record

Field

Data Type

An organised collection (or Store) of data.A collection of related records, such

as all the pupil records in a class.

A collection of related fields, suchas a pupils record.An individual data item, such asFirstname or Date of Birth.Type of information in a field such astext, numeric, date and boolean (Yes/No)

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The Russian Doll Analogy

Fields insideof

A Database

Tablesinside ofRecordsinside of

Data insideof

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DATABASE SYSTEM


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ATABASE SYSTEM

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104 Jan. 14,2010 SAM MELBY 10,500


FIELD NAME


TABLE


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What is a DBMS?A collection of computer programs that allowstorage, modification, and extraction ofinformation from a database. There are manydifferent types of DBMS ranging from small

systems that run on personal computers tohuge systems that run on mainframes.

Examples--

Computerized library systems, automated

teller machines, flight reservation systems,

computerized parts inventory systems.

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DATABASE SYSTEM


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IntroductionTo DBMSConcepts

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DATABASE SYSTEM


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What is a DBMS?A collection of computer programs that allowstorage, modification, and extraction ofinformation from a database. There are manydifferent types of DBMS ranging from small

systems that run on personal computers tohuge systems that run on mainframes.

Examples--

Computerized library systems, automated

teller machines, flight reservation systems,

computerized parts inventory systems.

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DATABASE SYSTEM


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Examples of DATABASE(1)Admission SystemExamination SystemLibrary SystemPayroll & PersonnelManagement SystemAccounting SystemHotel Reservation SystemAirline Reservation System

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DATABASE SYSTEM


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Examples of DATABASE(2)Patient Recording SystemInventory SystemSales and Purchase and AccountingSystemEnrollment SystemKnowledge-Based Management SystemEvery Government, Military, Private andother organizations plus Individual canmake use of DB

DATABASE SYSTEM

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Data ManagementManual Filing SystemComputerized Filing SystemDatabase Systems

DATABASE SYSTEM

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Filing SystemEvery Department/Company has its ownData File(s)

Application to Maintain Data File(s)-- Computerized Data Maintenance System

DATABASE SYSTEM

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Library System - ExampleMembers

Catalog

Register

Members

Management

Application

Catalog

Management

Application

Transaction

Management

Application

Lists of All Members,

New Members,

Joins between

specified Dates. etc

Lists of All Books,

New Books,

Issued Books,

Lost Books,. etc

Books Issued Today,

Books Receipt Today,

etc

Files Applications Operations

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Database SystemSingle, Central, Large Repository

Shared ResourceHave Logical Connectionsamong data itemsDBA is responsible of its design,creation and maintenance

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Is a PERSON


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Members

Management

Application

Catalog

Management

Application

Transaction

Management

Application

Lists of All Members,

New Members,

Joins between

specified Dates. etc

Lists of All Books,

New Books,

Issued Books,

Lost Books,. etc

Books Issued Today,

Books Receipt Today,

etc

Members

Catalog

Register

DBMS

DATABASE SYSTEM

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Library System - Example


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DBMSSoftware Package that providesSupport to applications system-- Computerized DATA HandlingUser-interface for on-line queries

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Advantages of DBMS (1)Sharing of DataControl of Redundancy-(unnecessary wastage of disk space)

Data ConsistencyImprovement of Data StandardsImprovement of Data Integrity-(Intra-record, inter-record, referential)Balancing of Conflicts

Faster Development of New Applications

DATABASE SYSTEM

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Advantages of DBMS (2)Better Security

PasswordsEncryptionViews and Stored Procedures

Better Data Accessibility(query language- SQL programming)

Economy of ScaleTransaction handlingBetter backup and Recovery Procedures

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Disadvantages of DBMSHigher Costs of

DBMSHardwareConversionProgramming

Slow Processing of SomeApplicationsMore Security RisksMore Difficult Recovery

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Kinds of DatabasesRelational: Oracle 9i/8i, SQL-Server 2000/7.0/6.5,

Teradata, Sybase(SQL Anywhere),

DB2, Informix

MS-Access, Foxpro 2.6/2.5,dbase IV/3 +

Network e.g. IDS Server

Paradox, FoxBase, Dbase3+, DbaseIV

DBU, Visual FoxPro, MS-Access Windows 7

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Relational DBMS

TABLE

TABLE

TABLETABLE


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Important RDBMS ObjectsTablesViewsTriggersStored ProceduresFunctionsPrimary KeyForeign Key

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Networked DBMS

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SQL:


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SQL:

It is an acronym for Structured QueryLanguage.It is the language in which, the clientsends the requestto the database for dataEg. Select name, address

From empWhere city = BUTUAN CITY

SQL:

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PL/SQL:It is an acronym for Programming Language/Structured QueryLanguage

Apart from writing the SQL you also have the programminglanguage constructs like

If then else (checking conditions)

Looping (Executing the set of statements more that once) Exception and error handling (Taking care of run time errors)

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Database DesignDatabase design

is the process of producing a detailed

data model of a database. This logical data model contains all theneeded logical and physical design choices and physical storageparameters needed to generate a design in a Data DefinitionLanguage, which can then be used to create a database. A fullyattributed data model contains detailed attributes for each entity.

Process: Determine the data to be stored in the database Determine the relationships between the different data elements Superimpose a logical structure upon the data on the basis of

these relationships.

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Database ObjectsA Database Trigger is procedural code that is automatically executed in

response to certain events on a particular table in a database. Triggerscan restrict access to specific data, perform logging, or audit datamodifications.A Database View is a virtual or logical table composed of the result setof a query. Unlike ordinary tables (base tables) in a relational database,a view is not part of the physical schema: it is a dynamic, virtual tablecomputed or collated from data in the database. Changing the data in atable alters the data shown in the viewIn relational databases, SQL databases, and flat file databases,a Table is a set of data elements (values)that is organized using a model of horizontalrows and vertical columns.

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In database packages, the term Cursor refers to a control structureor the successive traversal (and potential processing) of records in aresult set.Transaction Log (also database log or binary log) is a history ofactions executed by a database management system to guaranteeCID properties over crashes or hardware failures. Physically, a log is

a file of updates done to the database, stored in stable storage.Database Index is a data structure that improves the speed ofoperations in a table. Indexes can be created using one or morecolumns, providing the basis for both rapid random lookups andefficient ordering of

access to records.Stored Procedure is a subroutine available to applicationsaccessing a relational database system. Stored procedures(sometimes called a sproc or SP) are actually stored in thedatabase.

Database Objects

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NormalizationWhy Normalize?

Ideally, a relational database table should be designed in such away as to exclude the possibility of update, insertion, and deletionanomalies. The normal forms of relational database theory provideguidelines for deciding whether a particular design will be

vulnerable to such anomalies. It is possible to correct anunnormalized design so as to make it adhere to the demands ofhe normal forms: this is called normalization.

A

tablethat is not sufficiently normalized can suffer from

logical inconsistencies of various types, and fromanomalies involving data operations causingUpdate, Insert and Delete Anomalies.

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TRANSACTION MANAGEMENTWhat is a Database Transaction ?

A database transaction is a unit of interaction with adatabase management system or similar system that istreated in a coherent and reliable way independent of othertransactions. In general, a database transaction must be

atomic, meaning that it must be either entirely completedor aborted. Ideally, a database system will guarantee theproperties of Atomicity, Consistency, Isolation andDurability (ACID) for each transaction.

A Simple Transaction1. Begin the transaction2. Execute several queries3. Commit the transaction

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ACIDIncomputer science, ACID (Atomicity, Consistency, Isolation, Durability)is a set of properties that guarantee that database transactions are processed reliably. In thecontext of databases, a single logical operation on the data is called a transaction.

Atomicity - Atomicity refers to the ability of the DBMS to guarantee that either all of the tasksof a transaction are performed or none of them are.Consistency - Consistency refers to the database being in a legal state when the transactionbegins and when it ends. This means that a transaction cannot break the rules, or integrityconstraints, of the database.Isolation - Isolation refers to the ability of the application to

make operations in a transaction appear isolated fromall other operationsDurability -Durability ensures that the results of a completedtransaction are permanent and can survive future system andmedia failures; that is, once they are done, they can not be undone.

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Kinds of DatabaseConsultants

DATABASE Designers

is a personDATABASE Developers

is a person

DBA (Data Base Administrator)

is a person

DATABASE SYSTEM

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DATABASE Designers:These consultants Analyze,design the complete structureof the database.They design Tables, Views,Normalization, ER Diagram,Integrity constraints, etc.

DATABASE SYSTEM

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DATABASE Developers:These consultant write storedprocedures, triggers, functions, etc.Technical terms found in the resumesuch consultants TriggersStored ProceduresPackagesUnix Shell Scripting

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DBADMINISTRATOR:These consultants profileincludes installation,configuration, migration,backup, recovery operationsVarious Tasks of the DBA are:

a) Granting accessb) User creation and deletionc) Performance tuningd) Query optimization

DATABASE SYSTEM

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Related Skills in DATABASESYSTEMata WarehousingDevelopment of a data warehouse includes developmentof systems to extract data from operating systems plusinstallation of a warehouse database system thatprovides managers flexible access to the dataData MiningA class of database applications that look for hiddenpatterns in a group of data that can be used to predictfuture behaviorData ModelingThe analysis of data objects and their relationships toother data objects. Data modeling is often the first stepin database design and object-oriented programming asthe designers first create a conceptual model of howdata items relate to each other. Data modeling involvesa progression from conceptual model to logical model tophysical schema.

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