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@ngi3

Zlatna sredina

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  • »@ngi3« je žensko
  • »@ngi3« je autor ove teme

Postovi: 453

Datum registracije: 29.07.2003

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1

Petak, 01. August 2003

baze podataka...

cao raja! ovo malo vise lici na molbu nego li na temu :)
zato molim da mi neko objasni sve sto zna o RDBMS (Relation DataBase Menagement System) i njihovom koriscenju SQL-a
hvala!!!
Naucila sam...
Najlaksi nacin da kao osoba rastem jest da se
okruzim ljudima koji su pametniji od mene

2

Petak, 01. August 2003

hehe

Eto ja bas radim database predmet ovog semestra. Reci mi odgovarali ti na engleskom mogu ti kopirati slajdove koje imam sa predavanja. Toliko mi nece biti tesko da ucinim ako ti odgovara. Pozdrav pa javi ;)
mogu ja da se potpisem i bolje...

@ngi3

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(10)

  • »@ngi3« je žensko
  • »@ngi3« je autor ove teme

Postovi: 453

Datum registracije: 29.07.2003

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3

Ponedjeljak, 04. August 2003

naravno da odgovara, bas bih ti bila zahvalna.
ja sad u 5 semestru trebam raditi na tome pa se malo k'o i pripremam a i na stazu to imam k'o zadatak.
unapred hvala
BIG greeting from Angie
Naucila sam...
Najlaksi nacin da kao osoba rastem jest da se
okruzim ljudima koji su pametniji od mene

4

Ponedjeljak, 04. August 2003

Evo da krenemo onda. Ovaj ti je prvi chapter chisto samo teorija, trazila si da cujes O tome sto te zanima. A evo ustvari ja mislim da ti uvodna strana i kaze sama o cemu se radi. Dalji chapteri su o koriscenju SQL statemants (database programiranja nema). Kopirao sam ti samo notes, jer za slike sa slajdova ne mogu da se prenesu. Reci mi posle ovog uvodnog chaptera da li odgovara da nastavim (kad god imam vremena). A ovaj chapter (lesson ti) ima sledeci AIM:

"In this lesson, you will gain an understanding of the relational database management system (RDBMS) and the object relational database management system (ORDBMS). You will also be introduced to the following:
SQL statements that are specific to Oracle
SQL*Plus, which is used for executing SQL and for formatting and reporting purposes
PL/SQL, which is Oracle’s procedural language"
mogu ja da se potpisem i bolje...

5

Ponedjeljak, 04. August 2003

here we go..

System Development Life Cycle
From concept to production, you can develop a database by using the system development life cycle, which contains multiple stages of development. This top-down, systematic approach to database development transforms business information requirements into an operational database.

Strategy and Analysis

Study and analyze the business requirements. Interview users and managers to identify the information requirements. Incorporate the enterprise and application mission statements as well as any future system specifications.
Build models of the system. Transfer the business narrative into a graphical representation of business information needs and rules. Confirm and refine the model with the analysts and experts.

Design

Design the database based on the model developed in the strategy and analysis phase.

Build and Document

Build the prototype system. Write and execute the commands to create the tables and supporting objects for the database.
Develop user documentation, help text, and operations manuals to support the use and operation of the system.

Transition

Refine the prototype. Move an application into production with user acceptance testing, conversion of existing data, and parallel operations. Make any modifications required.

Production

Roll out the system to the users. Operate the production system. Monitor its performance, and enhance and refine the system.

Note: The various phases of system development life cycle can be carried out iteratively. This course focuses on the build phase of the system development life cycle.

mogu ja da se potpisem i bolje...

6

Ponedjeljak, 04. August 2003

tebi ce ovo kao slajdovi izgledat :)

Storing Information

Every organization has some information needs. A library keeps a list of members, books, due dates, and fines. A company needs to save information about employees, departments, and salaries. These pieces of information are called data.
Organizations can store data on various media and in different formats—for example, a hard-copy document in a filing cabinet or data stored in electronic spreadsheets or in databases.
A database is an organized collection of information.
To manage databases, you need database management systems (DBMS). A DBMS is a program that stores, retrieves, and modifies data in the database on request. There are four main types of databases: hierarchical, network, relational, and more recently object relational.
Note: Oracle7 is a relational database management system and Oracle8 is an object relational database management system.
mogu ja da se potpisem i bolje...

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Ponedjeljak, 04. August 2003

continued

Relational Model

The principles of the relational model were first outlined by Dr. E.F. Codd in a June 1970 paper called “A Relational Model of Data for Large Shared Data Banks.” In this paper, Dr. Codd proposed the relational model for database systems.
The more popular models used at that time were hierarchical and network, or even simple flat file data structures. Relational database management systems (RDBMS) soon became very popular, especially for their ease of use and flexibility in structure. In addition, a number of innovative vendors, such as Oracle, supplemented the RDBMS with a suite of powerful application development and user products, providing a total solution.

Components of the Relational Model

Collections of objects or relations that store the data
A set of operators that can act on the relations to produce other relations
Data integrity for accuracy and consistency
mogu ja da se potpisem i bolje...

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Ponedjeljak, 04. August 2003

Definition of a Relational Database

A relational database uses relations or two-dimensional tables to store information.
For example, you might want to store information about all the employees in your company. In a relational database, you create several tables to store different pieces of information about your employees, such as an employee table, a department table, and a salary table.
mogu ja da se potpisem i bolje...

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Ponedjeljak, 04. August 2003

Data Models

Models are a cornerstone of design. Engineers build a model of a car to work out any details before putting it into production. In the same manner, system designers develop models to explore ideas and improve the understanding of the database design.

Purpose of Models

Models help communicate the concepts in people’s minds. They can be used to do the following:

Communicate

Categorize

Describe

Specify

Investigate

Evolve

Analyze

Imitate

The objective is to produce a model that fits a multitude of these uses, can be understood by an end user, and contains sufficient detail for a developer to build a database system.
mogu ja da se potpisem i bolje...

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Ponedjeljak, 04. August 2003

ER Modeling

In an effective system, data is divided into discrete categories or entities. An entity relationship (ER) model is an illustration of various entities in a business and the relationships between them. An ER model is derived from business specifications or narratives and built during the analysis phase of the system development life cycle. ER models separate the information required by a business from the activities performed within a business. Although businesses can change their activities, the type of information tends to remain constant. Therefore, the data structures also tend to be constant.

Benefits of ER Modeling

Documents information for the organization in a clear, precise format

Provides a clear picture of the scope of the information requirement

Provides an easily understood pictorial map for the database design

Offers an effective framework for integrating multiple applications

Key Components

Entity: A thing of significance about which information needs to be known. Examples are departments, employees, and orders.

Attribute: Something that describes or qualifies an entity. For example, for the employee entity, the attributes would be the employee number, name, job title, hire date, department number, and so on. Each of the attributes is either required or optional. This state is called optionality.

Relationship: A named association between entities showing optionality and degree. Examples are employees and departments, and orders and items.
mogu ja da se potpisem i bolje...

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Ponedjeljak, 04. August 2003

Entities

To represent an entity in a model, use the following conventions:

Soft box with any dimensions

Singular, unique entity name

Entity name in uppercase

Optional synonym names in uppercase within parentheses: ( )

Attributes

To represent an attribute in a model, use the following conventions:

Use singular names in lowercase

Tag mandatory attributes, or values that must be known, with an asterisk: *

Tag optional attributes, or values that may be known, with the letter o

Relationships

Each direction of the relationship contains:

A name, for example, taught by or assigned to

An optionality, either must be or may be

A degree, either one and only one or one or more

Note: The term cardinality is a synonym for the term degree.

Each source entity {may be | must be} relationship name {one and only one | one or more} destination entity.
Note: The convention is to read clockwise.

Unique Identifiers

A unique identifier (UID) is any combination of attributes or relationships, or both, that serves to distinguish occurrences of an entity. Each entity occurrence must be uniquely identifiable.
Tag each attribute that is part of the UID with a number symbol: #
Tag secondary UIDs with a number sign in parentheses: (#)
mogu ja da se potpisem i bolje...

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Ponedjeljak, 04. August 2003

Terminology Used in a Relational Database

A relational database can contain one or many tables. A table is the basic storage structure of an RDBMS. A table holds all the data necessary about something in the real world—for example, employees, invoices, or customers.
The slide shows the contents of the EMP table or relation. The numbers indicate the following:

(PAZNJA: OVO JE BAZA PODATAKA KOJU MI KORISTIMO A KOJA JE IZDATA OD STRANE AUTORA KNJIGE. TEBI MOZE DA POSLUZI JER CE SVI OPISANI PRIMERI BITI PO OVOJ BAZI URADJENI. A AKO TI TREBA JA MISLIM DA MOGU DA TI JE I POSALJEM)

1. A single row or tuple representing all data required for a particular employee. Each row in a table should be identified by a primary key, which allows no duplicate rows. The order of rows is insignificant; specify the row order when the data is retrieved.
2. A column or attribute containing the employee number, which is also the primary key. The employee number identifies a unique employee in the EMP table. A primary key must contain a value.
3. A column that is not a key value. A column represents one kind of data in a table; in the example, the job title of all the employees. Column order is insignificant when storing data; specify the column order when the data is retrieved.
4. A column containing the department number, which is also a foreign key. A foreign key is a column that defines how tables relate to each other. A foreign key refers to a primary key or a unique key in another table. In the example, DEPTNO uniquely identifies a department in the DEPT table.
5. A field can be found at the intersection of a row and a column. There can be only one value in it.
6. A field may have no value in it. This is called a null value. In the EMP table, only employees who have a role of salesman have a value in the COMM (commission) field.
mogu ja da se potpisem i bolje...

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Ponedjeljak, 04. August 2003

Relating Multiple Tables

Each table contains data that describes exactly one entity. For example, the EMP table contains information about employees. Categories of data are listed across the top of each table, and individual cases are listed below. Using a table format, you can readily visualize, understand, and use information.
Because data about different entities is stored in different tables, you may need to combine two or more tables to answer a particular question. For example, you may want to know the location of the department where an employee works. In this scenario, you need information from the EMP table (which contains data about employees) and the DEPT table (which contains information about departments). An RDBMS enables you to relate the data in one table to the data in another by using the foreign keys. A foreign key is a column or a set of columns that refer to a primary key in the same table or another table.
The ability to relate data in one table to data in another enables you to organize information in separate, manageable units. Employee data can be kept logically distinct from department data by storing it in a separate table.

Guidelines for Primary Keys and Foreign Keys

No duplicate values are allowed in a primary key.

Primary keys generally cannot be changed.

Foreign keys are based on data values and are purely logical, not physical, pointers.

A foreign key value must match an existing primary key value or unique key value, or else be null.

You cannot define foreign keys without existing primary (unique) keys.
mogu ja da se potpisem i bolje...

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Ponedjeljak, 04. August 2003

Properties of a Relational Database

In a relational database, you do not specify the access route to the tables, and you do not need to know how the data is arranged physically.
To access the database, you execute a structured query language (SQL) statement, which is the American National Standards Institute (ANSI) standard language for operating upon relational databases. The language contains a large set of operators for partitioning and combining relations. The database can be modified by using the SQL statements.



mogu ja da se potpisem i bolje...

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Ponedjeljak, 04. August 2003

Structured Query Language

SQL allows you to communicate with the server and has the following advantages:
Efficient
Easy to learn and use
Functionally complete (SQL allows you to define, retrieve, and manipulate data in the tables.)
mogu ja da se potpisem i bolje...

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Ponedjeljak, 04. August 2003

Relational Database Management System

Oracle provides a flexible RDBMS called Oracle7. Using its features, you can store and manage data with all the advantages of a relational structure plus PL/SQL, an engine that provides you with the ability to store and execute program units. The server offers the options of retrieving data based on optimization techniques. It includes security features that control how a database is accessed and used. Other features include consistency and protection of data through locking mechanisms.

Oracle applications may run on the same computer as the Oracle Server. Alternatively, you can run applications on a system local to the user and run the Oracle Server on another system (client-server architecture). In this client-server environment, a wide range of computing resources can be used. For example, a form-based airline reservation application can run on a client personal computer while accessing flight data that is conveniently managed by an Oracle Server on a central computer.
mogu ja da se potpisem i bolje...

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Ponedjeljak, 04. August 2003

Relational Database Management System

Oracle provides a flexible RDBMS called Oracle7. Using its features, you can store and manage data with all the advantages of a relational structure plus PL/SQL, an engine that provides you with the ability to store and execute program units. The server offers the options of retrieving data based on optimization techniques. It includes security features that control how a database is accessed and used. Other features include consistency and protection of data through locking mechanisms.
Oracle applications may run on the same computer as the Oracle Server. Alternatively, you can run applications on a system local to the user and run the Oracle Server on another system (client-server architecture). In this client-server environment, a wide range of computing resources can be used. For example, a form-based airline reservation application can run on a client personal computer while accessing flight data that is conveniently managed by an Oracle Server on a central computer.
mogu ja da se potpisem i bolje...

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Ponedjeljak, 04. August 2003

About Oracle8i

Oracle8i, the database for Internet computing, provides advanced tools to manage all types of data in Web sites.

It is much more than a simple relational data store. The Internet File System (iFS) combines the power of Oracle8i with the ease of use of a file system. It allows users to move all of their data into the Oracle8i database, where it can be stored and managed more efficiently. End users can easily access files and folders in Oracle iFS via a variety of protocols, such as HTML, FTP, and IMAP4, giving them universal access to their data.

Oracle8i interMedia allows users to web-enable their multi-media data—including image, text, audio, and video data. Oracle8i includes a robust, integrated, and scalable Java Virtual Machine within the server (Jserver), thus supporting Java in all tiers of applications. This eliminates the necessity of recompiling or modifying Java code when it is to be deployed on a different tier.

With the newly introduced resource management, the DBA can choose the best method to fit an application’s profile and workload. The extended features of parallel server and networking improves ease of system administration. The extended functionality of advanced replication results in better performance and improved security. Significant new functionalities have been added to languages.

Oracle8i provides full, native integration with Microsoft Transaction Server (MTS) in the Windows NT environment. Application development is simplified by the Oracle Application Wizard (AppWizard) for Visual Studio, which provides developers with a GUI tool for creating a Visual C++, Visual Interdev, or Visual Basic applications accessing data in an Oracle database.
mogu ja da se potpisem i bolje...

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Ponedjeljak, 04. August 2003

SQL Statements

Oracle SQL complies with industry-accepted standards. Oracle Corporation ensures future compliance with evolving standards by actively involving key personnel in SQL standards committees. Industry-accepted committees are the American National Standards Institute (ANSI) and the International Standards Organization (ISO). Both ANSI and ISO have accepted SQL as the standard language for relational databases.

About PL/SQL

Procedural Language/SQL (PL/SQL) is Oracle Corporation’s procedural language extension to SQL, the standard data access language for relational databases. PL/SQL offers modern software engineering features such as data encapsulation, exception handling, information hiding, and object orientation, and so brings state-of-the-art programming to the Oracle Server and Toolset.
PL/SQL incorporates many of the advanced features made in programming languages designed during the 1970s and 1980s. It allows the data manipulation and query statements of SQL to be included in block-structured and procedural units of code, making PL/SQL a powerful transaction processing language. With PL/SQL, you can use SQL statements to finesse Oracle data and PL/SQL control statements to process the data.

mogu ja da se potpisem i bolje...

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Ponedjeljak, 04. August 2003

e sad

Ovo je sve prepisivano sa notes od power point prezentacije. Potrudio sam se da napravim malko citljivijim nego sto bi to bio slucaj da sam samo copy i paste koristio. /recenice bez tacki na kraju su points na slajdovima (ili naslovi :) a ja sam ih razdvajao makar praznim redovima.

Ovo je bio intro chapter. Inace je sve sa intra to database. Ako radis advanced database, onda malo je tu pomoci od mene (jedino da me cekas jedno godinu dana :). Ono sto bi sledelo ovde jeste upotreba SQL/MYSQL prikazanih kroz primere sa napravljenom jednostavnom bazom podataka za tu svrhu.

Reci je li ti ovo pomaze sta. Ako da, onda kad god ja mogu cekace te ponesto ovde..

Pozdrav.
mogu ja da se potpisem i bolje...

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