CSI315CSI315 Web Development Technologies Continued

Data Data is an un-processed collection or representation of raw facts, concepts, or instructions in a manner suitable for communication, interpretation, or processing by humans or by automatic means. It can be defined as unprocessed information. Data that has been interpreted, translated, or transformed to reveal the underlying meaning is called information. Information is the result of processing, manipulating and organizing data in a way that adds to the knowledge of the person receiving Data is converted into information, and information is converted into knowledge.

The Data Layer All of the web technologies at the Data Layer define, describe, or standardize one or more of the data characteristics: –Data types (letters, numbers, dates, ints, floats. strings ) –Data descriptions (reference keywords) –Data formats (DD/MM/YYYY, $ ) –Data values Data is stored in databases across the Internet

The Database A logical collection of interrelated data organized to meet the needs and structure of an organization. A collection of information organized and presented to serve a specific purpose. A computerized database is an updated, organized file of machine readable information that is rapidly searched and retrieved by computer. A collection of related electronic records in a standardized format, searchable in a variety of ways, such as title, author, subject, and keyword.

Databases Databases are designed to offer an organized mechanism for storing, managing and retrieving information. Data from the database extracted from the internal (Finance, Marketing, Production, Personnel etc.) and external sources like industry data, regional employment data etc. Data may organized in one or more separate databases or in a data warehouse, or a special independent database.

Database Actions Actions that you can perform to a database Retrieve all records that match certain criteria Update records in bulk Cross-reference records in different tables Perform complex aggregate calculations

Database Management System (DBMS) A collection of computer programs that allow creation, storage, modification, and extraction of information from the database. Captures data for inclusion in the database Updates(adds, deletes, edits, changes) data records and files Interrelates data from different sources Retrieves data from the database for queries and reports Provides comprehensive data security-access, recovery Performs complex data manipulation tasks based on queries Tracks data within the DSS Manages data through a data dictionary

The Query Facility Performs queries on the data It accepts data from other DSS components Determines how the request can be filled ( consults data dictionary) Formulates the detailed request Returns the results to the issuer of request

Data Directory A catalog of of all data in the database Contains data item definitions, their sources and exact meaning Supports updates like additions and deletions

Web Databases(OLAP) Analytic databases (a.k.a. OLAP- On Line Analytical Processing) are primarily static, read-only databases which store archived, historical data used for analysis. They enable analysts, managers and executives to gain insight into data through fast, consistent, interactive access. For example a user could –request spreadsheet analysis showing all of a company's products sold in a certain month –compare revenue figures with those for the same products another month –see a comparison of other product sales in another branch/company in the same time period

Web Databases (OLTP) Operational databases (a.k.a. OLTP On Line Transaction Processing Databases that allow the real-time processing of SQL transactions to support e-commerce and other time-critical applications. This type of processing is known as online transaction processing (OLTP ) An OLTP database has Read and Write access. This is where transactions are actually entered, modified, and/or deleted.

Data model A data model is a "description" of both a container for data and a methodology for storing and retrieving data from that container. Data models are abstractions, often at times mathematical algorithms and concepts Used for presenting entities of interest and their relationships in the database

Database Models Relational Database : most popular form. Table = data file Data collected in 2-dimensional tabular form. Columns(field) e.g Data field called Cu. Name,ID, Address etc. ), rows (records made up of several field) Data files may be related by a common field forming a relation.

Hierarchical Databases Data items arranged in a top down fashion Logical links between data items e.g

Database Models Cntd. Networked Databases Structure allows dependencies among elements Saves storage space through sharing of data items

Database Models Cntd O-O Databases Defines data as objects and models natural relationships between objects(inheritance, encapsulation, behavior etc.) Uses a hierarchy of classes and sub-subclasses Multimedia based databases Uses a variety of formats in addition to text and numeric fields (bitmaps,video clips, sound, virtual reality)

Database Connectivity two ways connecting to the database directly using a command shell connecting to the database over the network using sockets (if that database allows such interaction).

Database Issues: Online Database : A collection of information organized in such a way that a website visitor can quickly select desired pieces of data. Uses include: Show visitors your vast inventory by price, category and pictures. Let customers use a search function to quickly find a product or service. A must for e-commerce websites that carry 10 or more items. Quickly change and update your website through the administration tool of the website. Store information.

Database Issues (Tutorial) Data warehousing Data mining