success of Google and Database

The Google Guys Search for Success
-Google is one of the most successful companies on WWW.
--Search for Web pages, facts, quotes, etc.
--200 million queries a day

-Launched by a Sergey Brin and Larry Page (Stanford Ph.D. students)
--New approach in search technology
--Marks a page’s relevance by the number of times other related web pages link to it, not how often a word or phrase appeared on a page

The Electronic File Cabinet: Database Basics
What Good Is a Database?

-A database:
--A collection of information stored on computer disks

-Database software:
--Application software (like word processing and spreadsheet software)
--Designed to maintain databases (collections of information)

-Advantages offered by computerized databases:
--Make it easier to store large quantities of information
--Make it easier to retrieve information quickly and flexibly
--Make it easy to organize and reorganize information
--Make it easy to print and distribute information in a variety of ways

Database Anatomy

-Database program: a software tool for organizing the storage and retrieval of information

-Database: a collection of information stored in an organized form in a computer
--Typically composed of one or more tables
---A collection of related information
---A collection of records
--A record is the information relating to one person, product, or event.
--Each discrete piece of information in a record is a field.

--The type of information a field can hold is determined by its:
---Field type or
---Data type

--Database programs provide you with more than one way to view data:
---Form views
----Show one record at a time
---List views
----Display several records in lists similar to the way a spreadsheet displays data

--In any view, fields can be rearranged without changing the underlying data.

-Database Operations
--Import: receive data in the form of text files
--Browse: navigate through information
--Query: find records that match specific criteria
--Sort: rearrange records (alphabetically or numerically)
--Print reports, labels, and form letters: A report is an ordered list of selected records and fields in an easy-to-read format.
--Most modern database management programs support a standard language for programming complex queries called SQL (Structured Query Language).
---SQL is available for many database management systems.
---Programmers and sophisticated users don’t need to learn new languages when they work with new systems.
---The graphical user interfaces allow point-and-click queries that insulate users from the complexities of the query language.

-Special-Purpose Database Programs
--Specialized database software: preprogrammed for specific data storage and retrieval purposes
--Geographical information systems (GIS): include geographic and demographic data in map form
--Personal information manager (PIM): an electronic organizer
--Automates some or all of the following functions:
---Address/phone book
---Appointment calendar
---To-do list
---Miscellaneous notes
--Handheld computers can share information with applications such as iCalendar running on PCs and Macintoshes.

-From File Managers to Database Management Systems
--File manager: enables users to work with one file at a time
--Database management system (DBMS): manipulates data in a large collection of files, cross-referencing between files as needed
--A DBMS can be used interactively, or can be controlled directly by other programs.

What Makes a Database Relational?

-To most users, a relational database program is one that allows tables to be related to each other.
--Changes in one table are reflected in other tables automatically.
-To computer scientists, the term relational database has a technical definition related to:
--The underlying structure of the data
--The rules specifying how that data can be manipulated

The Many Faces of Databases

-Large databases often contain hundreds of interrelated tables.
-A database management system can shield users from the complex inner workings of the system, providing them with only the information and commands they need to get their jobs done.

Database Trends

-Batch processing: users accumulate transactions and input them into the computer in large batches
-Real-Time computing: allows instant access to information
-Interactive processing: has replaced batch processing for most applications
--Users can now interact with data through terminals, viewing and changing values online in real-time.
--Batch processing is still used for jobs in which it makes sense to do a lot of transactions at once.

Downsizing and Decentralizing
-Using a client/server approach
--Today many businesses use a client/server approach, using database servers.
--Users can take advantage of  the PC’s simple user interface and convenience, while still having access to data stored on large server systems.
-Data Mining:
--The discovery and extraction of hidden predictive information from large databases
--Uses statistical methods and artificial intelligence technology
---Locates trends and patterns in data that would have been overlooked by normal database queries
-Databases and the Web
--Information is available via a company’s Intranet and the Internet.
--HTML, the language used to construct most Web pages, wasn’t designed to build database queries.
--XML, a newer, more powerful data description language, is designed with industrial-strength database access in mind.
--Web database strategies revolve around directories.
--Directories are at the heart of many customer relationship management (CRM) systems—software systems for organizing and tracking information on customers.

Rules of Thumb: Dealing with Databases

-Choose the right tool for the job.
-Think about how you’ll get the information out before you put it in.
-Start with a plan, and be prepared to change your plan.
-Make your data consistent; inconsistencies can mess up sorting and make searching difficult.
-Databases are only as good as their data.
-Query with care.
-If at first you don’t succeed, try another approach.

Object-Oriented Databases
-Make database construction and usage more flexible
-Store software objects that contain procedures (or instructions) along with data
-Are often used in conjunction with object-oriented programming languages

An Example
-A database of images, containing a class for photos
-One instance of this class – one object for every photograph in the database
-Data associated with this object: photographer’s name, description of photo, copyright status, and the image itself
-One operation for the class – producing a thumbnail

Personal Data: All About You

-More than 15,000 specialized marketing databases contain 2,000,000,000 names.
-These databases contain characteristics like age, income, and religion.