Submit Search
Upload
Ch8
•
Download as PPT, PDF
•
0 likes
•
125 views
Subramanyam Neelam
Follow
normalization review slides
Read less
Read more
Education
Report
Share
Report
Share
1 of 52
Download now
Recommended
ch8
ch8
KITE www.kitecolleges.com
Ch9
Ch9
Hitesh Mohapatra
Web Database
Web Database
idroos7
Deep Web: Databases on the Web
Deep Web: Databases on the Web
Denis Shestakov
Data services
Data services
Gourav Nagar
The Story of How an Oracle Classic Stronghold successfully embraced SOA
The Story of How an Oracle Classic Stronghold successfully embraced SOA
Lucas Jellema
The Story of How an Oracle Classic Stronghold successfully embraced SOA (ODTU...
The Story of How an Oracle Classic Stronghold successfully embraced SOA (ODTU...
Lucas Jellema
Exchanging the Status between Clients of Geospatial Web Services and GIS appl...
Exchanging the Status between Clients of Geospatial Web Services and GIS appl...
Paula Díaz
Recommended
ch8
ch8
KITE www.kitecolleges.com
Ch9
Ch9
Hitesh Mohapatra
Web Database
Web Database
idroos7
Deep Web: Databases on the Web
Deep Web: Databases on the Web
Denis Shestakov
Data services
Data services
Gourav Nagar
The Story of How an Oracle Classic Stronghold successfully embraced SOA
The Story of How an Oracle Classic Stronghold successfully embraced SOA
Lucas Jellema
The Story of How an Oracle Classic Stronghold successfully embraced SOA (ODTU...
The Story of How an Oracle Classic Stronghold successfully embraced SOA (ODTU...
Lucas Jellema
Exchanging the Status between Clients of Geospatial Web Services and GIS appl...
Exchanging the Status between Clients of Geospatial Web Services and GIS appl...
Paula Díaz
Dos1
Dos1
Avinash Buddana
Cloud computing by Luqman
Cloud computing by Luqman
Luqman Shareef
Service Oriented Architecture Luqman
Service Oriented Architecture Luqman
Luqman Shareef
Introduction to webservices
Introduction to webservices
Gagandeep Singh
R2 microsoft ado.net data services datasheet
R2 microsoft ado.net data services datasheet
Klaudiia Jacome
B2STAGE Installation| www.eudat.eu |
B2STAGE Installation| www.eudat.eu |
EUDAT
CHC 2009 - The Ccls Approach To Building M Pages
CHC 2009 - The Ccls Approach To Building M Pages
Lucile Packard Children's Hospital at Stanford
E - BUSINESS AND ACCOUNTING.
E - BUSINESS AND ACCOUNTING.
Abhishek Kulkarni
Web 2 0 Tools
Web 2 0 Tools
ramesh kumar
Web services2014
Web services2014
Lee Schlenker
Data Virtualization Primer - Introduction
Data Virtualization Primer - Introduction
Kenneth Peeples
Web Services
Web Services
chidi
Sharepoint 2010 enterprise content management features
Sharepoint 2010 enterprise content management features
Manish Rawat
ESM_ServiceLayer_DevGuide_1.0.pdf
ESM_ServiceLayer_DevGuide_1.0.pdf
Protect724v2
Web 2 0 Fullfeatures
Web 2 0 Fullfeatures
Ratna Prashanth
Sdmx Tools
Sdmx Tools
Vincenzo Patruno
Azure Platform
Azure Platform
Wes Yanaga
Normalization
Normalization
Subramanyam Neelam
Ch1 intro
Ch1 intro
Subramanyam Neelam
Mca ii-dbms-u-v-transaction management
Mca ii-dbms-u-v-transaction management
Rai University
Normalization
Normalization
Nittaya Intarat
Directed Acyclic Graph
Directed Acyclic Graph
AJAL A J
More Related Content
What's hot
Dos1
Dos1
Avinash Buddana
Cloud computing by Luqman
Cloud computing by Luqman
Luqman Shareef
Service Oriented Architecture Luqman
Service Oriented Architecture Luqman
Luqman Shareef
Introduction to webservices
Introduction to webservices
Gagandeep Singh
R2 microsoft ado.net data services datasheet
R2 microsoft ado.net data services datasheet
Klaudiia Jacome
B2STAGE Installation| www.eudat.eu |
B2STAGE Installation| www.eudat.eu |
EUDAT
CHC 2009 - The Ccls Approach To Building M Pages
CHC 2009 - The Ccls Approach To Building M Pages
Lucile Packard Children's Hospital at Stanford
E - BUSINESS AND ACCOUNTING.
E - BUSINESS AND ACCOUNTING.
Abhishek Kulkarni
Web 2 0 Tools
Web 2 0 Tools
ramesh kumar
Web services2014
Web services2014
Lee Schlenker
Data Virtualization Primer - Introduction
Data Virtualization Primer - Introduction
Kenneth Peeples
Web Services
Web Services
chidi
Sharepoint 2010 enterprise content management features
Sharepoint 2010 enterprise content management features
Manish Rawat
ESM_ServiceLayer_DevGuide_1.0.pdf
ESM_ServiceLayer_DevGuide_1.0.pdf
Protect724v2
Web 2 0 Fullfeatures
Web 2 0 Fullfeatures
Ratna Prashanth
Sdmx Tools
Sdmx Tools
Vincenzo Patruno
Azure Platform
Azure Platform
Wes Yanaga
What's hot
(17)
Dos1
Dos1
Cloud computing by Luqman
Cloud computing by Luqman
Service Oriented Architecture Luqman
Service Oriented Architecture Luqman
Introduction to webservices
Introduction to webservices
R2 microsoft ado.net data services datasheet
R2 microsoft ado.net data services datasheet
B2STAGE Installation| www.eudat.eu |
B2STAGE Installation| www.eudat.eu |
CHC 2009 - The Ccls Approach To Building M Pages
CHC 2009 - The Ccls Approach To Building M Pages
E - BUSINESS AND ACCOUNTING.
E - BUSINESS AND ACCOUNTING.
Web 2 0 Tools
Web 2 0 Tools
Web services2014
Web services2014
Data Virtualization Primer - Introduction
Data Virtualization Primer - Introduction
Web Services
Web Services
Sharepoint 2010 enterprise content management features
Sharepoint 2010 enterprise content management features
ESM_ServiceLayer_DevGuide_1.0.pdf
ESM_ServiceLayer_DevGuide_1.0.pdf
Web 2 0 Fullfeatures
Web 2 0 Fullfeatures
Sdmx Tools
Sdmx Tools
Azure Platform
Azure Platform
Viewers also liked
Normalization
Normalization
Subramanyam Neelam
Ch1 intro
Ch1 intro
Subramanyam Neelam
Mca ii-dbms-u-v-transaction management
Mca ii-dbms-u-v-transaction management
Rai University
Normalization
Normalization
Nittaya Intarat
Directed Acyclic Graph
Directed Acyclic Graph
AJAL A J
SQL Server Transaction Management
SQL Server Transaction Management
Mark Ginnebaugh
Code optimization
Code optimization
veena venugopal
Mca ii-dbms- u-i-introductory concepts of dbms
Mca ii-dbms- u-i-introductory concepts of dbms
Rai University
The dag representation of basic blocks
The dag representation of basic blocks
Shabeen Taj
Hybrid Cloud Computing (IBM System z)
Hybrid Cloud Computing (IBM System z)
IBM Danmark
code optimization
code optimization
Sanjeev Raaz
Code Generation
Code Generation
PrabuPappuR
Code generator
Code generator
Tech_MX
Normalization
Normalization
Venkata Ramireddy Chirra
Peephole optimization techniques in compiler design
Peephole optimization techniques in compiler design
Anul Chaudhary
Three address code In Compiler Design
Three address code In Compiler Design
Shine Raj
DBMS - Normalization
DBMS - Normalization
Jitendra Tomar
Dbms
Dbms
sevtap87
Database Management Systems (DBMS)
Database Management Systems (DBMS)
Dimara Hakim
Viewers also liked
(19)
Normalization
Normalization
Ch1 intro
Ch1 intro
Mca ii-dbms-u-v-transaction management
Mca ii-dbms-u-v-transaction management
Normalization
Normalization
Directed Acyclic Graph
Directed Acyclic Graph
SQL Server Transaction Management
SQL Server Transaction Management
Code optimization
Code optimization
Mca ii-dbms- u-i-introductory concepts of dbms
Mca ii-dbms- u-i-introductory concepts of dbms
The dag representation of basic blocks
The dag representation of basic blocks
Hybrid Cloud Computing (IBM System z)
Hybrid Cloud Computing (IBM System z)
code optimization
code optimization
Code Generation
Code Generation
Code generator
Code generator
Normalization
Normalization
Peephole optimization techniques in compiler design
Peephole optimization techniques in compiler design
Three address code In Compiler Design
Three address code In Compiler Design
DBMS - Normalization
DBMS - Normalization
Dbms
Dbms
Database Management Systems (DBMS)
Database Management Systems (DBMS)
Similar to Ch8
ch9.ppt
ch9.ppt
ChinnuJose3
Ch8
Ch8
Subhankar Chowdhury
Ch21
Ch21
Welly Dian Astika
21. Application Development and Administration in DBMS
21. Application Development and Administration in DBMS
koolkampus
Introduction to Web Architecture
Introduction to Web Architecture
Chamnap Chhorn
Asp.netrole
Asp.netrole
mani bhushan
Cloud Computing With Windows Azure
Cloud Computing With Windows Azure
ChadAmberg
web services8 (1).pdf for computer science
web services8 (1).pdf for computer science
optimusnotch44
Ch17
Ch17
suman banoth
World Wide Web(WWW)
World Wide Web(WWW)
Pratik Tambekar
Application layer assignments
Application layer assignments
Isaac Akingbala
Ch20
Ch20
Aravindharamanan S
Fm 2
Fm 2
sambavade
Azure Overview Csco
Azure Overview Csco
rajramab
An Introduction to On-Demand, Web-Based Publishing
An Introduction to On-Demand, Web-Based Publishing
STC-Philadelphia Metro Chapter
WP Chap 1 & 2.pptx
WP Chap 1 & 2.pptx
AnkitaChauhan79
9781423903055 ppt ch08
9781423903055 ppt ch08
临枫 盖
HTTP and Website Architecture and Middleware
HTTP and Website Architecture and Middleware
Abdul Jalil Tamjid
Migrating Apps To Azure
Migrating Apps To Azure
Harish Ranganathan
C# Unit5 Notes
C# Unit5 Notes
Sudarshan Dhondaley
Similar to Ch8
(20)
ch9.ppt
ch9.ppt
Ch8
Ch8
Ch21
Ch21
21. Application Development and Administration in DBMS
21. Application Development and Administration in DBMS
Introduction to Web Architecture
Introduction to Web Architecture
Asp.netrole
Asp.netrole
Cloud Computing With Windows Azure
Cloud Computing With Windows Azure
web services8 (1).pdf for computer science
web services8 (1).pdf for computer science
Ch17
Ch17
World Wide Web(WWW)
World Wide Web(WWW)
Application layer assignments
Application layer assignments
Ch20
Ch20
Fm 2
Fm 2
Azure Overview Csco
Azure Overview Csco
An Introduction to On-Demand, Web-Based Publishing
An Introduction to On-Demand, Web-Based Publishing
WP Chap 1 & 2.pptx
WP Chap 1 & 2.pptx
9781423903055 ppt ch08
9781423903055 ppt ch08
HTTP and Website Architecture and Middleware
HTTP and Website Architecture and Middleware
Migrating Apps To Azure
Migrating Apps To Azure
C# Unit5 Notes
C# Unit5 Notes
Recently uploaded
Earth Day Presentation wow hello nice great
Earth Day Presentation wow hello nice great
YousafMalik24
Types of Journalistic Writing Grade 8.pptx
Types of Journalistic Writing Grade 8.pptx
Eyham Joco
Difference Between Search & Browse Methods in Odoo 17
Difference Between Search & Browse Methods in Odoo 17
Celine George
ECONOMIC CONTEXT - LONG FORM TV DRAMA - PPT
ECONOMIC CONTEXT - LONG FORM TV DRAMA - PPT
iammrhaywood
Gas measurement O2,Co2,& ph) 04/2024.pptx
Gas measurement O2,Co2,& ph) 04/2024.pptx
Dr.Ibrahim Hassaan
Alper Gobel In Media Res Media Component
Alper Gobel In Media Res Media Component
InMediaRes1
Meghan Sutherland In Media Res Media Component
Meghan Sutherland In Media Res Media Component
InMediaRes1
Painted Grey Ware.pptx, PGW Culture of India
Painted Grey Ware.pptx, PGW Culture of India
Virag Sontakke
Hierarchy of management that covers different levels of management
Hierarchy of management that covers different levels of management
mkooblal
How to Configure Email Server in Odoo 17
How to Configure Email Server in Odoo 17
Celine George
EPANDING THE CONTENT OF AN OUTLINE using notes.pptx
EPANDING THE CONTENT OF AN OUTLINE using notes.pptx
RaymartEstabillo3
Model Call Girl in Tilak Nagar Delhi reach out to us at 🔝9953056974🔝
Model Call Girl in Tilak Nagar Delhi reach out to us at 🔝9953056974🔝
9953056974 Low Rate Call Girls In Saket, Delhi NCR
Proudly South Africa powerpoint Thorisha.pptx
Proudly South Africa powerpoint Thorisha.pptx
thorishapillay1
CELL CYCLE Division Science 8 quarter IV.pptx
CELL CYCLE Division Science 8 quarter IV.pptx
JiesonDelaCerna
Introduction to AI in Higher Education_draft.pptx
Introduction to AI in Higher Education_draft.pptx
pboyjonauth
Final demo Grade 9 for demo Plan dessert.pptx
Final demo Grade 9 for demo Plan dessert.pptx
AvyJaneVismanos
Crayon Activity Handout For the Crayon A
Crayon Activity Handout For the Crayon A
UnboundStockton
Framing an Appropriate Research Question 6b9b26d93da94caf993c038d9efcdedb.pdf
Framing an Appropriate Research Question 6b9b26d93da94caf993c038d9efcdedb.pdf
UjwalaBharambe
Procuring digital preservation CAN be quick and painless with our new dynamic...
Procuring digital preservation CAN be quick and painless with our new dynamic...
Jisc
Organic Name Reactions for the students and aspirants of Chemistry12th.pptx
Organic Name Reactions for the students and aspirants of Chemistry12th.pptx
VS Mahajan Coaching Centre
Recently uploaded
(20)
Earth Day Presentation wow hello nice great
Earth Day Presentation wow hello nice great
Types of Journalistic Writing Grade 8.pptx
Types of Journalistic Writing Grade 8.pptx
Difference Between Search & Browse Methods in Odoo 17
Difference Between Search & Browse Methods in Odoo 17
ECONOMIC CONTEXT - LONG FORM TV DRAMA - PPT
ECONOMIC CONTEXT - LONG FORM TV DRAMA - PPT
Gas measurement O2,Co2,& ph) 04/2024.pptx
Gas measurement O2,Co2,& ph) 04/2024.pptx
Alper Gobel In Media Res Media Component
Alper Gobel In Media Res Media Component
Meghan Sutherland In Media Res Media Component
Meghan Sutherland In Media Res Media Component
Painted Grey Ware.pptx, PGW Culture of India
Painted Grey Ware.pptx, PGW Culture of India
Hierarchy of management that covers different levels of management
Hierarchy of management that covers different levels of management
How to Configure Email Server in Odoo 17
How to Configure Email Server in Odoo 17
EPANDING THE CONTENT OF AN OUTLINE using notes.pptx
EPANDING THE CONTENT OF AN OUTLINE using notes.pptx
Model Call Girl in Tilak Nagar Delhi reach out to us at 🔝9953056974🔝
Model Call Girl in Tilak Nagar Delhi reach out to us at 🔝9953056974🔝
Proudly South Africa powerpoint Thorisha.pptx
Proudly South Africa powerpoint Thorisha.pptx
CELL CYCLE Division Science 8 quarter IV.pptx
CELL CYCLE Division Science 8 quarter IV.pptx
Introduction to AI in Higher Education_draft.pptx
Introduction to AI in Higher Education_draft.pptx
Final demo Grade 9 for demo Plan dessert.pptx
Final demo Grade 9 for demo Plan dessert.pptx
Crayon Activity Handout For the Crayon A
Crayon Activity Handout For the Crayon A
Framing an Appropriate Research Question 6b9b26d93da94caf993c038d9efcdedb.pdf
Framing an Appropriate Research Question 6b9b26d93da94caf993c038d9efcdedb.pdf
Procuring digital preservation CAN be quick and painless with our new dynamic...
Procuring digital preservation CAN be quick and painless with our new dynamic...
Organic Name Reactions for the students and aspirants of Chemistry12th.pptx
Organic Name Reactions for the students and aspirants of Chemistry12th.pptx
Ch8
1.
Database System Concepts ©Silberschatz,
Korth and Sudarshan See www.db-book.com for conditions on re-use ©Silberschatz, Korth and SudarshanDatabase System Concepts Chapter 8: Application Design andChapter 8: Application Design and DevelopmentDevelopment
2.
©Silberschatz, Korth and
Sudarshan8.2atabase System Concepts - 5th Edition, Oct 23, 2006. Chapter 8: Application Design andChapter 8: Application Design and DevelopmentDevelopment User Interfaces and Tools Web Interfaces to Databases Web Fundamentals Servlets and JSP Building Large Web Applications Triggers Authorization in SQL Application Security
3.
©Silberschatz, Korth and
Sudarshan8.3atabase System Concepts - 5th Edition, Oct 23, 2006. User Interfaces and ToolsUser Interfaces and Tools Most database users do not use a query language like SQL. Forms Graphical user interfaces Report generators Data analysis tools (see Chapter 18) Many interfaces are Web-based Back-end (Web server) uses such technologies as Java servlets Java Server Pages (JSP) Active Server Pages (ASP)
4.
©Silberschatz, Korth and
Sudarshan8.4atabase System Concepts - 5th Edition, Oct 23, 2006. The World Wide WebThe World Wide Web The Web is a distributed information system based on hypertext. Most Web documents are hypertext documents formatted via the HyperText Markup Language (HTML) HTML documents contain text along with font specifications, and other formatting instructions hypertext links to other documents, which can be associated with regions of the text. forms, enabling users to enter data which can then be sent back to the Web server
5.
©Silberschatz, Korth and
Sudarshan8.5atabase System Concepts - 5th Edition, Oct 23, 2006. A formatted reportA formatted report
6.
©Silberschatz, Korth and
Sudarshan8.6atabase System Concepts - 5th Edition, Oct 23, 2006. Web Interfaces to DatabasesWeb Interfaces to Databases Why interface databases to the Web? 1. Web browsers have become the de-facto standard user interface to databases Enable large numbers of users to access databases from anywhere Avoid the need for downloading/installing specialized code, while providing a good graphical user interface Examples: banks, airline and rental car reservations, university course registration and grading, an so on.
7.
©Silberschatz, Korth and
Sudarshan8.7atabase System Concepts - 5th Edition, Oct 23, 2006. Web Interfaces to Database (Cont.)Web Interfaces to Database (Cont.) 2. Dynamic generation of documents Limitations of static HTML documents Cannot customize fixed Web documents for individual users. Problematic to update Web documents, especially if multiple Web documents replicate data. Solution: Generate Web documents dynamically from data stored in a database. Can tailor the display based on user information stored in the database. – E.g. tailored ads, tailored weather and local news, … Displayed information is up-to-date, unlike the static Web pages – E.g. stock market information, ..
8.
©Silberschatz, Korth and
Sudarshan8.8atabase System Concepts - 5th Edition, Oct 23, 2006. Uniform Resources LocatorsUniform Resources Locators In the Web, functionality of pointers is provided by Uniform Resource Locators (URLs). URL example: http://www.bell-labs.com/topics/book/db-book The first part indicates how the document is to be accessed “http” indicates that the document is to be accessed using the Hyper Text Transfer Protocol. The second part gives the unique name of a machine on the Internet. The rest of the URL identifies the document within the machine. The local identification can be: The path name of a file on the machine, or An identifier (path name) of a program, plus arguments to be passed to the program – E.g. http://www.google.com/search?q=silberschatz
9.
©Silberschatz, Korth and
Sudarshan8.9atabase System Concepts - 5th Edition, Oct 23, 2006. HTML and HTTPHTML and HTTP HTML provides formatting, hypertext link, and image display features. HTML also provides input features Select from a set of options – Pop-up menus, radio buttons, check lists Enter values – Text boxes Filled in input sent back to the server, to be acted upon by an executable at the server HyperText Transfer Protocol (HTTP) used for communication with the Web server
10.
©Silberschatz, Korth and
Sudarshan8.10atabase System Concepts - 5th Edition, Oct 23, 2006. Sample HTML Source TextSample HTML Source Text <html> <body> <table border cols = 3> <tr> <td> A-101 </td> <td> Downtown </td> <td> 500 </td> </tr> … </table> <center> The <i>account</i> relation </center> <form action=“BankQuery” method=get> Select account/loan and enter number <br> <select name=“type”> <option value=“account” selected> Account <option> value=“Loan”> Loan </select> <input type=text size=5 name=“number”> <input type=submit value=“submit”> </form> </body> </html>
11.
©Silberschatz, Korth and
Sudarshan8.11atabase System Concepts - 5th Edition, Oct 23, 2006. Display of Sample HTML SourceDisplay of Sample HTML Source
12.
©Silberschatz, Korth and
Sudarshan8.12atabase System Concepts - 5th Edition, Oct 23, 2006. Client Side Scripting and AppletsClient Side Scripting and Applets Browsers can fetch certain scripts (client-side scripts) or programs along with documents, and execute them in “safe mode” at the client site Javascript Macromedia Flash and Shockwave for animation/games VRML Applets Client-side scripts/programs allow documents to be active E.g., animation by executing programs at the local site E.g. ensure that values entered by users satisfy some correctness checks Permit flexible interaction with the user. Executing programs at the client site speeds up interaction by avoiding many round trips to server
13.
©Silberschatz, Korth and
Sudarshan8.13atabase System Concepts - 5th Edition, Oct 23, 2006. Client Side Scripting and SecurityClient Side Scripting and Security Security mechanisms needed to ensure that malicious scripts do not cause damage to the client machine Easy for limited capability scripting languages, harder for general purpose programming languages like Java E.g. Java’s security system ensures that the Java applet code does not make any system calls directly Disallows dangerous actions such as file writes Notifies the user about potentially dangerous actions, and allows the option to abort the program or to continue execution.
14.
©Silberschatz, Korth and
Sudarshan8.14atabase System Concepts - 5th Edition, Oct 23, 2006. Web ServersWeb Servers A Web server can easily serve as a front end to a variety of information services. The document name in a URL may identify an executable program, that, when run, generates a HTML document. When a HTTP server receives a request for such a document, it executes the program, and sends back the HTML document that is generated. The Web client can pass extra arguments with the name of the document. To install a new service on the Web, one simply needs to create and install an executable that provides that service. The Web browser provides a graphical user interface to the information service. Common Gateway Interface (CGI): a standard interface between web and application server
15.
©Silberschatz, Korth and
Sudarshan8.15atabase System Concepts - 5th Edition, Oct 23, 2006. Three-Tier Web ArchitectureThree-Tier Web Architecture
16.
©Silberschatz, Korth and
Sudarshan8.16atabase System Concepts - 5th Edition, Oct 23, 2006. Two-Tier Web ArchitectureTwo-Tier Web Architecture Multiple levels of indirection have overheads Alternative: two-tier architecture
17.
©Silberschatz, Korth and
Sudarshan8.17atabase System Concepts - 5th Edition, Oct 23, 2006. HTTP and SessionsHTTP and Sessions The HTTP protocol is connectionless That is, once the server replies to a request, the server closes the connection with the client, and forgets all about the request In contrast, Unix logins, and JDBC/ODBC connections stay connected until the client disconnects retaining user authentication and other information Motivation: reduces load on server operating systems have tight limits on number of open connections on a machine Information services need session information E.g. user authentication should be done only once per session Solution: use a cookie
18.
©Silberschatz, Korth and
Sudarshan8.18atabase System Concepts - 5th Edition, Oct 23, 2006. Sessions and CookiesSessions and Cookies A cookie is a small piece of text containing identifying information Sent by server to browser on first interaction Sent by browser to the server that created the cookie on further interactions part of the HTTP protocol Server saves information about cookies it issued, and can use it when serving a request E.g., authentication information, and user preferences Cookies can be stored permanently or for a limited time
19.
©Silberschatz, Korth and
Sudarshan8.19atabase System Concepts - 5th Edition, Oct 23, 2006. ServletsServlets Java Servlet specification defines an API for communication between the Web server and application program E.g. methods to get parameter values and to send HTML text back to client Application program (also called a servlet) is loaded into the Web server Two-tier model Each request spawns a new thread in the Web server thread is closed once the request is serviced Servlet API provides a getSession() method Sets a cookie on first interaction with browser, and uses it to identify session on further interactions Provides methods to store and look-up per-session information E.g. user name, preferences, ..
20.
©Silberschatz, Korth and
Sudarshan8.20atabase System Concepts - 5th Edition, Oct 23, 2006. Example Servlet CodeExample Servlet Code Public class BankQuery(Servlet extends HttpServlet { public void doGet(HttpServletRequest request, HttpServletResponse result) throws ServletException, IOException { String type = request.getParameter(“type”); String number = request.getParameter(“number”); …code to find the loan amount/account balance … …using JDBC to communicate with the database.. …we assume the value is stored in the variable balance result.setContentType(“text/html”); PrintWriter out = result.getWriter( ); out.println(“<HEAD><TITLE>Query Result</TITLE></HEAD>”); out.println(“<BODY>”); out.println(“Balance on “ + type + number + “=“ + balance); out.println(“</BODY>”); out.close ( ); } }
21.
©Silberschatz, Korth and
Sudarshan8.21atabase System Concepts - 5th Edition, Oct 23, 2006. Server-Side ScriptingServer-Side Scripting Server-side scripting simplifies the task of connecting a database to the Web Define a HTML document with embedded executable code/SQL queries. Input values from HTML forms can be used directly in the embedded code/SQL queries. When the document is requested, the Web server executes the embedded code/SQL queries to generate the actual HTML document. Numerous server-side scripting languages JSP, Server-side Javascript, ColdFusion Markup Language (cfml), PHP, Jscript General purpose scripting languages: VBScript, Perl, Python
22.
©Silberschatz, Korth and
Sudarshan8.22atabase System Concepts - 5th Edition, Oct 23, 2006. Improving Web Server PerformanceImproving Web Server Performance Performance is an issue for popular Web sites May be accessed by millions of users every day, thousands of requests per second at peak time Caching techniques used to reduce cost of serving pages by exploiting commonalities between requests At the server site: Caching of JDBC connections between servlet requests Caching results of database queries – Cached results must be updated if underlying database changes Caching of generated HTML At the client’s network Caching of pages by Web proxy
23.
©Silberschatz, Korth and
Sudarshan8.23atabase System Concepts - 5th Edition, Oct 23, 2006. TriggersTriggers A trigger is a statement that is executed automatically by the system as a side effect of a modification to the database. To design a trigger mechanism, we must: Specify the conditions under which the trigger is to be executed. Specify the actions to be taken when the trigger executes. Triggers introduced to SQL standard in SQL:1999, but supported even earlier using non-standard syntax by most databases.
24.
©Silberschatz, Korth and
Sudarshan8.24atabase System Concepts - 5th Edition, Oct 23, 2006. Trigger ExampleTrigger Example Suppose that instead of allowing negative account balances, the bank deals with overdrafts by setting the account balance to zero creating a loan in the amount of the overdraft giving this loan a loan number identical to the account number of the overdrawn account The condition for executing the trigger is an update to the account relation that results in a negative balance value.
25.
©Silberschatz, Korth and
Sudarshan8.25atabase System Concepts - 5th Edition, Oct 23, 2006. Trigger Example in SQL:1999Trigger Example in SQL:1999 create trigger overdraft-trigger after update on account referencing new row as nrow for each row when nrow.balance < 0 begin atomic insert into borrower (select customer-name, account-number from depositor where nrow.account-number = depositor.account-number); insert into loan values (n.row.account-number, nrow.branch-name, – nrow.balance); update account set balance = 0 where account.account-number = nrow.account-number end
26.
©Silberschatz, Korth and
Sudarshan8.26atabase System Concepts - 5th Edition, Oct 23, 2006. Triggering Events and Actions inTriggering Events and Actions in SQLSQL Triggering event can be insert, delete or update Triggers on update can be restricted to specific attributes E.g. create trigger overdraft-trigger after update of balance on account Values of attributes before and after an update can be referenced referencing old row as : for deletes and updates referencing new row as : for inserts and updates Triggers can be activated before an event, which can serve as extra constraints. E.g. convert blanks to null. create trigger setnull-trigger before update on r referencing new row as nrow for each row when nrow.phone-number = ‘ ‘ set nrow.phone-number = null
27.
©Silberschatz, Korth and
Sudarshan8.27atabase System Concepts - 5th Edition, Oct 23, 2006. Statement Level TriggersStatement Level Triggers Instead of executing a separate action for each affected row, a single action can be executed for all rows affected by a transaction Use for each statement instead of for each row Use referencing old table or referencing new table to refer to temporary tables (called transition tables) containing the affected rows Can be more efficient when dealing with SQL statements that update a large number of rows
28.
©Silberschatz, Korth and
Sudarshan8.28atabase System Concepts - 5th Edition, Oct 23, 2006. External World ActionsExternal World Actions We sometimes require external world actions to be triggered on a database update E.g. re-ordering an item whose quantity in a warehouse has become small, or turning on an alarm light, Triggers cannot be used to directly implement external-world actions, BUT Triggers can be used to record actions-to-be-taken in a separate table Have an external process that repeatedly scans the table, carries out external-world actions and deletes action from table E.g. Suppose a warehouse has the following tables inventory (item, level ): How much of each item is in the warehouse minlevel (item, level ) : What is the minimum desired level of each item reorder (item, amount ): What quantity should we re-order at a time orders (item, amount ) : Orders to be placed (read by external process)
29.
©Silberschatz, Korth and
Sudarshan8.29atabase System Concepts - 5th Edition, Oct 23, 2006. External World Actions (Cont.)External World Actions (Cont.) create trigger reorder-trigger after update of amount on inventory referencing old row as orow, new row as nrow for each row when nrow.level < = (select level from minlevel where minlevel.item = orow.item) and orow.level > (select level from minlevel where minlevel.item = orow.item) begin insert into orders (select item, amount from reorder where reorder.item = orow.item) end
30.
©Silberschatz, Korth and
Sudarshan8.30atabase System Concepts - 5th Edition, Oct 23, 2006. Triggers in MS-SQLServer SyntaxTriggers in MS-SQLServer Syntax create trigger overdraft-trigger on account for update as if inserted.balance < 0 begin insert into borrower (select customer-name,account-number from depositor, inserted where inserted.account-number = depositor.account-number) insert into loan values (inserted.account-number, inserted.branch-name, – inserted.balance) update account set balance = 0 from account, inserted where account.account-number = inserted.account-number end
31.
©Silberschatz, Korth and
Sudarshan8.31atabase System Concepts - 5th Edition, Oct 23, 2006. When Not To Use TriggersWhen Not To Use Triggers Triggers were used earlier for tasks such as maintaining summary data (e.g. total salary of each department) Replicating databases by recording changes to special relations (called change or delta relations) and having a separate process that applies the changes over to a replica There are better ways of doing these now: Databases today provide built in materialized view facilities to maintain summary data Databases provide built-in support for replication Encapsulation facilities can be used instead of triggers in many cases Define methods to update fields Carry out actions as part of the update methods instead of through a trigger
32.
©Silberschatz, Korth and
Sudarshan8.32atabase System Concepts - 5th Edition, Oct 23, 2006. Authorization in SQLAuthorization in SQL (see also Section(see also Section 4.3)4.3) Forms of authorization on parts of the database: Read authorization - allows reading, but not modification of data. Insert authorization - allows insertion of new data, but not modification of existing data. Update authorization - allows modification, but not deletion of data. Delete authorization - allows deletion of data
33.
©Silberschatz, Korth and
Sudarshan8.33atabase System Concepts - 5th Edition, Oct 23, 2006. Authorization (Cont.)Authorization (Cont.) Forms of authorization to modify the database schema: Index authorization - allows creation and deletion of indices. Resources authorization - allows creation of new relations. Alteration authorization - allows addition or deletion of attributes in a relation. Drop authorization - allows deletion of relations.
34.
©Silberschatz, Korth and
Sudarshan8.34atabase System Concepts - 5th Edition, Oct 23, 2006. Authorization and ViewsAuthorization and Views Users can be given authorization on views, without being given any authorization on the relations used in the view definition Ability of views to hide data serves both to simplify usage of the system and to enhance security by allowing users access only to data they need for their job A combination or relational-level security and view-level security can be used to limit a user’s access to precisely the data that user needs.
35.
©Silberschatz, Korth and
Sudarshan8.35atabase System Concepts - 5th Edition, Oct 23, 2006. View ExampleView Example Suppose a bank clerk needs to know the names of the customers of each branch, but is not authorized to see specific loan information. Approach: Deny direct access to the loan relation, but grant access to the view cust-loan, which consists only of the names of customers and the branches at which they have a loan. The cust-loan view is defined in SQL as follows: create view cust-loan as select branchname, customer-name from borrower, loan where borrower.loan-number = loan.loan-number
36.
©Silberschatz, Korth and
Sudarshan8.36atabase System Concepts - 5th Edition, Oct 23, 2006. View Example (Cont.)View Example (Cont.) The clerk is authorized to see the result of the query: select * from cust-loan When the query processor translates the result into a query on the actual relations in the database, we obtain a query on borrower and loan. Authorization must be checked on the clerk’s query before query processing replaces a view by the definition of the view.
37.
©Silberschatz, Korth and
Sudarshan8.37atabase System Concepts - 5th Edition, Oct 23, 2006. Authorization on ViewsAuthorization on Views Creation of view does not require resources authorization since no real relation is being created The creator of a view gets only those privileges that provide no additional authorization beyond that he already had. E.g. if creator of view cust-loan had only read authorization on borrower and loan, he gets only read authorization on cust-loan
38.
©Silberschatz, Korth and
Sudarshan8.38atabase System Concepts - 5th Edition, Oct 23, 2006. Granting of PrivilegesGranting of Privileges The passage of authorization from one user to another may be represented by an authorization graph. The nodes of this graph are the users. The root of the graph is the database administrator. Consider graph for update authorization on loan. An edge Ui → Uj indicates that user Ui has granted update authorization on loan to Uj.
39.
©Silberschatz, Korth and
Sudarshan8.39atabase System Concepts - 5th Edition, Oct 23, 2006. Authorization Grant GraphAuthorization Grant Graph Requirement: All edges in an authorization graph must be part of some path originating with the database administrator If DBA revokes grant from U1: Grant must be revoked from U4 since U1 no longer has authorization Grant must not be revoked from U5 since U5 has another authorization path from DBA through U2 Must prevent cycles of grants with no path from the root: DBA grants authorization to U7 U7 grants authorization to U8 U8 grants authorization to U7 DBA revokes authorization from U7 Must revoke grant U7 to U8 and from U8 to U7 since there is no path from DBA to U7 or to U8 anymore.
40.
©Silberschatz, Korth and
Sudarshan8.40atabase System Concepts - 5th Edition, Oct 23, 2006. Security Specification in SQLSecurity Specification in SQL The grant statement is used to confer authorization grant <privilege list> on <relation name or view name> to <user list> <user list> is: a user-id public, which allows all valid users the privilege granted A role (more on this later) Granting a privilege on a view does not imply granting any privileges on the underlying relations. The grantor of the privilege must already hold the privilege on the specified item (or be the database administrator).
41.
©Silberschatz, Korth and
Sudarshan8.41atabase System Concepts - 5th Edition, Oct 23, 2006. Privileges in SQLPrivileges in SQL select: allows read access to relation,or the ability to query using the view Example: grant users U1, U2, and U3 select authorization on the branch relation: grant select on branch to U1, U2, U3 insert: the ability to insert tuples update: the ability to update using the SQL update statement delete: the ability to delete tuples. references: ability to declare foreign keys when creating relations. usage: In SQL-92; authorizes a user to use a specified domain all privileges: used as a short form for all the allowable privileges
42.
©Silberschatz, Korth and
Sudarshan8.42atabase System Concepts - 5th Edition, Oct 23, 2006. Privilege To Grant PrivilegesPrivilege To Grant Privileges with grant option: allows a user who is granted a privilege to pass the privilege on to other users. Example: grant select on branch to U1 with grant option gives U1 the select privileges on branch and allows U1 to grant this privilege to others
43.
©Silberschatz, Korth and
Sudarshan8.43atabase System Concepts - 5th Edition, Oct 23, 2006. RolesRoles Roles permit common privileges for a class of users can be specified just once by creating a corresponding “role” Privileges can be granted to or revoked from roles, just like user Roles can be assigned to users, and even to other roles SQL:1999 supports roles create role teller create role manager grant select on branch to teller grant update (balance) on account to teller grant all privileges on account to manager grant teller to manager grant teller to alice, bob grant manager to avi
44.
©Silberschatz, Korth and
Sudarshan8.44atabase System Concepts - 5th Edition, Oct 23, 2006. Revoking Authorization in SQLRevoking Authorization in SQL The revoke statement is used to revoke authorization. revoke<privilege list> on <relation name or view name> from <user list> [restrict| cascade] Example: revoke select on branch from U1, U2, U3 cascade Revocation of a privilege from a user may cause other users also to lose that privilege; referred to as cascading of the revoke. We can prevent cascading by specifying restrict: revoke select on branch from U1, U2, U3 restrict With restrict, the revoke command fails if cascading revokes are required.
45.
©Silberschatz, Korth and
Sudarshan8.45atabase System Concepts - 5th Edition, Oct 23, 2006. Revoking Authorization in SQLRevoking Authorization in SQL (Cont.)(Cont.) <privilege-list> may be all to revoke all privileges the revokee may hold. If <revokee-list> includes public all users lose the privilege except those granted it explicitly. If the same privilege was granted twice to the same user by different grantees, the user may retain the privilege after the revocation. All privileges that depend on the privilege being revoked are also revoked.
46.
©Silberschatz, Korth and
Sudarshan8.46atabase System Concepts - 5th Edition, Oct 23, 2006. Limitations of SQL AuthorizationLimitations of SQL Authorization SQL does not support authorization at a tuple level E.g. we cannot restrict students to see only (the tuples storing) their own grades With the growth in Web access to databases, database accesses come primarily from application servers. End users don't have database user ids, they are all mapped to the same database user id All end-users of an application (such as a web application) may be mapped to a single database user The task of authorization in above cases falls on the application program, with no support from SQL Benefit: fine grained authorizations, such as to individual tuples, can be implemented by the application. Drawback: Authorization must be done in application code, and may be dispersed all over an application Checking for absence of authorization loopholes becomes very difficult since it requires reading large amounts of application code
47.
©Silberschatz, Korth and
Sudarshan8.47atabase System Concepts - 5th Edition, Oct 23, 2006. Audit TrailsAudit Trails An audit trail is a log of all changes (inserts/deletes/updates) to the database along with information such as which user performed the change, and when the change was performed. Used to track erroneous/fraudulent updates. Can be implemented using triggers, but many database systems provide direct support.
48.
©Silberschatz, Korth and
Sudarshan8.48atabase System Concepts - 5th Edition, Oct 23, 2006. Application SecurityApplication Security Data may be encrypted when database authorization provisions do not offer sufficient protection. Properties of good encryption technique: Relatively simple for authorized users to encrypt and decrypt data. Encryption scheme depends not on the secrecy of the algorithm but on the secrecy of a parameter of the algorithm called the encryption key. Extremely difficult for an intruder to determine the encryption key.
49.
©Silberschatz, Korth and
Sudarshan8.49atabase System Concepts - 5th Edition, Oct 23, 2006. Encryption (Cont.)Encryption (Cont.) Data Encryption Standard (DES) substitutes characters and rearranges their order on the basis of an encryption key which is provided to authorized users via a secure mechanism. Scheme is no more secure than the key transmission mechanism since the key has to be shared. Advanced Encryption Standard (AES) is a new standard replacing DES, and is based on the Rijndael algorithm, but is also dependent on shared secret keys Public-key encryption is based on each user having two keys: public key – publicly published key used to encrypt data, but cannot be used to decrypt data private key -- key known only to individual user, and used to decrypt data. Need not be transmitted to the site doing encryption. Encryption scheme is such that it is impossible or extremely hard to decrypt data given only the public key. The RSA public-key encryption scheme is based on the hardness of factoring a very large number (100's of digits) into its prime components.
50.
©Silberschatz, Korth and
Sudarshan8.50atabase System Concepts - 5th Edition, Oct 23, 2006. AuthenticationAuthentication Password based authentication is widely used, but is susceptible to sniffing on a network Challenge-response systems avoid transmission of passwords DB sends a (randomly generated) challenge string to user User encrypts string and returns result. DB verifies identity by decrypting result Can use public-key encryption system by DB sending a message encrypted using user’s public key, and user decrypting and sending the message back Digital signatures are used to verify authenticity of data E.g. use private key (in reverse) to encrypt data, and anyone can verify authenticity by using public key (in reverse) to decrypt data. Only holder of private key could have created the encrypted data. Digital signatures also help ensure nonrepudiation: sender cannot later claim to have not created the data
51.
©Silberschatz, Korth and
Sudarshan8.51atabase System Concepts - 5th Edition, Oct 23, 2006. Digital CertificatesDigital Certificates Digital certificates are used to verify authenticity of public keys. Problem: when you communicate with a web site, how do you know if you are talking with the genuine web site or an imposter? Solution: use the public key of the web site Problem: how to verify if the public key itself is genuine? Solution: Every client (e.g. browser) has public keys of a few root-level certification authorities A site can get its name/URL and public key signed by a certification authority: signed document is called a certificate Client can use public key of certification authority to verify certificate Multiple levels of certification authorities can exist. Each certification authority presents its own public-key certificate signed by a higher level authority, and Uses its private key to sign the certificate of other web sites/authorities
52.
Database System Concepts ©Silberschatz,
Korth and Sudarshan See www.db-book.com for conditions on re-use ©Silberschatz, Korth and SudarshanDatabase System Concepts End of ChapterEnd of Chapter
Download now