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Oracle Programming

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architecture

 

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JDBC (Java Database Connectivity )

JDBC enables programmers to use SQL queries from within java programs to access databases.

JDBC provides transparent access to relational databases from different vendors.

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JDBC

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JDBC steps

Create the database in your dbms Register the database as a data source Import java.sql.* at the beginning of your java file. Connect to a JDBC source

– Connection con = DriverManager.getConnection(“jdbc:oracle:thin:@cci-ora02.uncc.edu:1521:class”,”user”,”passwd”)

Create an SQL statement– Statement stmt = con.createStatement();– stmt.executeUpdate("INSERT INTO sailor

VALUES(22,'dustin',7,45.0)");

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JDBC Step

Execute the statement– ResultSet rs = stmt.executeQuery(“Select * from …”)

Parse the result– rs.next(), rs.getFloat– ResultSetMetaData contains the information about

column Close the statement and connection

– stmt.close()– con.close

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Useful resources

JDBC tutorial http://java.sun.com/docs/books/tutorial/jdbc/index.html

UNCC COIT

https://cci-wiki01.uncc.edu/servlets

SampleJDBC.java on the class webpage

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Java Servlets

Web servers understand requests for pages in http and return their response in HTML format

Static html vs. dynamic html– The webpage is based on data submitted by the user– The data changes frequently (a weather-report)– Web pages uses information from a database(stock)– Maintain separate data about each client for

personalization purposes(cookies). Java servlets are programs that extend the

functionality of a web server and useful for building dynamic web pages on the fly.

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Java Servlet Advantage

Works as a lightweight thread directly with the JVM rather than create a new process

Load once to memory and used by all threads

Share data among each other

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How to run servlets

Your machine, Java servlet development kit(JSDK)

COIT– consult the webpage https://cci-wiki01.uncc.edu/servlets

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Examples

HelloWorld – http://coit-servlet02.uncc.edu:8080/wwang22/HelloWorld

– HelloWorld.java on the class webpage More examples

– DBServlet– http://coit-servlet02.uncc.edu:8080/wwang22/

DBServlet.html

– DBServlet.java on the class webpage

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JDBC and Servlet

Summary: 1. Download PUTTY and WinSCP 2. Download HelloWorld, SampleJDBC and DBServlet source code 3. Modify them and upload to your own space 4. Compile and run it

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Some links

https://cci-wiki01.uncc.edu/servlets

JDBC-Servlet.doc on the class webpage

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Summary 3-tire architecture APIs such as JDBC and ODBC introduce a

layer of abstraction between application and DBMS

Choose your language from JSP, Servlet, ASP, VC++, VB.