Oracle Programming

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Oracle Programming
2
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
  oraclethin_at_cci-ora02.uncc.edu1521class,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/tutor
  ial/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.edu8080/wwang22/HelloW
  orld
• HelloWorld.java on the class webpage
• More examples
• DBServlet
• http//coit-servlet02.uncc.edu8080/wwang22/DBServ
  let.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.