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Java

JDBC Part I. Java. JDBC?. Java Database Connectivity JDBC is an API for the Java programming language that defines how a client may access a database It provides methods for querying and updating data in a database JDBC is oriented towards relational databases. Java Database Drivers.

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Java

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  1. JDBC Part I Java

  2. JDBC? • Java Database Connectivity • JDBC is an API for the Java programming language that defines how a client may access a database • It provides methods for querying and updating data in a database • JDBC is oriented towards relational databases

  3. Java Database Drivers • In order to work with relational tables, the program must establish a communication link to the relational database that contains these tables • A database driver provides this link • We are going to use the JDBC Thin Driver

  4. Connecting to a Database First line: import java.sql.*; // in Main method try { Connection conn = DriverManager.getConnection( "jdbc:oracle:thin:@classdb.jccc.edu:1521/cs260", “username", “xxxx"); System.out.println(“connected!”); …. } catch(Exception e) { e.printStackTrace(); } • Open Eclipse and follow along…. • Need to include ojdbc6.zip in Java build path

  5. Using JDBC • Remember in SQL, our select statements returned a result table (aka result set) • We will use the same approach within our Java program • We will create and execute SQL • We will capture the results of the SQL execution within a result set (i.e. an object)

  6. Creating a Result Set Statement statement = conn.createStatement ( ); ResultSet rs = statement.executeQuery ( “Select course_no From student.course” ); Look at this statement, what does it do? Look at this statement, what does it do?

  7. How to move a cursor through a Result Set What is a cursor? while ( rs.next ( ) ) { // code that processes each record of the result set } How does this while loop work?

  8. How to return data from a Result Set Using column names: while ( rs.next ( ) ) { int courseNo = rs.getInt(“Course_No”); System.out.println(“CNo: “ + courseNo); } Explain the above code Using column indexes: while ( rs.next ( ) ) { int courseNo = rs.getInt(1); System.out.println(“CNo: “ + courseNo); } Explain the above code Pick one approach and implement it within your program. Try it.

  9. Practice • Implement both column index and column name code. Run it. What happened and why? • Using either column index or column name, display the number of records you processed • Display the course number and description

  10. For April 21st • Continue with JDBC • Quiz • Project #14 due

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