JDBC.ppt database connectivity in java ppt
- 1. Introduction to JDBC Michelle Lee, Ye Wu & Jeff Offutt http://www.cs.gmu.edu/~offutt/ SWE 432 Design and Implementation of Software for the Web
- 2. 3/19/2024 © Wu, Lee & Offutt 2 JDBC • JDBC (Java Database Connectivity) API allows Java programs to connect to databases • Database access is the same for all database vendors • The JVM uses a JDBC driver to translate generalized JDBC calls into vendor specific database calls • There are four general types of JDBC drivers – We will look at Type 4 …
- 3. 3/19/2024 © Wu, Lee & Offutt 3 Pure Java Driver (Type 4) • These drivers convert the JDBC API calls to direct network calls using vendor-specific networking protocols by making direct socket connections with the database • It is the most efficient method to access database, both in performance and development time • It is the simplest to deploy • All major database vendors provide pure Java JDBC drivers for their databases and they are also available from third party vendors • For a list of JDBC drivers, refer to – http://industry.java.sun.com/products/jdbc/drivers
- 4. 3/19/2024 © Wu, Lee & Offutt 4 Java Application DB Client Pure Java Driver (2) JDBC API JDBC Driver Data Source Server
- 5. 3/19/2024 © Wu, Lee & Offutt 5 Typical JDBC Programming Procedure 1. Load the database driver 2. Obtain a connection 3. Create and execute statements (SQL queries) 4. Use result sets (tables) to navigate through the results 5. Close the connection
- 6. 3/19/2024 © Wu, Lee & Offutt 6 Driver Manager • The purpose of the java.sql.DriverManger class in JDBC is to provide a common access layer on top of different database drivers used in an application • DriverManager requires that each driver required by the application must be registered before use, so that the DriverManager is aware of it • Load the database driver using ClassLoader : – Class.forName (“oracle.jdbc.driver.OracleDriver”);
- 7. 3/19/2024 © Wu, Lee & Offutt 7 Connecting to a Database • Type 4 JDBC Driver – Oracle Server Class.forName (“oracle.jdbc.driver.OracleDriver”); con = DriverManager.getConnection ( “jdbc:oracle:thin:@bonsai.ite.gmu.edu:1521:ite”, “accountname", “password”); • Type 4 JDBC Driver – MySQL Server Class.forName (“org.gjt.mm.mysql.Driver”); con = DriverManager.getConnection (“jdbc:mysql://localhost/databasename”, uid, passwd);
- 8. 3/19/2024 © Wu, Lee & Offutt 8 Creating Tables • Creating a Coffee table CREATE TABLE COFFEES (COF_NAME VARCHAR(32), SUP_ID INTEGER, PRICE FLOAT, SALES INTEGER, TOTAL INTEGER) • Creating JDBC statements Statement stmt = con.createStatement (); • Execute a statement stmt.executeUpdate (“CREATE TABLE COFFEES “ + “(COF_NAME VARCHAR(32), SUP_ID INTEGER, PRICE FLOAT, “ + “SALES INTEGER, TOTAL INTEGER)”); SQL query
- 9. 3/19/2024 © Wu, Lee & Offutt 9 Execute Statements • This uses executeUpdate because the SQL statement contained in createTableCoffees is a DDL (data definition language) statement • Statements that create a table, alter a table, or drop a table are all examples of DDL statements and are executed with the method executeUpdate • executeUpdate is also used to execute SQL statements that update a table
- 10. 3/19/2024 © Wu, Lee & Offutt 10 Execute Statements • In practice, executeUpdate is used far more often to update tables than it is to create them because a table is created once but may be updated many times • The method used most often for executing SQL statements is executeQuery • executeQuery is used to execute SELECT statements, which comprise the vast majority of SQL statements
- 11. 3/19/2024 © Wu, Lee & Offutt 11 Entering Data into a Table Statement stmt = con.createStatement(); stmt.executeUpdate ( "INSERT INTO COFFEES " + "VALUES ('Colombian', 101, 7.99, 0, 0)"); stmt.executeUpdate ( "INSERT INTO COFFEES " + "VALUES ('French_Roast', 49, 8.99, 0, 0)" ); stmt.executeUpdate ( "INSERT INTO COFFEES " + "VALUES ('Espresso', 150, 9.99, 0, 0)" ); stmt.executeUpdate ( "INSERT INTO COFFEES " + "VALUES ('Colombian_Decaf', 101, 8.99, 0, 0)" ); stmt.executeUpdate ( "INSERT INTO COFFEES " + "VALUES ('French_Roast_Decaf', 49, 9.99, 0, 0)" );
- 12. 3/19/2024 © Wu, Lee & Offutt 12 Getting Data From a Table ResultSet rs = stmt.executeQuery ("SELECT COF_NAME, PRICE FROM COFFEES"); while (rs.next()) { String s = rs.getString ("COF_NAME"); float n = rs.getFloat ("PRICE"); System.out.println (s + " " + n); }
- 13. 3/19/2024 © Wu, Lee & Offutt 13 JNDI Connection Manager JDBC Data Source Architecture Application JDBC Database
- 14. 3/19/2024 © Wu, Lee & Offutt 14 Sample code • Sun JDBC tutorial