In this article, we will learn some of the core components of JDBC

 

JDBC Core components

• DriverManager
• Driver
• Connection
• Statement
• ResultSet

 

1. DriverManager

• DriverManager is a mean through which it connects to databases using appropriate driver supplied from Java application
• DriverManager registers all driver requests comes from Java application and picks up appropriate driver to connect to database

  public static void registerDriver(Driver driver);
  

• DriverManager has number of useful static methods to get connection objects, these are

  public static Connection getConnection(String dbUrl);
  
  public static Connection getConnection(String dbUrl, 
  		String username,String password);
  
  public static Connection getConnection(String dbUrl, 
  		Properties props);
  

 

2. JDBC Driver

• Drivers are the one which actually communicates with the databases
• But user generally never interact with drivers directly
• Instead, user go through DriverManager to register and de-register drivers and then communicate with database

 

3. Connection

• After registering drivers, DriverManager has got number of static getConnection() method to return Connection object
• It is only after successfully getting connection object, user can interact with database
• Connection interface also got some useful methods like setAutoCommit(boolean), commit(), rollback() methods to handle transaction
• Using connection object, we can create/prepare all three types of statements i.e.;

  createStatement(); // for Statement
  prepareStatement(); // for PreparedStatement
  prepareCall(); // for CallableStatement
  

 

4. Statement

• Statement interface is the one which is actually used to execute queries like inserting new record or updating an existing record
• executeQuery(String sqlQuery); and executeUpdate(String sqlQuery) are the most commonly used methods from Statement interface
• executeQuery(String sqlQuery); returns object of ResultSet
• There is also executeBatch(); method for batch execution

 

5. ResultSet

• ResultSet holds data retrieved from database when performing/executing queries (both SQL and MySQL)
• You can traverse in ResultSet to read data one-by-one, but in forward direction only
• But by setting static variable “TYPE_SCROLL_INSENSITIVE” in createStatement(), we can make it scrollable in both directions
• Similarly, by setting static variable “CONCUR_UPDATABLE” in createStatement(), we can make ResultSet updatable, as it is not updatable by default

 

Read Also:

• JDBC Tutorial index
• Introduction to JDBC
• Different types of JDBC drivers
• JDBC Driver list for all leading databases
• JDBC connection steps
• MySQL database connection steps
• Oracle database connection steps
• MS Access database connection steps

 

References:

• https://docs.oracle.com/javase/tutorial/jdbc/basics/gettingstarted.html
• https://docs.oracle.com/cd/E11882_01/java.112/e16548/overvw.htm#JJDBC28025
• http://docs.oracle.com/javase/tutorial/jdbc/basics/index.html
• https://en.wikipedia.org/wiki/JDBC_driver
• http://www.devx.com/tips/Tip/28818
• https://docs.oracle.com/javase/7/docs/api/java/lang/Class.html#forName(java.lang.String)

 

Happy Coding !!
Happy Learning !!