Java – Core JDBC components

May 26, 2016 SJ JDBC 0

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

JDBC Core components :

  1. DriverManager
  2. Driver
  3. Connection
  4. Statement
  5. 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

Related Articles :

References :

Happy Coding !!
Happy Learning !!

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Java – JDBC Driver list for all leading database

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