1. Registering a Driver
    -statically load driver
         Class.forName(“foo.bar.MyDriver”);
         Connection c = DriverManager.getConnection(...);

    -or use the jdbc.drivers system property

2. JDBC URLs
    -jdbc:subprotocol:source
    each driver has its own subprotocol and each subprotocol has its own syntax



3. DriverManager
    Connects to given JDBC URL with given user name and password
    Throws java.sql.SQLException
    returns a Connection object

Connection
1. A Connection represents a session with a specific database.
2. Within the context of a Connection, SQL statements are executed and results are returned.
3. Can have multiple connections to a database
    NB: Some drivers don’t support serialized connections
    Fortunately, most do (now)
4. Also provides “metadata” -- information about the database, tables, and fields
5. Also methods to deal with transactions

Obtaining a Connection
String url   = "jdbc:odbc:mydsn";
try {
    Class.forName ("sun.jdbc.odbc.JdbcOdbcDriver");
    Connection con = DriverManager.getConnection(url);
}
catch (ClassNotFoundException e)
    { e.printStackTrace(); }
catch (SQLException e)
    { e.printStackTrace(); }

Connection Methods
  -Statement createStatement()
    returns a new Statement object
  -PreparedStatement prepareStatement(String sql)
   returns a new PreparedStatement object
  -CallableStatement prepareCall(String sql)
    returns a new CallableStatement object

1. Statement
A Statement object is used for executing a static SQL statement and obtaining the results produced by it.

Statement Methods

ResultSet executeQuery(String)
Execute a SQL statement that returns a single ResultSet.
int executeUpdate(String)
Execute a SQL INSERT, UPDATE or DELETE statement. Returns the number of rows changed.
boolean execute(String)
Execute a SQL statement that may return multiple results.

2. The PreparedStatement Interface

• The prepareStatement() method of Connection interface returns a PreparedStatement object
• Useful for frequently executed SQL statements
• An SQL statement is pre-compiled and gets executed more efficiently than a plain statement

   For example: the statement “INSERT INTO Table1 VALUES (?, ?)” can be used to add multiple records, with a different values each time. Where ‘?’ acts as a placeholder



3. The CallableStatement Interface

• A CallableStatement object is created by calling the prepareCall() method on a Connection object
• The object provides a way to call stored procedures in a standard way for all DBMS
• CallableStatement inherits Statement methods, which deal with SQL statements in general, and it also inherits PreparedStatement methods, which deal with IN parameters
• All methods defined in the CallableStatement deal with OUT parameters or the output aspect of INOUT parameters
• Syntax for a stored procedure without parameters is:
   {call procedure_name}
• Syntax for procedure call with two parameters:
   {call procedure_name[(?, ?)] }