This document discusses retrieving data from a database using the ResultSet and Statement interfaces in Java. It explains how to use a Statement object to execute a SQL query and retrieve the ResultSet. It also covers using a PreparedStatement object to execute parameterized queries and retrieve the ResultSet. The document provides code examples of retrieving field data from the ResultSet and closing the resources.

1. Retrieving data from
database using ResultSet
Presented by :
Manohar Bhasin, Rishi Singh

2. CONTENT
 Introduction to Statement and ResultSet Interface
 Retrieving data from database using Statement and
ResultSet Interface.
 Retrieving data from database using
PreparedStatement and ResultSet Interface.

3. Statement Interface
The object used for executing a static SQL statement
and returning the results it produces.
public interface Statement extends Wrapper,
AutoCloseable
ResultSet Interface
A ResultSet object maintains a cursor pointing to its
current row of data. Initially the cursor is positioned
before the first row.
public interface ResultSet extends Wrapper,
AutoCloseable

4. Retrieving data from database using Statement
and ResultSet Interface.
String name;
Connection con;
Statement stmt;
ResultSet rs;
…
stmt = con.createStatement();
rs = stmt.executeQuery(“select empname from employee where salary=2000”);
while(rs.next())
{
name=rs.getString(1);
System.out.println(name);
}
rs.close();
stmt.close();

5. stmt = con.createStatement();
Statement createStatement() throws
SQLException
Creates a Statement object for sending SQL statements to the
database.

6. Retrieving data from database using Statement
and ResultSet Interface.
String name
Connection con;
Statement stmt;
ResultSet rs;
…
stmt = con.createStatement();
rs = stmt.executeQuery(“select empname from employee where salary=2000”);
while(rs.next())
{
name=rs.getString(1);
System.out.println(name);
}
rs.close();
Stmt.close();

7. ResultSet executeQuery(String sql) throws SQLException
Executes the given SQL statement, which returns
a ResultSet object.
 rs = stmt.executeQuery(“select empname from employee where
salary=2000”);
stmt = con.createStatement();
Statement createStatement() throws
SQLException
Creates a Statement object for sending SQL statements to the
database.

8. Retrieving data from database using Statement
and ResultSet Interface.
String name
Connection con;
Statement stmt;
ResultSet rs;
…
stmt = con.createStatement();
rs = stmt.executeQuery(“select empname from employee where salary=2000”);
while(rs.next())
{
name=rs.getString(1);
System.out.println(name);
}
rs.close();
stmt.close();

9. Retrieving data from database using
PreparedStatement and ResultSet Interface.
String name
Connection con;
PreparedStatement pstmt;
ResultSet rs;
…
pstmt = con.prepareStatement(“select empname from employee where empid= ?” );
Pstmt.setString(1,empid);
rs = pstmt.executeQuery();
while(rs.next())
{
name=rs.getString(1);
System.out.println(name);
}
rs.close();
Stmt.close();

10. pstmt = con.prepareStatement(“select empname from
employee where empid= ?” );
PreparedStatement prepareStatement(String sql)
throws SQLException
• Creates a PreparedStatement object for sending parameterized
SQL statements to the database.
• This method is optimized for handling parametric SQL
statements that benefit from precompilation.

11. Retrieving data from database using
PreparedStatement and ResultSet Interface.
String name
Connection con;
PreparedStatement pstmt;
ResultSet rs;
…
pstmt = con.prepareStatement(“select empname from employee where empid= ?” );
Pstmt.setString(1,empid);
rs = pstmt.executeQuery();
while(rs.next())
{
name=rs.getString(1);
System.out.println(name);
}
rs.close();
pstmt.close();

12. rs = pstmt.executeQuery();
ResultSet executeQuery() throws SQLException
•Executes the SQL query in the PreparedStatement Object and
returns the ResultSet object generated by the query
•Result sets created using the PreparedStatement object will by
default be type TYPE_FORWARD_ONLY and have concurrency
level of CONCUR_READ_ONLY.

13. Retrieving data from database using
PreparedStatement and ResultSet Interface.
String name
Connection con;
PreparedStatement pstmt;
ResultSet rs;
…
pstmt = con.prepareStatement(“select empname from employee where empid= ?” );
Pstmt.setString(1,empid);
rs = pstmt.executeQuery();
while(rs.next())
{
name=rs.getString(1);
System.out.println(name);
}
rs.close();
pstmt.close();

14. THANK YOU