Can you explain how the ResultSet object is implemented and how it functions to retrieve data from the database?

ResultSet in Java is an interface that represents a table of data obtained as a result of executing an SQL query via JDBC.

How it works:

• After executing a query through a Statement or PreparedStatement object, the executeQuery() method is called, which returns a ResultSet.
• ResultSet contains a cursor that initially points before the first row of the result.
• To iterate over the data, the next() method is used, which moves the cursor to the next row and returns true if the row exists.
• To retrieve values from the current row, methods like getString(), getInt(), getDate(), etc., are used, specifying the column name or index.

Example:

ResultSet rs = statement.executeQuery("SELECT id, name FROM users");
while (rs.next()) {
    int id = rs.getInt("id");
    String name = rs.getString("name");
    // process data
}

Thus, ResultSet provides sequential access to the rows of the SQL query result and allows extracting data by columns.