Writing MySQL-Based Programs - MySQL - page 78

++ count ;
}
rs . close (); // close result set
s . close (); // close statement
System . out . println ( "Number of rows returned: " + count );
The ResultSet object returned by the getResultSet() method of your Statement
object has its own methods, such as next() to fetch rows and various get XXX () methods
that access columns of the current row. Initially, the result set is positioned just before
the first row of the set. Call next() to fetch each row in succession until it returns false.
To determine the number of rows in a result set, count them yourself, as shown in the
preceding example.
To access column values, use methods such as getInt() , getString() , getFloat() ,
and getDate() . To obtain the column value as a generic object, use getObject() . The
argument to a get XXX () call can indicate either column position (beginning at 1, not 0)
or column name. The previous example shows how to retrieve the id , name , and cats
columns by position. To access columns by name instead, write the row-fetching loop
as follows:
while ( rs . next ()) // loop through rows of result set
{
int id = rs . getInt ( "id" );
String name = rs . getString ( "name" );
int cats = rs . getInt ( "cats" );
System . out . println ( "id: " + id
+ ", name: " + name
+ ", cats: " + cats );
++ count ;
}
To retrieve a given column value, use any get XXX () call that makes sense for the data
type. For example, getString() retrieves any column value as a string:
String id = rs . getString ( "id" );
String name = rs . getString ( "name" );
String cats = rs . getString ( "cats" );
System . out . println ( "id: " + id
+ ", name: " + name
+ ", cats: " + cats );
Or use getObject() to retrieve values as generic objects and convert the values as nec‐
essary. The following example uses toString() to convert object values to printable
form:
Object id = rs . getObject ( "id" );
Object name = rs . getObject ( "name" );
Object cats = rs . getObject ( "cats" );
System . out . println ( "id: " + id . toString ()
+ ", name: " + name . toString ()
+ ", cats: " + cats . toString ());