Introduction to JDBC - Java Database Programming Bible - page 136

Table 4-3: ResultSet getter Methods

Data Type Method

boolean getBoolean(String columnName)

byte getByte(String columnName)

byte[] getBytes(String columnName)

double getDouble(String columnName)

float getFloat(String columnName)

int getInt(String columnName)

java.io.InputStream getAsciiStream(String columnName)

java.io.InputStream getUnicodeStream(String columnName)

java.io.InputStream getBinaryStream(String columnName)

java.sql.Date getDate(String columnName)

java.sql.Time getTime(String columnName)

java.sql.Timestamp getTimestamp(String columnName)

long getLong(String columnName)

Object getObject(String columnName)

short getShort(String columnName)

String getString(String columnName)

Data can be retrieved using either the column name or the column number. For
example, the previous example uses column names. However, you can get the same
results using column numbers, assuming you know what they are. Here's an
example:

ResultSet rs = stmt.executeQuery("SELECT First_Name, Last_Name FROM Customers");
while (rs.next()){
System.out.println(rs.getString(2)+•, •+rs.getString(1));
}

The option of using column names is provided so that if you specify column names in
a query, you can use the same names as the arguments to getter methods.

A problem that can arise using column names is that if you do a join on two tables, it
is possible for a SQL query to return a result set that has more than one column with
the same name. If you then use the column name as the parameter to a getter
method, it will return the value of the first matching column name.