Getting Startedwith pureQuery

246
Getting Started with pureQuery
format specified by the name and parameters of the method. When you call a getXXX
method and there is no next (or first) query result, the method closes the
StoredProcedureResult object and returns null.
The query result formats that the getXXX methods in the StoredProcedureResult
interface provide are very similar to the query result formats that the queryXXX methods of
the com.ibm.pdq.runtime.Data interface provide. Use the following questions as a
guide to help you select the right return type:
• What format do you want to use for each row?
o
o
o
A pureQuery bean or a scalar object: getXXX methods that have
a parameter Class returnClass store the contents of
each row in an instance of returnClass.
• If returnClass is a pureQuery bean, pureQuery
creates an instance of returnClass and sets the
values of its properties according to the values of the
columns returned from the database. pureQuery uses
the rules defined in Section 3.3.1 to determine the bean
property that represents each column that is selected
from the database. When pureQuery cannot find a
property that represents a column in the SQL statement,
pureQuery does not store the value of that column in the
bean.
• If returnClass is not a pureQuery bean, pureQuery
constructs an object of type returnClass and attempts
to store the contents of the first column of the query
result in that object.
An object of a specific type, constructed by a
RowHandler object: getXXX methods that have a
parameter RowHandler rowHandler use rowHandler
to create the object that contains each row.
A java.util.Map object: queryXXX
methods that do not have a parameter Class
returnClass or a parameter RowHandler
rowHandler return the contents of each row in a
Map object, in which the keys are the column
labels, and the values are the contents of the columns.
• What object do you want to use to contain all of the rows?
o
An array: getArray methods return an array in which each entry
represents a row.