Getting Startedwith pureQuery

11.4.1 Declaring the return type
Chapter 11 – Annotated-Method Programming Style 217
Use the following questions as a guide to help you select the right return type for your
annotated methods.
11.4.1.1 Methods with the @Select annotation
• What format do you want to use for each row?
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A pureQuery bean or a scalar: pureQuery creates and populates
the object automatically. For pureQuery beans, pureQuery uses
the rules defined in Section 3.31 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. For scalars, pureQuery constructs an object
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
com.ibm.pdq.runtime.handlers.RowHandler
object: You will have to specify the RowHandler that will
construct the object.
A java.util.Map object: pureQuery
constructs a Map in which the keys contain the labels of the
columns and the values contain the contents of the columns.
• What object do you want to contain all of the rows?
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An array in which each entry represents a row: Specify an array
as the return type, such as MyPureQueryBean[].
A java.util.List object in which each element represents a
row: Specify the parameterized List as the return type, such as
java.util.List.
A java.util.Iterator object for which each call to the
Iterator's next() method returns a row. Specify the
parameterized Iterator as the return type, such as
java.util.Iterator. Methods with
this return type do not fully materialize the information from the
database during the initial method call. Instead, pureQuery
retrieves one row each time the application calls the next
method. This is particularly useful if your application retrieves
large amounts of information from the database, and you do not
want to store all of the information in memory at one time. When
the application calls next() to retrieve all of the rows from the