Getting Startedwith pureQuery

Chapter 11 – Annotated-Method Programming Style 209
Figure 11.2 shows the return types that user-defined annotated methods can have.
RowType[]
RowType
Iterator
List
ResultSet
ResultType
Instance of
User-defined interface
User-defined method
@Select(sql=“SELECT …”)
User-defined method
@Update(sql=“INSERT …”)
User-defined method
@Update(sql=“UPDATE …”)
User-defined method
@Update(sql=“DELETE …”)
User-defined method
@Call(sql=“CALL …”)
Update
count
Update
counts
RowType[]
Iterator
List
ResultSet
StoredProcedureResult
CallResultType
Figure 11.2 - The possible return types of user-defined annotated methods
In Figure 11.2, RowType represents the format in which each row of a query result is
returned. There are a number of ways to specify this. ResultType represents the format
that is specified by the parameterized type RES of a
com.ibm.pdq.runtime.handlers.ResultHandler object. CallResultType
represents the format that is specified by the parameterized type CAL of a
com.ibm.pdq.runtime.handlers.CallHandlerWithParameters object.
Chapter 8 discusses pureQuery handlers.
There are several benefits to using the annotated-method programming style. These are
some of them:
• You can speed-up your application development. pureQuery generates
the method implementations. All you have to do is declare methods with
your choice of parameters and return types, and write the SQL statements
for the methods to execute. The tools take care of the rest of the work.
• You can choose from a wide variety of return types for the query results.
A few of the possible formats are a single pureQuery bean, a single
java.util.Map, a collection of pureQuery beans, and a collection of
Maps.
• If you are using the IBM ® DB2 ® Database, you can easily switch between
dynamic and static execution of the SQL. Static SQL has many
performance, reliability, and security advantages. For a brief description
of static SQL see Appendix C.