Getting Startedwith pureQuery

Chapter 14 – Best Practices 283
@Select(sql="SELECT PROJECT.PROJNO, DEPARTMENT.DEPTNO " +
"FROM PROJECT, DEPARTMENT " +
"WHERE PROJECT.DEPTNO =
DEPARTMENT.DEPTNO")
List getProjectsDepartment();
Listing 14.3 – Returning a types list of beans
Using table collation to aggregate results form multiple tables leverages the table-to-bean
mapping provided by pureQuery and prevents you from having to design complex beans
that would store the result of the join SQL statement.
14.4 Working with Exception categorization
When pureQuery executes JDBC calls, it encapsulates any generated exception into
unchecked exceptions, so that you don’t have to enclose all your pureQuery method calls
in try/catch blocks. By using this process, pureQuery is also able to provide you with
extended metadata about the generated exception when it encapsulates the base JDBC or
SQL exception in a pureQuery DataRuntimeException. This metadata provides you with
the version of pureQuery you are using, the associated SQL state and error code of the
generated exception and also exception categorization information. pureQuery is
aggregating errors and their causes into categories that let you better handle and recover
from the error situation. Some example categories used by pureQuery are
AUTHORIZATION_ERROR, CONSTRAINT_VIOLATION,
DUPLICATE_ROW_VIOLATION, SYNTAX_ERROR, amongst others. For a complete list
of all possible error types, please refer to the pureQuery documentation.
When developing your application, it is recommended that you use these error types as a
strategy for error handling and recovery, as it eliminates the need to handle individual error
types for each pureQuery method call.
14.5 Customizing the code generation templates
pureQuery code generation tooling is based on JET (Java Emitter Templates), a generic
template engine built into Eclipse that can be used to express code you want to generate.
When you use the tooling to generate pureQuery code, there are templates for all the
generated Java class files, as the bean representing the database table, the inline and
annotated method style sample classes and even the JUnit test cases.
ODS allows you to override the existing templates, to write customized code that you wish
to have added automatically to each one of the generated classes. This code can be as
simple as a copyright statement, or more complex like adding some setup code to the
generated test cases. See the official pureQuery documentation for more information
about creating Eclipse Modeling Framework Technologies (EMFT) Java Emitter Templates
(JET) to generate customized code.