iBATIS data access objects - iBATIS in Action - page 239

<select id="getMapListByExample" resultClass="hashmap">
<include refid="getByExample" />
</select>

Mapped statement
for a map

F

<select id="getIdDescriptionListByExample"
resultClass="IdDescription">
select
accountId as id,
COALESCE(firstname, '(no first name)')
|| ' '
|| COALESCE(lastname, '(no last name)')
as description
from Account
<include refid="whereByExample" />
</select>

Mapped statement
for a name/value list

G

<select id="getById" resultClass="Account">
select
<include refid="allFields" />
from Account
where accountId = #value#
</select>

</sqlMap>

b

In this SQL map, we define a SQL fragment that list all of our fields. In this case,
the driver we are using messes with the case of the columns, so we used explicit col-
umn aliases to make sure they were right for our implicit property mapping.
Another SQL fragment is used to define a complex WHERE clause that we will use.
A third SQL fragment is used to pull the other two into a single fragment that we
then use in two select statements—one to get a List of beans

C
D

E

and another to get

F G

a List of Maps . In the getIdDescriptionListByExample mapped statement , we

use the complex WHERE clause again to get a List of a different type of beans.

10.4.5 Coding the DAO implementation

Finally, we get to the actual DAO implementation. As we mentioned before, to cre-
ate a DAO , we provide both an interface and an implementation. In this case, the
interface is defined as com.mycompany.system.dao.AccountDao , and the imple-
mentation is defined as com.mycompany.system.dao.sqlmap.AccountDaoImpl .
We saw the interface in section 10.3, so we will not repeat it here, but we will
take a look at the DAO implementation class (see listing 10.11).