Working with mapped statements - iBATIS in Action - page 88

Table 4.3 Mapped statement types and related XML elements (continued)

Statement type Attributes Child elements Uses More details

<statement> id

parameterClass
resultClass
parameterMap
resultMap
cacheModel
xmlResultName

All dynamic elements Catching all statement

types that can be used to
execute nearly anything

Section
6.3.1;
chapter 8

<sql> id All dynamic elements Not really a mapped

statement, but used to
make components that
can be used in mapped
statements

Section 4.2;
chapter 8

<include> refid None Not really a mapped

statement, but used to
insert components cre-
ated with the <sql> type
into mapped statements

Section 4.2

In this chapter, we focus on the <select> mapped statement type. In addition to
the mapped statement types, two additional elements are included in table 4.3
that are commonly used to build mapped statements: the <sql> element and the
<include> element. These elements work together to create and insert compo-
nents into mapped statements. You will find them useful when you have complex
SQL fragments that you want to be able to reuse without duplicating them.
The <sql> element is used to create text fragments that can be grouped
together to create complete SQL statements. For example, you may have a query
with a complex set of conditions for the WHERE section. If you need to select a
record count using the same complex set of conditions but do not want to dupli-
cate them, you can put them into a <sql> fragment and include them in the query
that does the count, as well as in the query that returns the actual data. Listing 4.1
contains a simple example.

Listing 4.1 An example of the <sql> and <include> tags

B Gets all columns

<sql id="select-order">
select * from order
</sql>

C Gets count

<sql id="select-count">
select count(*) as value from order