IBatisNet 之 自动生成主关键字
很多系统支持自动生成主关键字。一些数据库厂商预先生成(oracle)，一些数据库厂商之后生成(mssal mysql).。如果你在<insert>元素中使用<selectKey>节，你就能获得一个预先生成的key.。下面的例子演示了这种方法：
<!—Oracle SEQUENCE Example --> <insert id="insertProduct-ORACLE" parameterClass="product"> <selectKey resultClass="int" Property="id" > SELECT STOCKIDSEQUENCE.NEXTVAL AS ID FROM DUAL </selectKey> insert into PRODUCT (PRD_ID,PRD_DESCRIPTION) values (#id#,#description#) </insert> <!— Microsoft SQL Server IDENTITY Column Example --> <insert id="insertProduct-MS-SQL" parameterClass="product"> insert into PRODUCT (PRD_DESCRIPTION) values (#description#) <selectKey resultClass="int" Property="id" > SELECT @@IDENTITY AS ID </selectKey> </insert> |
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上面是IbatisNet的iBATIS Data Mapper Developer Guide上的说明：下面来介绍一下具体的应用和注意的地方： person.xml
?xml version="1.0" encoding="utf-8" ?>
<sqlMap
namespace="Person"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:noNamespaceSchemaLocation="SqlMap.xsd">
<!-- XML "behind" document for the People service class. -->
<alias>
<typeAlias alias="Person" type="IbatisTest.Domain.Person, IbatisTest.Domain" />
</alias>
<resultMaps>
<resultMap id="SelectResult" class="Person">
<result property="Id" column="PER_ID" />
<result property="FirstName" column="PER_FIRST_NAME" />
<result property="LastName" column="PER_LAST_NAME" />
<result property="BirthDate" column="PER_BIRTH_DATE" />
<result property="WeightInKilograms" column="PER_WEIGHT_KG" />
<result property="HeightInMeters" column="PER_HEIGHT_M" />
</resultMap>
</resultMaps>
<insert id="Insert" parameterClass="Person">
insert into PERSON
(PER_FIRST_NAME, PER_LAST_NAME,
PER_BIRTH_DATE, PER_WEIGHT_KG, PER_HEIGHT_M)
values
( #FirstName#, #LastName#,
#BirthDate#, #WeightInKilograms#, #HeightInMeters#)
<selectKey property="Id" type="post" resultClass="int">
select CAST(@@IDENTITY as int) as value
</selectKey>
</insert>
</statements>
</sqlMap>
<selectKey>节返回一个从sql server生成的自动生成关键字。
//新增一个员工
private void Button1_Click(object sender, System.EventArgs e)
{
IbatisTest.Domain.Person person = new IbatisTest.Domain.Person();
person.Id =-1;//这里的赋值很重要，否则会出错
person.FirstName = "--New Person--";
person.BirthDate = Convert.ToDateTime("2000-4-2");
PersonHelper personhelper = new PersonHelper();
personhelper.Insert(person);
}
//业务逻辑类方法
public int Insert (Person person)
{
try
{
int result = -1;
result =(int)Mapper().Insert("Insert",person);
return result;
}
catch(Exception ex)
{
throw ex;
}
}