iBatis自动生成的主键 (Oracle,MS Sql Server,MySQL)
转载
iBatis的sqlMap配置文件的
selectKey元素有个
type属性,可以指定
pre或者
post表示前生成(
pre)还是后生成(
post)。
Oracle设置
Xml代码
1. <!-- Oracle SEQUENCE -->
2. <insertid="insertProduct-ORACLE"parameterClass="com.domain.Product">
3. <selectKeyresultClass="int"keyProperty="id"type="pre">
4. <![CDATA[SELECT STOCKIDSEQUENCE.NEXTVAL AS ID FROM DUAL]]>
5. </selectKey>
6. <![CDATA[insert into PRODUCT (PRD_ID,PRD_DESCRIPTION) values(#id#,#description#)]]>
7. </insert>
MS SQL Server配置
Xml代码
1. <!-- Microsoft SQL Server IDENTITY Column -->
2. <insertid="insertProduct-MS-SQL"parameterClass="com.domain.Product">
3. <![CDATA[insert into PRODUCT (PRD_DESCRIPTION) values(#description#) ]]>
4. <selectKeyresultClass="int"keyProperty="id"type="post">
5. <![CDATA[SELECT @@IDENTITY AS ID ]]>
6. <!-- 该方法不安全 应当用SCOPE_IDENTITY() 但这个函数属于域函数,需要在一个语句块中执行。 -->
7. </selectKey>
8. </insert>
上述MS SQL Server配置随是官网提供的配置,但实际上却恰恰隐患重重!按下述配置,确保获得有效主键。
Xml代码
1. <!-- Microsoft SQL Server IDENTITY Column 改进-->
2. <insertid="insertProduct-MS-SQL"parameterClass="com.domain.Product">
3. <selectKeyresultClass="int"keyProperty="id">
4. <![CDATA[insert into PRODUCT (PRD_DESCRIPTION) values(#description#)
5. SELECT SCOPE_IDENTITY() AS ID ]]>
6. </selectKey>
7. </insert>
MySQL配置
Xml代码
1. <!-- MySQL Last Insert Id -->
2. <insertid="insertProduct-Mysql"parameterClass="com.domain.Product">
3. <![CDATA[insert into PRODUCT(PRD_DESCRIPTION) values(#description#)]]>
4. <selectKeyresultClass="int"keyProperty="id">
5. <![CDATA[SELECT LAST_INSERT_ID() AS ID ]]>
6. <!-- 该方法LAST_INSERT_ID()与数据库连接绑定,同属统一会话级别,不会发生上述MS SQL Server的函数问题。 -->
7. </selectKey>
8. </insert>
通过以上方式,可以最大程度上确保插入数据的时候获得当前自增主键
- <!-- Oracle SEQUENCE Example using .NET 1.1 System.Data.OracleClient -->
- <insert id="insertProduct-ORACLE" parameterClass="product">
- <selectKey resultClass="int" type="pre"keyProperty="id">
- SELECT STOCKIDSEQUENCE.NEXTVAL AS VALUE 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" type="post"keyProperty="id">
- select @@IDENTITY as value
- </selectKey>
- </insert>
- <!-- MySQL Example -->
- <insert id="insertProduct-MYSQL" parameterClass="product">
- insert into PRODUCT (PRD_DESCRIPTION)
- values (#description#)
- <selectKey resultClass="int" type="post"keyProperty="id" >
- select LAST_INSERT_ID() as value
- </selectKey>
- </insert>