Connecting two databases and writting in single query?

Question

There are 2 seperate DB involved and both were phisically 2 different places. In my application, I used spring batch and implemented like this:

1.Fetching all ids from AS/400 database(Master DB) 2.comparing with MY SQL db (my application) ids and what ever Ids existed in sql db, I am updating those IDS information to My local DB(MY SQL). Disadvantage : Assume AS400 DB has 10 ids and in my Application has only 2 ids, but in order to get this data I am actually reading all 10 Ids. so waste of time and lack of efficiency right?!

Here is the code I am using in spring batch to fetch data :

<bean id="patternsItemReader" class="org.springframework.batch.item.database.JdbcCursorItemReader">
                    <property name="sql" value="SELECT
                                                        J3PATT AS patternId,
                                                        J3PTYP AS patternType,
                                                        J3CLAS AS PatternClass,
                                                        J3REPT AS repeat,
                                                        j3CLRS AS numOfColors,
                                                        JOENTT AS event,
                                                        J3ACT AS activity
                                                        FROM TEST006966.JQP030H a WHERE rrn(a) >=( select max(rrn(b)) from
                                                        TEST006966.JQP030H b where a.j3patt = b. j3patt) and j3sts = 'N' ORDER BY
                                                        J3PATT, JODATE desc ,jotime desc
                                                        "/>

                        <property name="rowMapper">
                                    <bean class="org.springframework.jdbc.core.BeanPropertyRowMapper">
                                                <property name="mappedClass" value="com.mohawkind.batch.patterns.PatternsRowMapper"/>
                                    </bean>
                        </property>
                        <property name="dataSource" ref="AS400DataSource" />
            </bean>

        <bean id="patternsItemWriter" class="com.mohawkind.batch.patterns.PatternsWritter" />

What I am looking for :

I want a solution to only fetch data what is existed in my local(SQL DB). is it possible to connecting 2 db and fetching data through spring batch jobs??

Any ideas,suggestions will greatly appreciated. Thanks in advance..

Answer 1

您无法使用此查询创建数据库视图吗？