jdbc and embedded sql

《jdbc and embedded sql》由会员上传分享，免费在线阅读，更多相关内容在工程资料-天天文库。

1、Chapter11JDBCandEmbeddedSQL453P:10CompCompRef8710-9ch11.vpThursday,February06,20031:14:05PM454J2ME:TheCompleteReferenceConnectedDeviceConfiguration(CDC)device–basedJ2MEapplicationinteractswithadatabasemanagementsystem(DBMS)usingJavadataobjectsandSQLAstate

2、mentsthatareembeddedintheJ2MEapplicationandexecutedbytheJavadataobjects.Javadataobjectsarediscussedinthepreviouschapter.ThischaptercontinueswithadetailedlookathowtocreateanSQLstatement,executethestatement,andinteractwithrowsofdatareturnedtotheJ2MEapplicationby

3、theDBMSinresponsetotherequestfordata.SQLispresentedinthischapterusingapracticalapproach.EachsectionofthechapterfocusesoncommontasksusedinaJ2MEapplicationratherthanonSQLkeywords.Thismeansyoucanquicklylocatearoutineinthechapter,thenincorporatetheroutinedirectlyi

4、ntoyourJ2MEcomponent.ModelProgramsManyprogrammingstylescanbeusedtowritethedata-accessportionofaJ2MEcomponent.Twoprogrammingstyles—referredtoasModelAandModelB—areusedinthischaptertoillustratehowaJ2MEapplicationcaninteractwithaDBMS.TheModelAprogramstyleisusedtoe

5、xecuteSQLrequeststhatusetheexecute()orexecuteUpdate()methods(seeChapter9)anddon’treturnaResultSet.TheModelBprogramstyleisusedtoexecuteSQLrequeststhatusetheexecuteQuery()method,whichreturnsaResultSet.Eachoftheseisdescribedindetailinthenexttwosectionsofthischapt

6、er.Bothprogramstylesaredesignedtominimizethecodeclutterinthischapter.Codeclutteroccurswhenevermanylinesofcodeareusedincodeexamples,butonlyafewlinesofcodechangebetweenexamples.Inanefforttoreducecodeclutter,eachcompleteprogrammodelispresentedatthebeginningofthec

7、hapter.OneortwocommentsindicatewherewithintheprogrammodeltoplacecodesegmentsthatareusedtoillustrateSQLroutinesthroughouttherestofthechapter.Thesecodesegmentsarecontainedeitherwithinatry{}blockorwithintheDownRow()method.Thetry{}blockiswheretheSQLstatementiscrea

8、tedandexecuted.TheDownRow()methodiswheretheJ2MEapplicationinteractswiththeResultSet.Let’ssaythatyouwanttoupdatearowinadatabase.Asyou’llrememberfromthepreviouschapter,theexecuteUpda