Orsiso

Asynchronous SQL in Flex Jerome Poudevigne Aureliant CTO

OrSiSo ,[object Object],[object Object],[object Object]

SQLite use by OrSiSo ,[object Object],[object Object]

OrSiSo - contention on DB ,[object Object],[object Object],[object Object],[object Object]

Synchronous cache update ZZZ…. Data arrives Local cache updated Now you can use it again…

Asynchronous : Why ? “ Because synchronous operations execute in the main execution thread, all application functionality (including refreshing the screen and allowing mouse and keyboard interaction) is paused while the database operation or operations are performed.” For long-running operations this can cause a noticeable pause in the application .

Async data set loading ,[object Object],[object Object],[object Object]

[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

SQLConnection-synchronous ,[object Object],try { SQLStatement.exec(“ SOME SQL ”); SQLStatement.exec(“ MORE SQL ”); } catch (…) { }

Asynchronous (100’s of XML items) Update in the background User interface never locked Data arrives

SQLConnection-asynchronous ,[object Object],Stmt.text=“DO SOME SQL”; stmt.addEventListener(COMPLETE, OnNextStep ); stmt.execute(); … Function onNextStep (e:SQLEvent) { stmt.text=“DO MORE SQL” stmt.addEventListener(COMPLETE, onDone ); stmt.execute(); } Function onDone (e:SQLEvent) { // Whew ! }

Issues ,[object Object],[object Object]

Transactions-asynchronous ,[object Object],Connection.beginTransaction(); Stmt.text=“DO SOME SQL”; stmt.execute(); Stmt.text=“DO SOME SQL”; stmt.execute(); Stmt.text=“DO SOME SQL”; stmt.execute(); Connection.commit(); Does not work. In Async mode Flex does not guarantee that SQL execution is in the same order as the Flex lines of code…

Transactions-asynchronous ,[object Object],Connection.beginTransaction(); Function onStarted(..) { Stmt.text=“DO SOME SQL”; stmt.addEventListener(COMPLETE, OnNextStep ); stmt.execute(); } Function onNextStep (e:SQLEvent) { stmt.text=“DO MORE SQL” stmt.addEventListener(COMPLETE, onDone ); stmt.execute(); } Function onDone (e:SQLEvent) { // Whew !! And what if I had 150 of these… }

A solution : StatementList class ,[object Object],public class StatementList extends EventDispatcher { public function StatementList( conn:SQLConnection, statements:Object, withTransaction:Boolean= false ) public function execute (): void }

[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

Still having issues… ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],Function onClickListFriends(..) { Stmt.text=“SELECT FRIENDS WHERE”; stmt.execute (); } Guaranteed locking…

One level (of abstraction) up… ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

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