topic Re: Persistent classes - Locking a table before update in Application Development and Automation Discussions

Persistent classes - Locking a table before update

aditya_aghor — Sun, 06 Dec 2009 14:58:59 GMT

Hi guys,

I am thinking about using persistent classes for my CRUD application. However I am unclear about 1 thing... do i have to lock the Db tables before calling the SET_ methods or create_persistent methods ? I went to the SAP reference site Link: [http://help.sap.com/saphelp_nw04/helpdata/en/f5/a3682ebc6911d4b2e80050dadfb92b/content.htm] there they say that they have not implemented the Lock concept yet. Seems like persistent classes are missing a really fundamental thing if they do not lock a Db table before update( or am I misinterpreting something ? ).

So do I explicitly call the ENQUEUE n DEQUEUE FMs to lock the Db table before the SET_ methods? parallel access is possible in my app.

Re: Persistent classes - Locking a table before update

RichHeilman — Sun, 06 Dec 2009 23:57:16 GMT

So do I explicitly call the ENQUEUE n DEQUEUE FMs to lock the Db table before the SET_ methods?

Yes.

Regards,

Rich Heilman

Re: Persistent classes - Locking a table before update

aditya_aghor — Wed, 09 Dec 2009 05:49:03 GMT

Hi Rich,

1 more question .. if i have multiple Db tables related to 1 logical entity (eg Logical entity is customer and it has multiple Ztables to store customer's data) so I would have to create a persistent class for each of the Ztables correct ? then which of the following approaches is the best

1. Write a wrapper class to represent the Business entity customer and inside that wrapper class call the locking methods and the GET_ & SET_ methods

2. Add the other persistent classes as attributes of the main persistent class( as type ref to so that its corresponding GET_, SET_ methods are auto generated ). eg. IF the are two tables ZCUST, ZCUST_COMP_CODE then we would have 2 persistent classes. Should I add the persisent class of ZCUST_COMP_CODE to ZCUST ?

Re: Persistent classes - Locking a table before update

matt — Wed, 09 Dec 2009 10:36:03 GMT

You have to create a persistence class for each table.

Use option 1. Option 2 couples business meaning into your persistence layer.

matt

Re: Persistent classes - Locking a table before update

aditya_aghor — Thu, 10 Dec 2009 06:37:38 GMT

Thx guys!