topic Re: Locking only certain fields of a table using lock objects in Application Development and Automation Discussions

Locking only certain fields of a table using lock objects

Former Member — Tue, 18 Aug 2009 05:48:58 GMT

Hi,

I am aware that we can lock an entire table using locking.

However i was wondering how we can use lock objects to lock specific Fields of a table for specfic records

Re: Locking only certain fields of a table using lock objects

Former Member — Tue, 18 Aug 2009 05:59:36 GMT

Hi,

Yes. You can lock individual records based on the Key Fields. Use the FM: ENQUEUE_E_TABLE.

In the parameter VARKEY, concatenate your Key Field values and pass it to the above FM. So only the particular record will be locked.

Parameters:

TABNAME

VARKEY

Regards,

Chathia.

Re: Locking only certain fields of a table using lock objects

Former Member — Tue, 18 Aug 2009 09:44:46 GMT

Hi Sarvesh,

Yes, its possible to lock the table at record level.

You can lock individual records based on the Key Fields only.

suppose if you have created a lock object EZMARA, then two FMs will be created, one for locking the table at record level and one for unlocking it,

FMs:

ENQUEUE_EZMARA

DEQUEUE_EZMARA

to lock the table at record level you need to call ENQUEUE_EZMARA and assign the keyfield value ( for which record you need to lock)

Pls dont forget to unlock the record one updation is done.

Infact this is a good programming practice in Database systems.

Rgds,

Sripal

Re: Locking only certain fields of a table using lock objects

Rui_Dantas — Tue, 18 Aug 2009 13:01:11 GMT


> However i was wondering how we can use lock objects to lock specific Fields of a table for specfic records

If I understand correctly, the original poster wants to lock specific fields.

Sarvesh, keep in mind that:

- A lock using SAP lock objects only works if others updating the table also always call the lock function. That is, if this is a Z table you have to make sure you call the lock function before each update (and unlock afterwards).

- If you do this with a specific Z lock object before you update the fields you want (but not before other different fields are updated) then you should get what you want.

- If what you want is actually to lock specific records then forget what I just said and read the answers above.

Re: Locking only certain fields of a table using lock objects

Former Member — Tue, 18 Aug 2009 14:01:10 GMT

Hi Sarvesh,

It is possible to lock a database table at a record (row) level but not at a field level. For example you can lock all the lines of a sales order in table VBAP by specifying the client (MANDT) and order number (VBELN) in function module ENQUEUE_EMVBAP. However it is not possible to lock table for say a specified material number. Locking is always possible either for the entire table or for a combination of the primary key.

Certain tables have lock objects that have lock modules. For example VBAP has a lock object EMVBAP. Lock object EMVBAP

has lock modules ENQUEUE_EMVBAP for locking and DEQUEUE_EMVBAP for unlocking locked records in table VBAP. Not all database tables have lock objects.

When a table does not have lock objects assigned to it you can use the generic function module ENQUEUE_E_TABLEE and DEQUEUE_E_TABLEE to do the same thing. Function module ENQUEUE_E_TABLEE has a parameter VARKEY. You need to pass a concatenation of the fields values (in the primary key) that you want to lock. for example if you order number is '9999999999' and you client is '010' then VARKEY = '0109999999999'. If sales oder '9999999999' has hundred line items all the line items will get locked. If I want to just lock line item '000030' then VARKEY = '0109999999999000030'. Make sure you add the leading zeros for VBELN and POSNR while constructing the VARKEY parameter. I am not sure if you can lock records using ''. For example if I want to lock all records in VBAP where POSNR is '000030', I am not sure if this can be done by say VARKEY = '010000030'.

Another thing that you need to keep in mind with locking records is that you want to make sure that you do not create too many locks. I think there is a limit on the number of records you can lock at one time.

Let me know if this helps.

Regards,

Mark