Unable to auto update/ delimit records in a SAP custom table

[esskay]

I have a custom table with the following fields:

mandt, assgn_code char8, disp_code char4, assign_text char40, begda datum, endda datum, updated_by aenam, updated_on, created_by aenam, created_on.

Out of these fields, mandt, assgn_code, disp_code, assign_text, begda are KEY fields.

I want to achieve this:

1. Whenever a new entries is created using table maintenance, the created_by and created_on fields should be updated. This is done using table maintenance event (05).

2. Whenever an existing record is updated using table maintenance (user shall be able input ONLY assgn_text and begda), the existing record should be delimited with endda = <user input start date> - 1 and the update_by and the updated_on fields are updated automatically. In addition to this, a new record should be inserted with the user inputted (i.e user changed) assgn_text, the begda = <user input start date> and the created_by and the created_on fields are updated accordingly. "This I am unable to get it DONE".

I tried enabling the delimit option in the TMG, but this is NOT working as per my requirement (may be I am missing something). This only updates the new record with the begda = <user input start date> but does NOT update the endda of the existing (delimited) record.

I am completely NEW to this SAP development. Requesting the community help me with this step by step.

Thank you, Regards,