Posting key is a two digit number which plays a very crucial role in posting an accounting document. As per standard practice, each key is used for a specific business transaction. Standard sap offer large number of predefined key. Custom key can also be created but often not required since large number of predefined key are good enough to serve the business requirement.
Let’s understand posting key with example
Double book keeping mandates that, in every document sum of debit amount should be equal to sum of credit amount. Net of debit and credit in an accounting document should always be zero. Hence every accounting document will have some line items with debit balance and some line items with credit balance.
For example consider below document
Dr. is represented by number 40
Cr. Is represented by number 50
These numbers are called posting key. There are many more keys, each having specific purpose.
Posting key controls below
Type of posting: Debit or Credit
A PostingKey can only perform one action either debit or credit.
Example: key 40 is for debit, key 50 is for credit
Permitted account type: Asset/ customer/ vendor/ material/ GL account
In any accounting document, line item will have below fields entered
PostingKey + account + amount
PostingKey decides which type of account can be used with it.
Field status: Suppress/ display/ optional/ required
As we already know, while posting an accounting document “input fields behave as per their status in field status group which is assigned to GL master”.
But field status group is not the only thing which controls field status; field status is also controlled by posting key(PK).
Field status conflicts between posting key and field status group
For a particular field, status in posting key might be different from status in field status group.
Then sap finalized the status in below order:
First priority Suppress: If the field status is 'suppress' in any of the two (posting key and field status group). Field status suppress prevails while posting document.
Second priority Display: If the field status is 'display' in any of the two (posting key and field status group). Field status display prevails while posting document.
Third priority Optional: If the field status is 'optional' in any of the two (posting key and field status group). Field status optional prevails while posting document.
Last priority Required: This field status gets the last preference.
To read about field status group: http://sapconcepthub.com/field-status-variant/