DDOs support several find messages that allow you to find a record without disturbing the state of current DDO. This allows you to take advantage of a DDO’s current constraints without having to actually update your DDO and its attached DEOs. These messages are useful if you need to check the status of some other record, but you do not wish to disturb the contents of the current record in a DDO.
These messages are referred to a “Read” messages to distinguish them from the more normal “Find” messages which do update the DDOs. The “Read” messages are listed below with their corresponding “Find” messages. The parameters used by the “Read” and “Find” messages are the same:
Message is |
A non DDO Updating version of |
Because the Read messages to do not update the DDO, you should always use the File-Buffers to evaluate their values.
// count number of users without changing the current User in the DDO
Function CountUsers returns integer
Handle hoDD
Boolean bOK
Integer iCount
Move oUser_DD to hoDD
Send Request_Read of hoDD FIRST_RECORD Users.File_Number 1
Move (Found) to bOK
While (bOK)
Increment iCount
Send Request_Read of hoDD GT Users.File_Number 1
Move (Found) to bOK
Loop
Function_Return iCount
End_function
Find and Clear Operations in DDOs