Repeating Groups in FIX

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Imported from previous forum

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[ original email was from Nikhil Bose - assistsoft@yahoo.com ]
Hello,

I have a couple of questions about repeating groups in FIX 4.1:

  1. Some repeating group count fields are marked as required, and some are not. For instance, NoIOIQualifiers in "Indication of Interest" is marked as not required. I assume that means if there are no IOIQualifiers, the NoIOIQualifiers field need not exist in the message. On the other hand, some such as NoRelatedSym in "News", are marked as required. Does this mean that even if there are no related symbols, NoRelatedSym must exist in the message, and be set to 0. Or does it mean that there must be at least 1 related sym in the message, and so NoRelatedSym must be greater than or equal to 1? Clarification would be greatly appreciated.

  2. In the "News" message, the related sym repeating group has some fields such a IDSource, with the comment, "Can be repeated mutiple times if message is related to multiple symbols". Does this mean this field must exist in each instance of the repeating group? That is, it is required for each instance of the repeating group. Conversely, a field such as PutOrCall, has the comment "For Options". This field may not exist in a given instance of the repeating group, if the related symbol in question is not an option.

Please let me know if my assumptions are incorrect, and what the right answers should be.

Thanks a lot,
Nikhil

3

The News message must have at least related symbol which is why the NoRelatedSym is required. Your assumption re: if you do not have any IOIQualifiers then you do not need to specify NoIOIQualifiers (the number of them) is correct.

  1. The related symbol repeating group consists of a set of related symbols. Each related symbol set must specify RelatdSym and can optionally specify any of the other symbol-related fields (through SecurityDesc in FIX 4.1) but only once. There are only a few instances in which a repeating group can contain a nested repeating group and they are indicated by additional indentation and it is noted (i.e. Allocation NoAllocs repeating group contains NoMiscFees repeating group). You cannot repeat SecurityID for a single RelatdSym field in the News or Email message.

Please note that repeating groups are order-specific and FIX 4.1 has attempted to make the first field in the repeating group required if the repeating group is used to faciliate parsing (i.e. use the presence of the first field in the repeating group to single a new group iteration).

> Hello,
>
> I have a couple of questions about repeating groups in FIX 4.1:
>
> 1) Some repeating group count fields are marked as required, and some are not. For instance, NoIOIQualifiers in "Indication of Interest" is marked as not required. I assume that means if there are no IOIQualifiers, the NoIOIQualifiers field need not exist in the message. On the other hand, some such as NoRelatedSym in "News", are marked as required. Does this mean that even if there are no related symbols, NoRelatedSym must exist in the message, and be set to 0. Or does it mean that there must be at least 1 related sym in the message, and so NoRelatedSym must be greater than or equal to 1? Clarification would be greatly appreciated.
>
> 2) In the "News" message, the related sym repeating group has some fields such a IDSource, with the comment, "Can be repeated mutiple times if message is related to multiple symbols". Does this mean this field must exist in each instance of the repeating group? That is, it is required for each instance of the repeating group. Conversely, a field such as PutOrCall, has the comment "For Options". This field may not exist in a given instance of the repeating group, if the related symbol in question is not an option.
>
> Please let me know if my assumptions are incorrect, and what the right answers should be.
>
> Thanks a lot,
> Nikhil
>
>

4

[ original email was from Valentin Melamed - valo@easetech.com ]
I am confused now. :slight_smile: The spec. says that RelatdSym is not required as well as every other field in the repeating group. This was the case in the previous versions of the protocol – the RelatdSym was not required. Frankly, we assumed that NoRelatedSym can be 0, hance no RelatdSym. Am I misreading the spec?

> The News message must have at least related symbol which is why the NoRelatedSym is required. Your assumption re: if you do not have any IOIQualifiers then you do not need to specify NoIOIQualifiers (the number of them) is correct.
>

5

Ok, you got me. Looks like we introduced a typo in version 4.1 when we added the field NoRelatedSym with status of required to News and Email. Since the body of the repeating group is not required, the number of instances field should not be required. This is consistent with the other messages (such as Allocation) which have had optional repeating groups. The other repeating group in News and Email (repeats around Text) is required as at least one instance of Text is required in the message. It is not the intention of the spec to have number-of fields be zero. The next release will have NoRelatedSym as not required.

> I am confused now. :slight_smile: The spec. says that RelatdSym is not required as well as every other field in the repeating group. This was the case in the previous versions of the protocol – the RelatdSym was not required. Frankly, we assumed that NoRelatedSym can be 0, hance no RelatdSym. Am I misreading the spec?
>
> > The News message must have at least related symbol which is why the NoRelatedSym is required. Your assumption re: if you do not have any IOIQualifiers then you do not need to specify NoIOIQualifiers (the number of them) is correct.
> >
>
>