# The uniqueness of id and name combinations

**URL:** <https://forum.fixtrading.org/t/the-uniqueness-of-id-and-name-combinations/1055>\
**Category:** General Q&A\
**Tags:** xid\_169727, imported, fast-protocol\
**Created:** [January 27, 2009, 7:24pm UTC](https://forum.fixtrading.org/t/the-uniqueness-of-id-and-name-combinations/1055 "2009-01-27T19:24:13Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![declancaulfield\_x](https://avatars.discourse-cdn.com/v4/letter/d/bbce88/32.png) [@declancaulfield\_x](https://forum.fixtrading.org/u/declancaulfield_x)\
**Post date:** [January 27, 2009, 7:24pm UTC](https://forum.fixtrading.org/t/the-uniqueness-of-id-and-name-combinations/1055/1 "2009-01-27T19:24:13Z")

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Imported from previous forum

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**Author:** ![declancaulfield\_x](https://avatars.discourse-cdn.com/v4/letter/d/bbce88/32.png) [@declancaulfield\_x](https://forum.fixtrading.org/u/declancaulfield_x)\
**Post date:** [January 27, 2009, 7:24pm UTC](https://forum.fixtrading.org/t/the-uniqueness-of-id-and-name-combinations/1055/2 "2009-01-27T19:24:13Z")

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Heres a scenario:

Two “similar” templates embedded in a message with no reset in between.

In template 1 I have a field:

In template 2 I have a field:

There are two fields with identical names, one has an id the other does not.

What are the implications from a dictionary perspective? Are these the same dictionary field or different fields?

Cheers,

Declan

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**Author:** ![fplpo\_x](https://avatars.discourse-cdn.com/v4/letter/f/7ab992/32.png) [@fplpo\_x](https://forum.fixtrading.org/u/fplpo_x)\
**Post date:** [January 29, 2009, 8:21am UTC](https://forum.fixtrading.org/t/the-uniqueness-of-id-and-name-combinations/1055/3 "2009-01-29T08:21:12Z")

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[original email was from Mikael Brannstrom - m.brannstrom@ngm.se]  
Hi Declan,

The id has no meaning in FAST. It _can_ be used for mapping to another protocol above FAST, e.g. FIX where tag numbers would be used.

The two fields in your example will use the same dictionary entry if the templates 1 and 2 use the same dictionary (e.g. the ‘global’ dictionary that is the default).

/Mikael

> Heres a scenario:
> 
> Two “similar” templates embedded in a message with no reset in between.
> 
> In template 1 I have a field:
> 
> In template 2 I have a field:
> 
> There are two fields with identical names, one has an id the  
> other does not.
> 
> What are the implications from a dictionary perspective? Are these the  
> same dictionary field or different fields?
> 
> Cheers,
> 
> Declan