File Format fields order

[Doug Easterbrook]

hi Xavier.

the question I might have is ‘why do you need this?’


we also have postgres, file formats, schemas and queries.


File formats are great — because they give you a bit of a data dictionary.  you can get variable name completion from file formats simply by starting to type the name,   an you can click to get the meaning of the variable.     it helps when we’ve got some 3500 plus field names in the database.

Schema’s for us are just an interim step in making the query.     you need a schema class so that you can use the variables in a query.  but they don’t do anything other than validate what you put in a query class.       order doesn’t matter.

the process for is generally:
- add variable to file class and give it names, types etc.
- add same variable to schema.


then we build a query of the data we want to use or display in lists on on windows.    It can cross mutliple postgres tables (a view, if you prefer, without making views in the postgres database).

we read those, in the order that we want to see the data on screen in lists….    so, only qiuery classes result in order-dependent variable names.


and then we update against the query class using some overrides in the table to allow us to update against query classes in a really efficient way .     the sql we create is far more efficient than the standard omnis insert/update/delete sql — in that it only uses variables that have changed.



anyway,    I imagine thats mostly what you are doing.


what I have not found a need for, though, is to have file format and schema names in the same order.





and the reason you cannot change file format field name order uses because omnis uses that order as part of its tokenization process.

when tokenizing, it uses the position of the field within the file format as a token number — it always has since omnis 3 days 35+ years ago.



thats been my experience —    If I had a better understanding of your need for this synchronicity between schemas and file formats. I might be able to suggest ways around a problem that you may be experiencing.









Doug Easterbrook
Arts Management Systems Ltd.
mailto:doug at artsman.com
http://www.artsman.com
Phone (403) 650-1978

> On September 28, 2021, at 12:22 AM, IT <it at plastipol.com> wrote:
> 
> My library runs against a Postgresql backend.
> But for every Schema I have an analogous File Format. I match field name and field position in the Schema and File Format.
> Schema can reorder positions or insert fields easy and no trouble, but File Formats are a trouble if you try to change field order or insert fields in middle of a File Format.
> 
> Is the any easy way to reorder or insert fields in a File Format?
> 
> regards
> 
> xavier
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