Hi Dave!

I think your analysis is correct. 
I believe the numbers are as follows:

Max field length: 255 bytes 
Max number of  fields:  255 (as someone pointed out, if you need that 
many, it's bad database design)
Max length of record: ~4000 bytes (quickly reached if you join in some 
Access tables)
Max Tab file size: 2 GB (OS limit, not MapInfo)

I have noted on some occasions that some data tables have very long 
character fields, 255 bytes.
I believe this data to be of Access origin, and originally were memo 
fields which have no limit length in Access.
As the DB structure of MI cannot handle memo fields they probably get the 
max character field length when put into the MI DB format.
Imagine what will happen if you have a number of such fields, the 4000 
byte barrier is reached very quickly.

Hälsning / Best regards Mats.E
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"David Baker" <[EMAIL PROTECTED]> 
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2006-01-24 01:06
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RE: [MI-L] Number of fields






On 23 Jan 2006 at 22:27, Peter Horsbøll Møller <[EMAIL PROTECTED]> wrote:

> As far as I remember there is a limit of 4000 bytes per record

Ah, thank you Sir - you've probably just solved a long-standing problem 
I've had. I have 
a Microsoft Access table with only 56 fields that I call from MapInfo, but 
found that I got 
strange errors when adding a new field. I can't remember the actual error 
message, 
but it wasn't anything logical to me, and took ages to figure out that it 
was caused by 
this extra field being added. So, I went without the field, knowing that I 
hadn't reached 
the 255 field limit, but must have bumped into some other limitation.

Dave
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