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Long fields or Memo when migrating from DFD?


Started by Charmaine
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Long fields or Memo when migrating from DFD?

I have to pick your brain, we do not use Long fields , but have done a conversion for a client from 4.53 to De 8, they have a couple of Long fields , do I change these to Memo fields in De 8 , or what would you suggest ?

And the exports and imports of the Data , how do we do this then ? 


Written by Charmaine 17/04/18 at 11:18:55 Dataease [{8}]FIVE

Re:Long fields or Memo when migrating from DFD?

Long in DE was obviously not that long. Typically just a couple of hundred characters.


Long in DE8 is up to 4K

and Memo is 4MB in DE8 and 4GB in DE9.

Long fields are stored as a number of text fields in the DBM when memos are stored in separate files.

If you use the long/memo as a "slightly" larger text field you should keep them as long (this is why we re-introduced them) but if it is to store large unstructured text like a document or an article etc. then Memo.

The efficiency of Memo has been quite poor in DE7/DE8 but it is much increased in DE9 and will be further increased as we move forward.

Memo is a very important storage object in DE which will be more and more important as we move forward as you can store anything in them like pictures, documents, zip files and even databases ;-)

You can export a memo the same as everything else. The problem is more how it's used. To export a memo in a CSV if it is 4MB large and contain a document is obviously not going to work as the likelihood of it containing a character used to separate the CSV is to high.

You will have the same problem with both LongText and Memo when it comes to carriage return as any text field that allow multiline will possibly have a line change in it.

So the problem is not really what fields you are exporting but the export format.

The traditional , and CR to separate fields and records will not work with either so you simply need to use a more "clever" format.

This might not be relevant but when memos are used with HTML or more advanced formatting you should export it as separate files with MemoWriteToFile().

The good news of course is that in DE9 onwards you will have the ability to read and write directly to any application remotely without the need of exporting/importing as before.


Written by DataEase 17/04/18 at 11:30:13 Dataease [{8}]FIVE