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Generate Keyfield Serial Number by Auto-entry or Calculation?

Question asked by Sorbsbuster on Nov 18, 2009
Latest reply on Nov 18, 2009 by Sorbsbuster


Generate Keyfield Serial Number by Auto-entry or Calculation?


I got my fingers burned a long time ago with importing records in FM3, and have been wary of this characteristic ever since.  Suggesting I 'go test it' would be logical, but I am hoping someone can assure me, one way or the other.


All The Manuals say that one should create a KeyField by setting it as 'Auto-enter, increment by 1, prohibit modification, etc.'  I understand all that, and used to use it regularly.  But then one day I imported a set of existing records into an updated clone, and when I checked the details for that field (in 'Define Fields...') it showed that the 'Next value..' box had NOT correctly anticipated, or updated, what the next value should be.  Had I continued to use the file as usual it would have generated a short series of duplicated key values.  Ever since then (about 1886, I confess) I have auto-generated the key serial number field using a SelfRelationshipByConstant, setting the Key Field to be Max(SelfRelationship::KeyField) + 1.  I have never experienced any problem with importing existing data into a new file since.


Can someone re-assure me that I have been wasting my time?  I recognise that another parameter is whether or not, upon import, I select 'Update Look-ups, etc...'.  I admit the horrible experience of all those years ago scarred me.  I have studiously designed all of my files to allow me to avoid - at all costs - ever ticking the option to 'Update Look-ups...'etc.


In other words: if I resort to generating my KeyField using 'auto-enter a serial number', will importing existing records into an updated clone correctly set the 'Next Incremental Value' correctly, EVERY TIME?


Thanks in anticipation of sleeping easy again,