View source for Documentation:Versioned on class

When you set Versioned on a class we never use sql-command-update or delete for that class. Instead we use insert with TimeStampStart and TimeStampStop added as non-attribute-db-columns.

You can now track all the changes done on an object - and retrieve old versions of that object with operators like [[OCLOperators allInstancesAtTime|allInstancesAtTime]], [[OCLOperators atTime|atTime]], [[OCLOperators objectTimeStamp|objectTimeStamp]]

If Class1 is versioned this is a valid expression:
 Class1.allinstances.changepoints(0,-1)->collect(x|x,x.objectTimeStamp, x.objectTimeStamp.timeStampToTime,x.objectTimeStamp.timeStampToTime.timeToTimeStamp)
Class1.allinstances.changepoints(0,-1): Gives a list of all versions of all Class1 objects

x.objectTimeStamp : gives the integer number timestamp

x.objectTimeStamp.timeStampToTime : looks up the corresponding calendar datetime from ClockLog

x.objectTimeStamp.timeStampToTime.timeToTimeStamp : looks up the integer timestamp from a datetime

I had 1 Class1 object that I had changed 3 times:
{| class="wikitable"
|Eco.Framework.Impl.Frontside.DefaultLoopback
|0
|2022-10-26 13:09:25
|0
|-
|Eco.Framework.Impl.Frontside.DefaultLoopback
|1
|2022-10-26 13:09:28
|1
|-
|Eco.Framework.Impl.Frontside.DefaultLoopback
|2
|2022-10-26 15:56:48
|2147483647
|}