View source for Documentation:Versioned on class

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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 track all the changes done on an object and retrieve old versions of that object with operators like [[OCLOperators allInstancesAtTime|allInstancesAtTime]], [[OCLOperators atTime|atTime]], or [[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 one 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
|}
[[Category:Advanced]]
[[Category:SQL]]