Training: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 track all the changes done on an object and retrieve old versions of that object with operators like allInstancesAtTime, atTime, or 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:

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