table with infinite dynamically expandable columns veritcal rows propertes attributes eav otlt
If you need to have a table with attributes(columns) that need to be added dynamically, consider going vertically. There are various methods to add attributes to an entity by adding the attributes as rows.
you may be looking for these (Google them):
“OTLT” (One True Lookup Table)
attribute value system
Think deeply before you use any of these. Be careful you don't end up with a mess.
Dave’s guide to the EAV
OTLT and EAV: the two big design mistakes all beginners make
Entity-Attribute-Value (EAV) model with SQL Server 2005 xml datatype
An Introduction to Entity-Attribute-Value Design for Generic Clinical Study Data Management Systems
Explanation of many database models including EAV