Everything WIMS tracks is called a variable. The WIMS users are trained to identify variables by their names and variable numbers. Internally, each variable has a unique identifier and hence variable name and/or number can be changed at any time.
Variable descriptions are stored inside the VARDESC table.  The most important fields that define a variable are VARID,VARNUM,NAME and VARTYPE. The source query for this figure is the following:
select varid,varnum,name,vartype from vardesc

Column descriptions:

VARID –A unique identifier for a variable.
VARNUM – Numeric identifier for a variable that’s available to users.
NAME – Variable name.
VARTYPE – Variable type. The VARTYPE column defines the type of a particular variable. Different columns of the VARDESC table need to be populated depending on VARTYPE.

WIMS currently supports the following variable types:
 P – Daily variable / parameter
 C – Daily calculated variable
 T – Daily text variable
 4 – Daily Detail variable tracked every 4 hours
 G – 4 hour calc.
 E – 4 hour text variable
 H – Daily Detail variable tracked every hour
 N – Hourly Calc
 B – Hourly Text
 3 – Daily Detail variable tracked every 30 minutes
 W – 30 Minute Calc
 Q – 30 Minute Text
 F – Daily Detail variable tracked every 15 minutes
 V – 15 Minute Calc
 X – 15 Minute Text
 5 – Daily Detail variable tracked every 5 minutes
 Y – 5 Minute Calc
 R – 5 Minute Text
 1 – Daily Detail variable tracked every minute
 S – Minute Calc
 A – Minute Text