Data frames were introduced in Stata 16 to allow working with multiple datasets in memory. In Stata 18, we added the capabilities to save and load a set of frames, known as a frameset.

We now introduce frames modify, which allows you to conveniently modify a frameset file without loading it into memory. You can add frames in memory to a frameset with frames modify, add(). You can drop a set of frames from a frameset with frames modify, drop().

Let's see it work

Suppose we are working with two longitudinal datasets to explore economic behavior over time. One of the datasets has information about labor outcomes of individuals over time (nlswork.dta), and the other has information about market values of companies over time (grunfeld.dta).

. frame create workers
. frame change workers
. webuse nlswork
(National Longitudinal Survey of Young Women, 14-24 years old in 1968)

. frame create companies
. frame change companies
. webuse grunfeld

We now save all frames in a frameset:

. frames save myframeset, frames(workers companies)
file myframeset.dtas saved

Now suppose we want to look into patterns of domestic research and development. We have a longitudinal dataset xtcoint.dta.

. frame create RandD
. frame change RandD
. webuse xtcoint
(Fictitious cointegration data)

We can add frames to the potentially large frameset without loading the latter into memory:

. frames modify using myframeset, add(RandD)
frame RandD added
file myframeset.dtas saved

We now have a frameset with three features of the economy over time:

. frames describe using myframeset, short



Frame: workers

Contains data                                 National Longitudinal Survey of
                                                Young Women, 14-24 years old in
                                                1968
 Observations:        28,534                  13 Mar 2025 11:22
    Variables:            21                  
Sorted by: idcode  year





Frame: companies

Contains data                                 
 Observations:           200                  13 Mar 2025 11:22                
    Variables:             6                  
Sorted by: company  year





Frame: RandD

Contains data                                 Fictitious cointegration data    
 Observations:        15,000                  13 Mar 2025 11:22
    Variables:             5                  
Sorted by: id  time

We can drop frames from the frameset without loading it:

. frames modify using myframeset, drop(workers)
frame workers dropped
file myframeset.dtas saved

We now have

. frames describe using myframeset, short



Frame: companies

Contains data
 Observations:           200                  13 Mar 2025 11:22
    Variables:             6
Sorted by: company  year





Frame: RandD

Contains data                                 Fictitious cointegration data
 Observations:        15,000                  13 Mar 2025 11:22
    Variables:             5
Sorted by: id  time