Library Lost When Recompile

[Altera_Forum]

When i edit the design module, and recompile in modelsim, the library is lost. May i know why and how to retain it? 

 Everytime i need to add the statement like vsim -t 1ps -L altera_ver -L lpm_ver -L sgate_ver -L altera_mf_ver -L cycloneiii_ver -L rtl_work -L work -voptargs="+acc" encoding_tb

[Altera_Forum]

Hi, what do you mean by the library is lost? 

 If you re-compile a component into any of the librarys in use, you will need to restart simulation (stop, and then re-run vsim command, or do restart simulation from the GUI).  It is always nessasary to specify Verilog Librarys when you call vsim, either directly on the command line (as you have done) or via the GUI (unless they have been set as defaults, which I think Msim allows (via modelsim.ini file).

[Altera_Forum]

i recompile my design module. What i mean the lost library is the library provided by quartus II(Megafunction:RAM: 3 port). 

 The reason i asked is because i have seen someone to recompile without using vsim (i don c him type vsim in command console)