i haven't used it before but i think schematic just suitable for very small designs, you should be familiar with writing code. because if you design is big, schematic is not a good way.
good luck
It depends on CAD sofware. OrCAD, PADS a others may have VHDL generators. Instead you may use Qu@rtus or ISE schematic editor and redraw your design entirely. Presonally, I do'nt use schematic entry - direct writing VHDL code is better. Regards Pavel.
If You're working with ISE, You may use "Design Utilities" menu (processes window), option "View HDL Functional Model". There You'll find VHDL model of Your schematic design, simply copy it from there and paste in new file with .vhd extension.
I'm not using it, because i write code directly without schematic, but in OrCAD Capture you can create project for CPLD / FPGA design. Toolbar for Compile / Synthesis / P&R and simulation appears next to standard toolbars. Then you can draw schematics with sybols available in vendor library. Code is then generated from your schematics. You can write code directly too (menu File / New / VHDL file or Verilog file). Again - i have no practical experience with this type of CPLD / FPGA design. I only found it in OrCAD documentation and make some tests, but i know some people which are using this approach. IMHO drawing schematics of structure used in FPGA is redundant step and is more error-prone and time consuming than writing code directly.