Django Extensions provides a bunch of management commands for the Django Framework. One of the most handy is the graph_models command. This command creates a visual representation of the Django models existing in the database.
In order to use this command you need to have Graphviz and PyGraphviz installed on your machine. Graphviz is a package of open-source tools for representing structural information as diagrams of abstract graphs and networks. PyGraphviz is a Python interface for Graphviz and allows you can create, edit, read, write, and draw Graphviz graphs.
Download and install Graphviz from this link: http://www.graphviz.org/Download_windows.php.
I couldn’t install PyGraphviz using easy_install, because it depends on Graphviz, and easy_install doesn’t know where to find Graphviz.
Download PyGraphviz(1.1) from this link: http://networkx.lanl.gov/download/pygraphviz/, and extract it.
Adjust “setup.py” file to reflect your Graphviz instalation.
library_path='C:/Program Files (x86)/Graphviz 2.28/lib/release/lib'
include_path='C:/Program Files (x86)/Graphviz 2.28/include/graphviz'
Normally, you would run python setup.py install to build and install a python application, but in this case we need to do some extra work. Running this command will output an error:
"Unable to find vcvarsall.bat"
To solve this issue, PyGraphviz needs to be compiled with a MSVC or mingw32 compiler. I haven’t found a Windows build for PyGraphviz so the only option was to built this myself.
I have used an older release of mingw because the current one doesn’t support the mno-cygwin argument anymore.
Download and install mingw-get-inst-20100831.exe from this link:
Add mingw/bin directory to the system path.
Change line 285 from “c:\python27\lib\distutils\unixcompiler.py” from
compiler = os.path.basename(sysconfig.get_config_var("CC"))
compiler = "gcc".
or there will be an error “TypeError: ‘NoneType’ object is unsubscriptable”. Change it back after finishing installing PyGraphviz.
Now it’s time to build PyGraphviz:
C:\pygraphviz-1.1>python setup.py build -c mingw32
copying pygraphviz\agraph.py -> build\lib.win32-2.7\pygraphviz
copying pygraphviz\graphviz.py -> build\lib.win32-2.7\pygraphviz
copying pygraphviz\release.py -> build\lib.win32-2.7\pygraphviz
copying pygraphviz\version.py -> build\lib.win32-2.7\pygraphviz
copying pygraphviz\__init__.py -> build\lib.win32-2.7\pygraphviz
copying pygraphviz\tests\test.py -> build\lib.win32-2.7\pygraphviz\tests
copying pygraphviz\tests\__init__.py -> build\lib.win32-2.7\pygraphviz\tests
copying pygraphviz\tests\attributes.txt -> build\lib.win32-2.7\pygraphviz\tests
copying pygraphviz\tests\graph.txt -> build\lib.win32-2.7\pygraphviz\tests
copying pygraphviz\tests\layout_draw.txt -> build\lib.win32-2.7\pygraphviz\tests
copying pygraphviz\tests\unicode.txt -> build\lib.win32-2.7\pygraphviz\tests
building 'pygraphviz._graphviz' extension
C:\MinGW\bin\gcc.exe -mno-cygwin -mdll -O -Wall -IC:/Graphviz/include/graphviz -
IC:\Python27\include -IC:\Python27\PC -c pygraphviz/graphviz_wrap.c -o build\tem
pygraphviz/graphviz_wrap.c: In function 'agattr_label':
pygraphviz/graphviz_wrap.c:2855:5: warning: return makes integer from pointer wi
thout a cast
C:\MinGW\bin\gcc.exe -mno-cygwin -shared -s build\temp.win32-2.7\Release\pygraph
viz\graphviz_wrap.o build\temp.win32-2.7\Release\pygraphviz\_graphviz.def -LC:/G
raphviz/lib/release/lib -LC:\Python27\libs -LC:\Python27\PCbuild -Wl,-RC:/Graphv
iz/lib/release/lib -lcgraph -lcdt -lpython27 -lmsvcr90 -o build\lib.win32-2.7\py
Copy the contents of the build/lib.win32-2.7 directory(single sub-folder called pygraphviz) into your Python’s site-packages folder.
You can create a PNG image file called my_project_visualized.png with application grouping running the following command:
manage.py graph_models -a -g -o my_project_visualized.png
Minimalist GNU for Windows
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I did what you have said above but it gives error as:January 21, 2012 at 4:53 am
“error: command ‘gcc’ failed no such file or directory”
You didn’t add mingw/bin directory to the system path.March 13, 2012 at 2:47 pm
Hi, I follow the steps you introduce, and in the last part, I don’t understand this sentence.
“Copy the contents of the build/lib.win32-2.7 directory(single sub-folder called pygraphviz) into your Python’s site-packages folder.”
1, do you mean copy “C:pygraphviz-1.1uildlib.win32-2.7pygraphviz” this directory?April 19, 2012 at 4:18 am
2, what is Python’s site-packages folder?
After following the steps you gave, I got the the install massage you paste there. Besides, it still gives error as:April 19, 2012 at 4:25 am
“c:/mingw/bin../lib/gcc/mingw32/4.5.0/../../../mingw32/bin/ld.exe: cannot find -lcgraph
c:/mingw/bin../lib/gcc/mingw32/4.5.0/../../../mingw32/bin/ld.exe: cannot find -lcdt
collect2: ld returned 1 exit status
error: command ‘gcc’ failed with exit status 1”
Sorry to trouble again, I know what the last sentence mean now, but I still have the error message, do you know how to deal with it?April 19, 2012 at 4:31 am
Hi, there, my problem have been solved, I just want to add if others still have the same problem here.
If change the library path toApril 19, 2012 at 7:54 am
my install process would work successfully.
I have installed PyGraphviz twice. First time I had the library_path similar to yours. After several months, when I had to do the steps again I didn’t remember which installer/build versions to use. So the second time I have stored this information in the article hoping that will be helpful for other people that run into the same issue.April 25, 2012 at 9:55 am
according to your method,but i failed to install pygraphviz.next setp,I am stuped,so what i can’t know do?June 4, 2012 at 3:17 pm
I add mingw/bin directory to the system path and also apply to compiler = “gcc”, it gives error as:“error: command ‘gcc’ failed no such file or directory”.