I followed the following procedure:
1) $ sudo pip install psycopg2
This gave me the following error
Downloading/unpacking psycopg2
Running setup.py egg_info for package psycopg2
no previously-included directories found matching 'doc/src/_build'
Installing collected packages: psycopg2
Running setup.py install for psycopg2
building 'psycopg2._psycopg' extension
llvm-gcc-4.2 -fno-strict-aliasing -fno-common -dynamic -g -Os -pipe -fno-common -fno-strict-aliasing -fwrapv -mno-fused-madd -DENABLE_DTRACE -DMACOSX -DNDEBUG -Wall -Wstrict-prototypes -Wshorten-64-to-32 -DNDEBUG -g -fwrapv -Os -Wall -Wstrict-prototypes -DENABLE_DTRACE -arch i386 -arch x86_64 -pipe -DPSYCOPG_DEFAULT_PYDATETIME=1 -DPSYCOPG_VERSION="2.4.3 (dt dec pq3 ext)" -DPG_VERSION_HEX=0x090004 -DPSYCOPG_EXTENSIONS=1 -DPSYCOPG_NEW_BOOLEAN=1 -DHAVE_PQFREEMEM=1 -I/System/Library/Frameworks/Python.framework/Versions/2.7/include/python2.7 -I. -I/usr/include -I/usr/include/postgresql/server -c psycopg/psycopgmodule.c -o build/temp.macosx-10.7-intel-2.7/psycopg/psycopgmodule.o
unable to execute llvm-gcc-4.2: No such file or directory
error: command 'llvm-gcc-4.2' failed with exit status 1
Complete output from command /usr/bin/python -c "import setuptools;__file__='/Users/boltellinfomedia/mukul/mukul/build/psycopg2/setup.py';exec(compile(open(__file__).read().replace('\r\n', '\n'), __file__, 'exec'))" install --single-version-externally-managed --record /tmp/pip-8NaS72-record/install-record.txt:
running install
running build
running build_py
running build_ext
building 'psycopg2._psycopg' extension
llvm-gcc-4.2 -fno-strict-aliasing -fno-common -dynamic -g -Os -pipe -fno-common -fno-strict-aliasing -fwrapv -mno-fused-madd -DENABLE_DTRACE -DMACOSX -DNDEBUG -Wall -Wstrict-prototypes -Wshorten-64-to-32 -DNDEBUG -g -fwrapv -Os -Wall -Wstrict-prototypes -DENABLE_DTRACE -arch i386 -arch x86_64 -pipe -DPSYCOPG_DEFAULT_PYDATETIME=1 -DPSYCOPG_VERSION="2.4.3 (dt dec pq3 ext)" -DPG_VERSION_HEX=0x090004 -DPSYCOPG_EXTENSIONS=1 -DPSYCOPG_NEW_BOOLEAN=1 -DHAVE_PQFREEMEM=1 -I/System/Library/Frameworks/Python.framework/Versions/2.7/include/python2.7 -I. -I/usr/include -I/usr/include/postgresql/server -c psycopg/psycopgmodule.c -o build/temp.macosx-10.7-intel-2.7/psycopg/psycopgmodule.o
unable to execute llvm-gcc-4.2: No such file or directory
error: command 'llvm-gcc-4.2' failed with exit status 1
----------------------------------------
Command /usr/bin/python -c "import setuptools;__file__='/Users/boltellinfomedia/mukul/mukul/build/psycopg2/setup.py';exec(compile(open(__file__).read().replace('\r\n', '\n'), __file__, 'exec'))" install --single-version-externally-managed --record /tmp/pip-8NaS72-record/install-record.txt failed with error code 1
Storing complete log in /Users/boltellinfomedia/.pip/pip.log
2) Then I searched on web for installing llvm-gcc-4.2 and from this http://developer.apple.com/library/mac/#releasenotes/DeveloperTools/RN-llvm-gcc/_index.html
got to know that I need to install Xcode
Also from this psycopg2 installation problem on OSX Lion I came to know that I can install psycopg2 via macports but then from this http://www.macports.org/install.php came to know that I need xcode again.
3) Finally I tried to install Xcode from apple store, it downloaded 1.6 gb file and after that says that it is now installed on my system. Here is the screenshot of the same
![macports installed image][1]
4) And then I tried to install macports via the dmg file available at http://www.macports.org/install.php but it says that xcode not yet installed on my system. Here is the screenshot of the same. ![when trying to install macport, xcode not installed message appears][2]
The problem most likely is that you only downloaded the Xcode INSTALLER from the App Store. You now need to run the installer to install Xcode.