Modulenotfounderror no module named psycopg2 windows

I can confirm psycopg2 is install (using conda install -c anaconda psycopg2) but the it seems psycopg2 cannot be imported to my python script or the interpreter is unable to locate it. I also tried installing using pip3, requirements are satisfied, meaning psycopg2 is already istalled, but cannot understand why I script isn’t able to import it. Using Mac (OS v10.14.4)

$ python create_tables.py
Traceback (most recent call last):
  File "create_tables.py", line 1, in <module>
    import psycopg2
ModuleNotFoundError: No module named 'psycopg2'

$ pip3 install psycopg2
Requirement already satisfied: psycopg2 in /usr/local/lib/python3.7/site-packages (2.8.2)
$ pip3 install psycopg2-binary
Requirement already satisfied: psycopg2-binary in /usr/local/lib/python3.7/site-packages (2.8.2)
python -V
Python 3.7.0

Any idea why this happen?

EDIT: create_table.py

import psycopg2
from config import config


def create_tables():
    """ create tables in the PostgreSQL database"""
    commands = (
        """
        CREATE TABLE vendors (
            vendor_id SERIAL PRIMARY KEY,
            vendor_name VARCHAR(255) NOT NULL
        )
        """,
        """ CREATE TABLE parts (
                part_id SERIAL PRIMARY KEY,
                part_name VARCHAR(255) NOT NULL
                )
        """,
        """
        CREATE TABLE part_drawings (
                part_id INTEGER PRIMARY KEY,
                file_extension VARCHAR(5) NOT NULL,
                drawing_data BYTEA NOT NULL,
                FOREIGN KEY (part_id)
                REFERENCES parts (part_id)
                ON UPDATE CASCADE ON DELETE CASCADE
        )
        """,
        """
        CREATE TABLE vendor_parts (
                vendor_id INTEGER NOT NULL,
                part_id INTEGER NOT NULL,
                PRIMARY KEY (vendor_id , part_id),
                FOREIGN KEY (vendor_id)
                    REFERENCES vendors (vendor_id)
                    ON UPDATE CASCADE ON DELETE CASCADE,
                FOREIGN KEY (part_id)
                    REFERENCES parts (part_id)
                    ON UPDATE CASCADE ON DELETE CASCADE
        )
        """)
    conn = None
    try:
        # read the connection parameters
        params = config()
        # connect to the PostgreSQL server
        conn = psycopg2.connect(**params)
        cur = conn.cursor()
        # create table one by one
        for command in commands:
            cur.execute(command)
        # close communication with the PostgreSQL database server
        cur.close()
        # commit the changes
        conn.commit()
    except (Exception, psycopg2.DatabaseError) as error:
        print(error)
    finally:
        if conn is not None:
            conn.close()


if __name__ == '__main__':
    create_tables()

A common error you may encounter when using Python is modulenotfounderror: no module named ‘psycopg2’.

This error occurs when the Python interpreter cannot detect the Psycopg library in your current environment.

You can install Psycopg2 in Python 3 with python3 -m pip install psycopg2-binary.

This tutorial goes through the exact steps to troubleshoot this error for the Windows, Mac and Linux operating systems.

ModuleNotFoundError: no module named ‘psycopg2’

What is ModuleNotFoundError?

The ModuleNotFoundError occurs when the module you want to use is not present in your Python environment. There are several causes of the modulenotfounderror:

The module’s name is incorrect, in which case you have to check the name of the module you tried to import. Let’s try to import the re module with a double e to see what happens:

import ree

---------------------------------------------------------------------------
ModuleNotFoundError                       Traceback (most recent call last)
1 import ree

ModuleNotFoundError: No module named 'ree'

To solve this error, ensure the module name is correct. Let’s look at the revised code:

import re

print(re.__version__)

2.2.1

You may want to import a local module file, but the module is not in the same directory. Let’s look at an example package with a script and a local module to import. Let’s look at the following steps to perform from your terminal:

mkdir example_package

cd example_package

mkdir folder_1

cd folder_1

vi module.py

Note that we use Vim to create the module.py file in this example. You can use your preferred file editor, such as Emacs or Atom. In module.py, we will import the re module and define a simple function that prints the re version:

import re

def print_re_version():

    print(re.__version__)

Close the module.py, then complete the following commands from your terminal:

cd ../

vi script.py

Inside script.py, we will try to import the module we created.

import module

if __name__ == '__main__':

    mod.print_re_version()

Let’s run python script.py from the terminal to see what happens:

Traceback (most recent call last):
  File "script.py", line 1, in ≺module≻
    import module
ModuleNotFoundError: No module named 'module'

To solve this error, we need to point to the correct path to module.py, which is inside folder_1. Let’s look at the revised code:

import folder_1.module as mod

if __name__ == '__main__':

    mod.print_re_version()

When we run python script.py, we will get the following result:

2.2.1

Lastly, you can encounter the modulenotfounderror when you import a module that is not installed in your Python environment.

What is Psycopg2?

Psycopg2 is a PostgreSQL database adapter for Python. It provides an API to connect to an external database.

The simplest way to install psycopg2 is to use the package manager for Python called pip. The following installation instructions are for the major Python version 3.

Always Use a Virtual Environment to Install Packages

It is always best to install new libraries within a virtual environment. You should not install anything into your global Python interpreter when you develop locally. You may introduce incompatibilities between packages, or you may break your system if you install an incompatible version of a library that your operating system needs. Using a virtual environment helps compartmentalize your projects and their dependencies. Each project will have its environment with everything the code needs to run. Most ImportErrors and ModuleNotFoundErrors occur due to installing a library for one interpreter and trying to use the library with another interpreter. Using a virtual environment avoids this. In Python, you can use virtual environments and conda environments. We will go through how to install psycopg2 with both.

How to Install Psycopg2 on Windows Operating System

First, you need to download and install Python on your PC. Ensure you select the install launcher for all users and Add Python to PATH checkboxes. The latter ensures the interpreter is in the execution path. Pip is automatically on Windows for Python versions 2.7.9+ and 3.4+.

You can check your Python version with the following command:

python3 --version

You can install pip on Windows by downloading the installation package, opening the command line and launching the installer. You can install pip via the CMD prompt by running the following command.

python get-pip.py

You may need to run the command prompt as administrator. Check whether the installation has been successful by typing.

pip --version

Psycopg2 installation on Windows Using pip

To install psycopg2, first create the virtual environment. The environment can be any name, in this we choose “env”:

virtualenv env

You can activate the environment by typing the command:

envScriptsactivate

You will see “env” in parenthesis next to the command line prompt. You can install psycopg2 within the environment by running the following command from the command prompt.

python3 -m pip install psycopg2-binary

We use python -m pip to execute pip using the Python interpreter we specify as Python. Doing this helps avoid ImportError when we try to use a package installed with one version of Python interpreter with a different version. You can use the command which python to determine which Python interpreter you are using.

How to Install Psycopg2 on Mac Operating System using pip

Open a terminal by pressing command (⌘) + Space Bar to open the Spotlight search. Type in terminal and press enter. To get pip, first ensure you have installed Python3:

python3 --version

Python 3.8.8

Download pip by running the following curl command:

curl https://bootstrap.pypa.io/get-pip.py -o get-pip.py

The curl command allows you to specify a direct download link. Using the -o option sets the name of the downloaded file.

Install pip by running:

python3 get-pip.py

To install psycopg2, first create the virtual environment:

python3 -m venv env

Then activate the environment using:

source env/bin/activate 

You will see “env” in parenthesis next to the command line prompt. You can install psycopg2 within the environment by running the following command from the command prompt.

python3 -m pip install psycopg2-binary

How to Install Psycopg2 on Linux Operating Systems

All major Linux distributions have Python installed by default. However, you will need to install pip. You can install pip from the terminal, but the installation instructions depend on the Linux distribution you are using. You will need root privileges to install pip. Open a terminal and use the commands relevant to your Linux distribution to install pip.

Installing pip for Ubuntu, Debian, and Linux Mint

sudo apt install python-pip3

Installing pip for CentOS 8 (and newer), Fedora, and Red Hat

sudo dnf install python-pip3

Installing pip for CentOS 6 and 7, and older versions of Red Hat

sudo yum install epel-release

sudo yum install python-pip3

Installing pip for Arch Linux and Manjaro

sudo pacman -S python-pip

Installing pip for OpenSUSE

sudo zypper python3-pip

Psycopg2 installation on Linux with Pip

To install psycopg2, first create the virtual environment:

python3 -m venv env

Then activate the environment using:

source env/bin/activate 

You will see “env” in parenthesis next to the command line prompt. You can install psycopg2 within the environment by running the following command from the command prompt.

Once you have activated your virtual environment, you can install psycopg2 using:

python3 -m pip install psycopg2-binary

Installing Psycopg2 Using Anaconda

Anaconda is a distribution of Python and R for scientific computing and data science. You can install Anaconda by going to the installation instructions. Once you have installed Anaconda, you can create a virtual environment and install psycopg2.

To create a conda environment you can use the following command:

conda create -n psycopg2 python=3.8

You can specify a different Python 3 version if you like. Ideally, choose the latest version of Python. Next, you will activate the project container. You will see “psycopg2” in parentheses next to the command line prompt.

source activate psycopg2

Now you’re ready to install psycopg2 using conda.

Once you have activated your conda environment, you can install psycopg2 using the following command:

conda install -c anaconda psycopg2

Check Psycopg2 Version

Once you have successfully installed psycopg2, you can check its version. If you used pip to install psycopg2, you can use pip show from your terminal.

python3 -m pip show psycopg2-binary

Name: psycopg2-binary
Version: 2.9.3
Summary: psycopg2 - Python-PostgreSQL Database Adapter

Second, within your python program, you can import psycopg2 and then reference the __version__ attribute:

import psycopg2
print(psycopg2.__version__)

2.9.3

If you used conda to install psycopg2, you could check the version using the following command:

conda list -f psycopg2

# Name                    Version                   Build  Channel
psycopg2                  2.8.5            py38hddc9c9b_0    anaconda

Summary

Congratulations on reading to the end of this tutorial. The modulenotfounderror occurs if you misspell the module name, incorrectly point to the module path or do not have the module installed in your Python environment. If you do not have the module installed in your Python environment, you can use pip to install the package. However, you must ensure you have pip installed on your system. You can also install Anaconda on your system and use the conda install command to install psycopg2.

Go to the online courses page on Python to learn more about Python for data science and machine learning.

For further reading on missing modules in Python, go to the article:

• How to Solve Python ModuleNotFoundError: no module named ‘urllib2’.
• How to Solve ModuleNotFoundError: no module named ‘plotly’.
• How to Solve Python ModuleNotFoundError: no module named ‘boto3’.

Have fun and happy researching!

Skip to content

Traceback (most recent call last):
  File "", line 1, in 
ModuleNotFoundError: No module named 'psycopg2'

pip install psycopg2
or
pip install psycopg2-binary
or
pip3 install psycopg2

C:UserskarunakarDesktopPy Practice>pip install psycopg2
Collecting psycopg2
  Downloading https://files.pythonhosted.org/packages/79/ad/327e9c1e09b91e57294eb9a38492fcb000f15c028a1b716714fee5be802e/psycopg2-2.8.4-cp38-cp38-win32.whl (986kB)
     |████████████████████████████████| 993kB 133kB/s
Installing collected packages: psycopg2
Successfully installed psycopg2-2.8.4

 sudo apt-get install libpq-dev

Quick Fix: Python raises the ImportError: No module named 'psycopg2' when it cannot find the library psycopg2. The most frequent source of this error is that you haven’t installed psycopg2 explicitly with pip install psycopg2. Alternatively, you may have different Python versions on your computer, and psycopg2 is not installed for the particular version you’re using.

Problem Formulation

You’ve just learned about the awesome capabilities of the psycopg2 library and you want to try it out, so you start your code with the following statement:

import psycopg2

This is supposed to import the Pandas library into your (virtual) environment. However, it only throws the following ImportError: No module named psycopg2:

>>> import psycopg2
Traceback (most recent call last):
  File "<pyshell#6>", line 1, in <module>
    import psycopg2
ModuleNotFoundError: No module named 'psycopg2'

Solution Idea 1: Install Library psycopg2

The most likely reason is that Python doesn’t provide psycopg2 in its standard library. You need to install it first!

Before being able to import the Pandas module, you need to install it using Python’s package manager pip. Make sure pip is installed on your machine.

To fix this error, you can run the following command in your Windows shell:

$ pip install psycopg2

This simple command installs psycopg2 in your virtual environment on Windows, Linux, and MacOS. It assumes that your pip version is updated. If it isn’t, use the following two commands in your terminal, command line, or shell (there’s no harm in doing it anyways):

$ python -m pip install --upgrade pip
$ pip install pandas

💡 Note: Don’t copy and paste the $ symbol. This is just to illustrate that you run it in your shell/terminal/command line.

Solution Idea 2: Fix the Path

The error might persist even after you have installed the psycopg2 library. This likely happens because pip is installed but doesn’t reside in the path you can use. Although pip may be installed on your system the script is unable to locate it. Therefore, it is unable to install the library using pip in the correct path.

To fix the problem with the path in Windows follow the steps given next.

Step 1: Open the folder where you installed Python by opening the command prompt and typing where python

Step 2: Once you have opened the Python folder, browse and open the Scripts folder and copy its location. Also verify that the folder contains the pip file.

Step 3: Now open the Scripts directory in the command prompt using the cd command and the location that you copied previously.

Step 4: Now install the library using pip install psycopg2 command. Here’s an analogous example:

After having followed the above steps, execute our script once again. And you should get the desired output.

Other Solution Ideas

• The ModuleNotFoundError may appear due to relative imports. You can learn everything about relative imports and how to create your own module in this article.
• You may have mixed up Python and pip versions on your machine. In this case, to install psycopg2 for Python 3, you may want to try python3 -m pip install psycopg2 or even pip3 install psycopg2 instead of pip install psycopg2
• If you face this issue server-side, you may want to try the command pip install --user psycopg2
• If you’re using Ubuntu, you may want to try this command: sudo apt install psycopg2
• You can check out our in-depth guide on installing psycopg2 here.
• You can also check out this article to learn more about possible problems that may lead to an error when importing a library.

Understanding the “import” Statement

import psycopg2

In Python, the import statement serves two main purposes:

• Search the module by its name, load it, and initialize it.
• Define a name in the local namespace within the scope of the import statement. This local name is then used to reference the accessed module throughout the code.

What’s the Difference Between ImportError and ModuleNotFoundError?

What’s the difference between ImportError and ModuleNotFoundError?

Python defines an error hierarchy, so some error classes inherit from other error classes. In our case, the ModuleNotFoundError is a subclass of the ImportError class.

You can see this in this screenshot from the docs:

You can also check this relationship using the issubclass() built-in function:

>>> issubclass(ModuleNotFoundError, ImportError)
True

Specifically, Python raises the ModuleNotFoundError if the module (e.g., psycopg2) cannot be found. If it can be found, there may be a problem loading the module or some specific files within the module. In those cases, Python would raise an ImportError.

If an import statement cannot import a module, it raises an ImportError. This may occur because of a faulty installation or an invalid path. In Python 3.6 or newer, this will usually raise a ModuleNotFoundError.

Related Videos

The following video shows you how to resolve the ImportError:

The following video shows you how to import a function from another folder—doing it the wrong way often results in the ModuleNotFoundError:

How to Fix “ModuleNotFoundError: No module named ‘psycopg2′” in PyCharm

If you create a new Python project in PyCharm and try to import the psycopg2 library, it’ll raise the following error message:

Traceback (most recent call last):
  File "C:/Users/.../main.py", line 1, in <module>
    import psycopg2
ModuleNotFoundError: No module named 'psycopg2'

Process finished with exit code 1

The reason is that each PyCharm project, per default, creates a virtual environment in which you can install custom Python modules. But the virtual environment is initially empty—even if you’ve already installed psycopg2 on your computer!

Here’s a screenshot exemplifying this for the pandas library. It’ll look similar for psycopg2.

The fix is simple: Use the PyCharm installation tooltips to install Pandas in your virtual environment—two clicks and you’re good to go!

First, right-click on the pandas text in your editor:

Second, click “Show Context Actions” in your context menu. In the new menu that arises, click “Install Pandas” and wait for PyCharm to finish the installation.

The code will run after your installation completes successfully.

As an alternative, you can also open the Terminal tool at the bottom and type:

$ pip install psycopg2

If this doesn’t work, you may want to set the Python interpreter to another version using the following tutorial: https://www.jetbrains.com/help/pycharm/2016.1/configuring-python-interpreter-for-a-project.html

You can also manually install a new library such as psycopg2 in PyCharm using the following procedure:

• Open File > Settings > Project from the PyCharm menu.
• Select your current project.
• Click the Python Interpreter tab within your project tab.
• Click the small + symbol to add a new library to the project.
• Now type in the library to be installed, in your example Pandas, and click Install Package.
• Wait for the installation to terminate and close all popup windows.

Here’s an analogous example:

Here’s a full guide on how to install a library on PyCharm.

• How to Install a Library on PyCharm

This article will help you, how to fix the ModuleNotFoundError: No module named ‘psycopg2’, No module named ‘flask_sqlalchemy’ or ModuleNotFoundError: No module named ‘MODULE_NAME’  in python.

Solution – ModuleNotFoundError: No module named ‘psycopg2’

{Read:- 5 Ways to Improve SEO on Your WordPress Site }

To fix the No module named ‘psycopg2’ error, you have to install the dependent library as well as psycopg2 Module.

Python 3-

Python 2-

Solution – ModuleNotFoundError: No module named ‘flask_sqlalchemy’

Python 3-

Python 2-

Solution – ModuleNotFoundError: No module named ‘MODULE_NAME’

{Read:- How to Build a WordPress Site in 1 Day }

Python 3-

Python 2-