Develop Reference

Import data from excel spreadsheet to django model

I'm building a website that'll have a django backend. I want to be able to serve the medical billing data from a database that django will have access to. However, all of the data we receive is in excel spreadsheets. So I've been looking for a way to get the data from a spreadsheet, and then import it into a django model. I know there are some different django packages that can do this, but I'm having a hard time understanding how to use these packages. On top of that I'm using python 3 for this project. I've used win32com for automation stuff in excel in the past. I could write a function that could grab the data from the spreadsheet. Though what I want figure out is how would I write the data to a django model? Any advice is appreciated.

Use http://www.python-excel.org/ and consider this process:
Make a view where user can upload the xls file.
Open the file with xlrd. xlrd.open_workbook(filename)
Extract, create dict to map the data you want to sync in db.
Use the models to add, update or delete the information.
If you follow the process, you can learn a lot of how loading and extracting works and how does it fits with the requirements. I recommend to you first do the step 2 and 3 in shell to get more quicker experiments and avoid to be uploading/testing/error with a django view.
Hope this kickoff base works for you.

Why don't you use django-import-export?
It's a widget that allows you to import excel files from admin section.
It's very easy to install, here you find the installation tutorial, and here an example.

Excel spreadsheets are saved as .csv files, and there are plenty of examples and explanations on how to work with them, such as here and here, online already.
In general, if you are having difficulty understanding documentation or packages, my advice would be to search for specific examples or see if whatever you are trying to do has already been done. Play with it to get a working understanding, and then modify it to fit your needs.

How to extract serialised data from Access

I want to enable a user to export some data to a web application I am building. The data from the legacy application can be accessed through MS Acces (ODBC). The web application is written in Django/Python, but that is not very relevant.
The user would have to export data from time to time and import it into the web app. The table structure in the web app more-or-less mirrors the one in the legacy application.
My question of how to get the data from Access to a format that is easily parseable in the web app. The data is from 5 different tables and interrelated. Is there a way to serialise the data from Access into an XML / JSON file? I know that you can do an XML export, but as far as I know that is limited to a query, so I wouldn't have the hierarchy... Is there a VBA library to help with the task?

You can reference Microsoft XML, v5.0 (or whatever version) in the Visual Basic Editor and create XML programmatically.
See
- Simple example
- Introduction to XML in Microsoft Windows (in depth example)

Answering my own question here. I did some googling and it looks like you can export data from a table together with selected other tables. For that, it is necessary to draw the relationships within Access.
That might also solve my problem (and without composing the XML manually). Will find out if this works and check back later.
source: http://msdn.microsoft.com/en-us/library/office/aa167823(v=office.11).aspx#odc_accessnewxmlfeatures_includingrelatedtableswhenexportingxml

Python Excel - OpenPyxl Limitation

I recently started to automate a report at work using Python. Since my data was provided to me in the form of an excel sheet, I felt the best way to do this was to use an excel python module. My module of choice was openpyxl. It worked great, I've used it to perform calculations and organise my data ready to plot charts. Now here's the problem...
I know that you cannot update existing charts using openpyxl so that option went out the window.
What I then tried to do was link the data in my openpyxl spreadsheet to another spreadsheet containing the charts (which is then linked to my word document where the charts are to be displayed). So after doing this I ran my script and to my annoyance, the data links between my openpyxl spreadsheet and charts spreadsheet had been severed. I guess this is because openpyxl creates a new spreadsheet when you save using the save function links are severed.
My question is.. are there any ways to maintain the data links?

It is currently not possible to maintain links between files. I think it would be possible to keep them metadata but, for fairly obvious reasons, it won't necessarily be possible to validate them. This best way for this to happen would be through a pull request.
If you're on Windows you might look at using the Python for Windows stuff which will allow you to remote control the applications.

Generating correct excel xls format

I created a little script in python to generate an excel compatible xml file (saved with xls extension). The file is generated from a part database so I can place an order with the extracted data.
On the website for ordering the parts, you can import the excel file so the order fills automatically. The problem here is that each time I want to make an order, I have to open excel and save the file with xls extension of type MS Excel 97-2003 to get the import working.
The excel document then looks exactly the same, but when opened with notepad, we cannot see the xml anymore, only binary dump.
Is there a way to automate this process, by running a bat file or maybe adding some line to my python script so it is converted in the proper format?
(I know that question has been asked before, but it never has been answered)

There are two basic approaches to this.
You asked about the first: Automating Excel to open and save the file. There are in fact two ways to do that. The second is to use Python tools that can create the file directly in Python without Excel's help. So:
1a: Automating Excel through its automation interface.
Excel is designed to be controlled by external apps, through COM automation. Python has a great COM-automation interface inside of pywin32. Unfortunately, the documentation on pywin32 is not that great, and all of the documentation on Excel's COM automation interface is written for JScript, VB, .NET, or raw COM in C. Fortunately, there are a number of questions on this site about using win32com to drive Excel, such as this one, so you can probably figure it out yourself. It would look something like this:
import win32com.client
excel = win32com.client.Dispatch('Excel.Application')
spreadsheet = excel.Workbooks.Open('C:/path/to/spreadsheet.xml')
spreadsheet.SaveAs('C:/path/to/spreadsheet.xls', fileformat=excel.xlExcel8)
That isn't tested in any way, because I don't have a Windows box with Excel handy. And I vaguely remember having problems getting access to the fileformat names from win32com and just punting and looking up the equivalent numbers (a quick google for "fileformat xlExcel8" shows that the numerical equivalent is 56, and confirms that's the right format for 97-2003 binary xls).
Of course if you don't need to do it in Python, MSDN is full of great examples in JScript, VBA, etc.
The documentation you need is all on MSDN (since the Office Developer Network for Excel was merged into MSDN, and then apparently became a 404 page). The top-level page for Excel is Welcome to the Excel 2013 developer reference (if you want a different version, click on "Office client development" in the navigation thingy above and pick a different version), and what you mostly care about is the Object model reference. You can also find the same documentation (often links to the exact same webpages) in Excel's built-in help. For example, that's where you find out that the Application object has a Workbooks property, which is a Workbooks object, which has Open and Add methods that return a Workbook object, which has a SaveAs method, which takes an optional FileFormat parameter of type XlFileFormat, which has a value xlExcel8 = 56.
As I implied earlier, you may not be able to access enumeration values like xlExcel8 for some reason which I no longer remember, but you can look the value up on MSDN (or just Google it) and put the number 56 instead.
The other documentation (both here and elsewhere within MSDN) is usually either stuff you can guess yourself, or stuff that isn't relevant from win32com. Unfortunately, the already-sparse win32com documentation expects you to have read that documentation—but fortunately, the examples are enough to muddle your way through almost everything but the object model.
1b: Automating Excel via its GUI.
Automating a GUI on Windows is a huge pain, but there are a number of tools that make it a whole lot easier, such as pywinauto. You may be able to just use swapy to write the pywinauto script for you.
If you don't need to do it in Python, separate scripting systems like AutoIt have an even larger user base and even more examples to make your life easier.
2: Doing it all in Python.
xlutils, part of python-excel, may be able to do what you want, without touching Excel at all.

Is there a Python library that can generate charts within Excel?

I know python can manipulate Excel data but I don't know whether it can generate charts in it.
Does such a library exist?

Excel is an OLE Automation server (which is built on COM), which means it has a discoverable interface that makes it possible to automate it from any tool that understands COM. Providing you're on Windows, Python is one of many such tools and you already have (or can easily obtain) the library you need: it's PythonCom.
See this snippet for an example of how a Python script uses the library to talk to Excel. It doesn't seem to explicitly work with charts, so you'll need to figure that out for yourself: try using the Macro Recorder to get an idea (in VBA) of how to achieve what you want, then translate that into Python.
If you're not running on Windows, then you're going to need code that understands the Excel file format, which is fairly achievable in the new xlsx/xlsm XML-based world (available from Excel 2007 onwards) and rather more difficult in the old binary xls form.