Mail Merge and Reporting

Mail Merge is a popular feature for quickly and easily creating documents such as letters, labels, and envelopes. Aspose.Words enables you to generate documents from templates with Mail Merge fields.

A Mail Merge field is a field that you can insert into a mail merge template to include specific values from a data source record in output documents. For example, you can insert a merge field in an email template so that the greeting will have the recipient’s first name rather than a generic “Hello!”. Aspose.Words places data from an external source, such as a database or file, into these fields and formats them. The resulting document is saved in the specified folder.

Aspose.Words takes the standard Mail Merge functionality and advances it many steps ahead, turning it into a full-fledged reporting solution that allows you to create even more complex documents such as reports, catalogs, inventories, and invoices. Here are a few advantages of the Aspose.Words reporting solution:

• Design reports in Microsoft Word using standard Mail Merge fields
• Define regions in the document that are growing, such as detailed order rows (currently is not supported in Python version)
• Insert images during a mail merge
• Execute any custom logic, control formatting, or insert complex content using Mail Merge event handlers (currently is not supported in Python version)
• Fill in documents with data from any type of data source (currently is not supported in Python version, only arrays data source is supported)

The aspose.words.mailmerging module is used to work with mail merging.

Mechanism and Main Components of a Mail Merge Operation

Aspose.Words provides the ability to load documents in various supported formats and then allows users to perform a Mail Merge operation.

Usually, a loaded document allows you to store merge fields, for example, a document in DOCX format. But there are formats that do not store such fields, for example, TXT. If Aspose.Words supports loading such file formats, you can add the merge fields directly to the document model, save the document in a convenient supported format, and perform the Mail Merge operation.

The Mail Merge operation will merge your mail merge template and your data source to generate individual merged documents.

What is a Mail Merge Template

The goal of applying a mail merge operation using a merge template is to simplify the process of creating a document.

There are several ways to create and design a merge template. You can use Microsoft Word, and the merge template does not have to be a Microsoft Word template, that is a document in the DOT or DOTX format, it can be a regular document in the DOC or DOCX format. You need to insert some special fields called merge fields into this template in places where you want data from your data source to be later inserted. Or you can programmatically create a merge template using the DocumentBuilder class.

The merge template contains the main text, which should be the same in all output documents after you perform the Mail Merge operation. You can use any format for your template if there is an ability to add merge fields to it. All merge fields within your template will be filled in from your data source during the Mail Merge operation.

Data Source Types for a Mail Merge Operation

Currently Aspose.Words for Python via .NET Mail Merge accepts only an array of values as a data source. Other types will be added int the future versions.

The following code example shows how to create a simple template and fill it with data using Mail Merge functionality:

Merged Documents of a Mail Merge Operation

A merged document is the result of the Mail Merge operation when you merge the template with the data source. All merge fields within the merged document are replaced with actual data from your data source.

The following image shows an example of the merge template with merged fields before performing the Mail Merge operation.

The following image shows an example of the output merged document as a result of performing the Mail Merge operation.

See Also

• Work with Mail Merge templates in Word

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FAQ

1. Q: What data source types can I use with Mail Merge in Aspose.Words for Python?
   A: In the current Python via .NET version only an array of objects (e.g., a list of dictionaries or a list of custom objects) is supported as the data source. Other data source types such as DataTable or IDataReader are not yet available but are planned for future releases.

2. Q: Can I use mail‑merge regions (repeating rows) in the Python version?
   A: No. Mail‑merge regions, which allow a table row to repeat for each record, are not supported in the Python via .NET API at this time. You would need to perform the repetition manually using a loop and DocumentBuilder or wait for a future update.

3. Q: After performing a mail merge, how can I generate a Table of Contents automatically?
   A: Insert a TOC field ({ TOC \\o "1-3" \\h \\z \\u }) in the template before the merge. After the merge completes, call doc.update_fields() to refresh the TOC. Example:

   doc = Document("TemplateWithToc.docx")
   doc.mail_merge.execute(data)
   doc.update_fields()
   doc.save("ResultWithToc.docx")