---
title: Target Definition
slug: segment/target-definition
docTags: 
createdAt: 2026-01-15T19:47:27.897Z
---

By Target Definition you determine how and where your segmented audience is saved. This is done setting up the output container, known as the [Target Data Extension](docId\:Y2nMBGSEGCTlxl6-eAc1S), which receives your matching records after the Selection runs.

## How it works

Target Definition serves as the structural blueprint for your final query output. While the previous step determines *which* audience you are targeting, this step defines how and where that segmented audience will be saved. Once the Selection executes, the Target Data Extension acts as your deliverable and functions as a standard SFMC Data Extension that can be used in Journeys, Automations, or other marketing campaigns.

Hence, in Target Definition, you establish the structure of your output database and determine how those records should be written. To this end, you can apply configurations such as:

- [Create & Edit Target Data Extensions](docId\:l0tfmaMrtE2XjxOU-JCHb)**:** You can select an existing Target Data Extension by browsing your folders or generate a new one on-the-fly. There is no limit to the number of Data Extensions you can create.
- [Field Mapping](docId:7w-YENpxyaOeRZfR5cxuI)**:** You map your source data fields to the fields in your Target Data Extension. You can also modify field properties, configure sendable settings for email campaigns, and apply Data Retention Policies.
- [Data Actions](docId\:HUBrcvXI3lX2VDZTSwba8)**:** You define the rules for how data is written into your target container by choosing to **Overwrite** existing data, **Append** new records, or** Update** matching records.
- [Source Limiting](docId\:qquyTu8oZc7blA_TWLkNZ): Apply different size limits to the generated results of different sources or tabs.
- [Prio Deduplication](docId\:VKR1reInYO3puLdkKdvoU): Apply deduplication rules to handle and remove duplicate records.
- [Custom Values](docId\:L1w6vTgYZSIIruJK4SY32): Enrich your results with new fields not found in your source tables, such as fixed values, conditional logic, timestamps, row numbers, date differences, or database aggregations.
- [Sort & Limit](docId\:NF7GE8i2obyodwPdsDBV9): Sort your results (either randomly or by a specific field) and restrict the output to a specified record limit or percentage for audience capping or A/B testing.