--- title: Mappings and transformations description: Mapping data sources to target systems via schema meta and transformation rules --- [Skip to content](https://help.zengines.ai/en/help/mappings-and-transformations#main-content) [![Zengines-logotype-black-rgb](https://help.zengines.ai/hs-fs/hubfs/Zengines-logotype-black-rgb.png?width=192&height=50&name=Zengines-logotype-black-rgb.png)](https://help.zengines.ai/en/help?hsLang=en) Open main navigation Close main navigation How can we help you? - There are no suggestions because the search field is empty. 1. [Zengines Data Platform Help](https://help.zengines.ai/en/help?hsLang=en) 2. [Data Migration](https://help.zengines.ai/en/help/data-migration?hsLang=en) 3. [Mapping](https://help.zengines.ai/en/help/data-migration?hsLang=en#mapping) August 24, 2026 # Mappings and transformations Data migration in Zengines is Target centric, by that we mean all source field mapping is captured and defined in terms of a Target field. A Target's tables and fields, one defined are shown in the Mapping section and can be filtered and sorted there. A Target can have mapping suggestions generated for it. A Target field can have assigned Source fields, and auto or custom transformations as well as a status (used to track progress and determine what fields are output in Conversion).  #### Mapping - Only Source fields (data) that are assigned to a Target field will be migrated via Conversion. - A Target field can have a number of Source fields that Zengines has determined are likely candidates, these are what we call 'suggested matches' - A Target field can have a number of 'assigned fields', these are Source fields that the user has decided are to be used to populate the data for the target field. - A Target field has a 'mapping status' to help manage workflow and testing. A field can be set by a user to: - Not started (no assigned Sources, no action taken on it) - In progress (this is automatically set when a Source is assigned) - Testing (user can set when ready) - Complete (user can set when ready, this triggers a validation check) - Blocked (user can set) - A mapping can have assigned Source fields, whose data can be auto-transformed, passed through, other custom transformed through a specific user defined rule. - A mapping can be Locked/unlocked to prevent any editing, depending on the user's role and specific project restrictions. - A mapping can have a simple text based explanation added to it so that complex transformation rules can be easily understand by non technical observers. - Mappings can be reset (have assigned Sources removes and custom transformations cleared). - All target field mapping changes are audit logged and also appear as a change log in the Notes tab. **Assigning Sources** - When matches are generated for a Target, Zengines analyzes all Sources set to 'ready', scores the individual fields, and surfaces star rated recommendations for the best Source field matches. - Assigning a Source field to a Target field is done in the 'Select Sources' view of a selected field on the Mapping grid, any source field can be used, whether recommended or not. - A single assigned Source field can be 'auto-transformed' (this will simply try to ensure any Target field data type constraints are met). A 'custom transformation' can be added to override this. - Multiple Source fields from different Sources and tables can be assigned to a Target field, this will require a 'custom transformation'. - It is not necessary to use all assigned Source fields, although assigned Source fields are used to inform JOIN statement suggested requirements when defining a Conversion Job. Thus it is recommended to unassign any Source fields that have been assigned but are no longer needed. #### **Custom transformations** - Using the [Zengines Transformation Language](https://help.zengines.ai/en/help/zengines-transformation-language?hsLang=en), custom SQL based rules can be written to manipulate the assigned Source fields so that the output value satisfies the Target field requirements. - A custom rule can only use Source fields that have been assigned in that mapping. - All rules can be tested using the example data set on the Source fields, or directly input into the example data area. - Any custom transformations must be 'valid' to be set the mapping to 'complete'. - The Zengines AI 'Rule generator' can be used to create the code for SQL transformation rule. - [General](https://help.zengines.ai/en/help/general?hsLang=en#main-content) - [Releases](https://help.zengines.ai/en/help/general?hsLang=en#releases) - [Data Migration](https://help.zengines.ai/en/help/data-migration?hsLang=en#main-content) - [Getting started](https://help.zengines.ai/en/help/data-migration?hsLang=en#getting-started) - [Migration projects](https://help.zengines.ai/en/help/data-migration?hsLang=en#migration-projects) - [Migration assets](https://help.zengines.ai/en/help/data-migration?hsLang=en#migration-assets) - [Sources and Targets](https://help.zengines.ai/en/help/data-migration?hsLang=en#sources-and-targets) - [Mapping](https://help.zengines.ai/en/help/data-migration?hsLang=en#mapping) - [Conversions](https://help.zengines.ai/en/help/data-migration?hsLang=en#conversions) - [Data Lineage](https://help.zengines.ai/en/help/data-lineage?hsLang=en#main-content) - [Getting Started](https://help.zengines.ai/en/help/data-lineage?hsLang=en#getting-started) - [Language Primers](https://help.zengines.ai/en/help/data-lineage?hsLang=en#language-primers) - [Analysis](https://help.zengines.ai/en/help/data-lineage?hsLang=en#analysis) - [Zengines Assist](https://help.zengines.ai/en/help/data-lineage?hsLang=en#zengines-assist) - [Platform Management](https://help.zengines.ai/en/help/platform-management?hsLang=en#main-content) - [Administration](https://help.zengines.ai/en/help/platform-management?hsLang=en#administration) - [Technical Resources](https://help.zengines.ai/en/help/technical-resources?hsLang=en#main-content) - [Templates](https://help.zengines.ai/en/help/technical-resources?hsLang=en#templates) - [Utilities](https://help.zengines.ai/en/help/utilities?hsLang=en) [![zengines-avatar-black](https://help.zengines.ai/hs-fs/hubfs/zengines-avatar-black.png?width=40&height=40&name=zengines-avatar-black.png "zengines-avatar-black")](https://zengines.ai) [zengines.ai](http://zengines.ai) Copyright © 2026, Zengines