> ## Documentation Index > Fetch the complete documentation index at: https://docs.reelevant.com/llms.txt > Use this file to discover all available pages before exploring further. # Datagraph Entity Groups > Define an output contract shared by several Datagraph Entities, bind the Entities to it, and publish it ## Overview A [Datagraph Entity Group](/glossary) is an output contract shared by several Datagraph Entities. It lets several Entities — one per country, per brand, or per recommendation algorithm — be interchangeable for the consumer that reads them. Open **DataHub → Datagraph → Entity groups** — *Define output contracts shared by a set of entities*. The listing shows each group with its **Name**, the number of **Fields** in the contract, the number of member **Entities**, its **Status** (**Draft** or **Live**), and **Last update**, plus two actions: **Edit** and **Delete**. **Create group** opens the editor on a new Draft. Entity groups listing showing the listings_recommendations group with five fields, two entities and a Draft status ## Before You Begin * The Entities you want to bind must exist and, to publish the group, must have a Live version. See [Datagraph Entities](/advanced-guide/datahub/datagraph/entities). * Creating and editing groups requires the Datagraph Entity permission. See [Permissions](/product-guide/account/permissions). ## Editor Layout The toolbar holds the group **Name**, the **Save** action, the **Publish** action, and a **Versions** side panel, exactly as in the Entity editor. | Field | Description | | --------------- | ----------------------------------------------------------------------------- | | **Name** | The group identifier. Use snake\_case, for example `product_recommendations`. | | **Description** | Optional. What the group is for, in business terms. | Below the toolbar, two sections define the contract and its members. Entity group editor with the Name, Save and Publish controls, five output fields with their types and Required or Nullable toggles, and two member Entities marked Conform ### Fields **Fields** lists the outputs every member Entity must provide. Click **Add field** to declare one. | Column | Description | | --------------- | -------------------------------------------------------------------------------------------------------------------------------------- | | **Name** | The output column name the Entity must return, for example `product_id`. | | **Type** | The expected type. It uses the same type list as Entity parameters, for example `string`, `number`, `boolean`, `datetime`, `string[]`. | | **Description** | Optional. What the field contains. | | **Required** | When enabled, an Entity that does not return this column violates the contract. When disabled, the column may be absent. | | **Nullable** | Documents that the value can be empty for some rows. | ### Entities **Entities** lists the Entities bound to this contract. Pick them in **Select entities...**; each member then shows its **Conformance**: | Status | Meaning | | ------------------- | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | **Conform** | The Live version of the Entity returns every required field with a compatible type. | | **No live version** | The Entity has never been published. The group can be saved but not published while it is a member. | | **N violation(s)** | The Live version misses a required field, or returns it with an incompatible type. Each violation is listed under the Entity name, for example *Missing field "price"*. | Conformance is checked against the Live version of each Entity, so an unpublished change to an Entity has no effect until it is published. ## Conformance Rules * A required field must be present in the Entity output with a compatible type. * An optional field may be absent. When present, its type must still be compatible. * Two types are compatible when identical, or when they share the same primitive — `datetime` and `datetime_iso` both resolve to a date, for example. * Extra output columns returned by an Entity are ignored. The contract is enforced on both sides. Saving or publishing a group fails with *Entity group contract violated* when a member does not conform. Publishing an Entity fails with the same error when its new output would break a Live group it belongs to, and an Entity listed in a Live group cannot be deleted. ## Worked Example The property listings model from [Datagraph Entities](/advanced-guide/datahub/datagraph/entities) has two Entities that return listings: `recommended_listings` and `listings_matching_search`. A Content that displays a listing card needs the same columns whichever Entity the Workflow selects. | Field | Type | Required | Nullable | | ------------- | -------- | -------- | -------- | | `id_listing` | `string` | Yes | No | | `titre` | `string` | Yes | No | | `url_image` | `string` | Yes | No | | `prix` | `number` | Yes | No | | `score_match` | `number` | No | Yes | Bind both Entities to a group named `listings_recommendations`. Each shows **Conform** when its Live SQL returns the four required columns, and the Workflow can switch Entities without changing the Content. The same pattern applies to one recommendation Entity per algorithm in a retail model. ## Saving and Publishing **Save** validates the definition — a non-empty name, at least valid field names and types, and existing member Entities — then stores the Draft. *Unsaved changes* appears in the toolbar until you save. Click **Publish** to promote the Draft to Live. The **Publish entity group** dialog accepts an optional **Commit message** describing the change. The previous Live version becomes Inactive, and a new Draft copy is created so editing can continue. Publishing requires every member to be **Conform**; a member with **No live version** blocks the publication. ## Versions Open the **Versions** panel from the toolbar rail. Each card shows the version state, its field count, the author, and the commit message when one was provided. Click a card to load that definition into the editor — the editor asks for confirmation when you have unsaved changes. Save to make the loaded definition the new Draft. Entity group editor with the Versions panel open on the right, showing a Draft card with the group name, its field count and the author ## Deleting a Group **Delete** on the listing removes the group and all its versions. The dialog warns that *Contents bound to this group will stop resolving*; this cannot be undone. Member Entities are not deleted. ## What's Next? Write the SQL and publish the Entities that join a group. Add the columns and relations your SQL needs. Consume a published Entity in a Workflow. Grant the Datagraph Entity permission to your data team.