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# Resource: Data Collections Extension

# Type: Data Collections Extension Object

# Link: https://dev.wix.com/docs/api-reference/business-solutions/cms/collection-management/data-collections-extension/data-collections-extension-object.md

## Description: Use this JSON schema to define collection schemas and optional initial data for the [data collections app extension](https://dev.wix.com/docs/build-apps/develop-your-app/extensions/backend-extensions/data-collections/about-data-collections-extensions.md).

## Schema:

```json
 Type: Data Collections Extension Object | type: DataCollectionsExtension
 Description: Use this JSON schema to define collection schemas and optional initial data for the [data collections app extension](https://dev.wix.com/docs/build-apps/develop-your-app/extensions/backend-extensions/data-collections/about-data-collections-extensions.md).
       - name: collections  | type: Array<Collection> | description: Data collections automatically added to a site when the app is installed.
           - name: idSuffix  | type: string | description: Required. Collection ID suffix. The app namespace is automatically prepended in the CMS. For example, the full ID for `my-products-1` becomes `@company/app-name/my-products-1`.
           - name: displayName  | type: string | description: Collection's display name as shown in the CMS. For example, `My First Collection`.
               - name: value  | type: string | description: 
           - name: displayField  | type: string | description: Field whose value the CMS displays to represent the collection item when referenced in a different collection.
           - name: fields  | type: Array<Field> | description: Required. Collection's field structure.
               - name: key  | type: string | description: Required. Unique identifier for the field. For example, `firstName`.
               - name: displayName  | type: string | description: Field's display name when displayed in the CMS. For example, `First Name`.
               - name: type  | type: string | description: Required. Field's data type.  Learn more about [data types in Wix Data](https://dev.wix.com/docs/rest/business-solutions/cms/data-types-in-wix-data.md).
               - name: encrypted  | type: boolean | description: Whether the field is encrypted.
               - name: description  | type: string | description: Field description.
           - name: dataPermissions  | type: DataPermissions | description: Required. Levels of permission for accessing and modifying data, defined by the lowest role needed to perform each action.
               - name: itemRead  | type: string | description: Required. Access level required to read data items.
               - name: itemInsert  | type: string | description: Required. Access level required to insert data items.
               - name: itemUpdate  | type: string | description: Required. Access level required to update data items.
               - name: itemRemove  | type: string | description: Required. Access level required to remove data items.
           - name: indexes  | type: Array<Index> | description: Indexes defined for the collection. An index is a map of a collection's data, organized according to specific fields to increase query speed.
               - name: fields  | type: Array<Field> | description: Fields for which the index is defined.  Max: 3 fields (for a unique index: 1 field)
               - name: unique  | type: boolean | description: Whether the index enforces uniqueness of values in the field for which it is defined. If `true`, the index can have only one field.  Default: `false`
           - name: initialData  | type: Array<Struct> | description: Optional initial data to populate the collection with.
               - name: fields  | type: object | description: 

```