# Model reference https://docs.serverpod.dev/next/concepts/lookups/model-reference Every keyword available in a Serverpod model file, and whether it applies to a `class`, `exception`, or `enum`. For how each one works, see [Working with models](https://docs.serverpod.dev/next/concepts/data-and-the-database/models.md). | **Keyword** | Note | [class](https://docs.serverpod.dev/next/concepts/data-and-the-database/models.md#class) | [exception](https://docs.serverpod.dev/next/concepts/data-and-the-database/models.md#exception) | [enum](https://docs.serverpod.dev/next/concepts/data-and-the-database/models.md#enum) | | --------------------------------------------------------------------------------------------------------------------------------------------------- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | :-------------------------------------------------------------------------------------: | :---------------------------------------------------------------------------------------------: | :-----------------------------------------------------------------------------------: | | [**values**](https://docs.serverpod.dev/next/concepts/data-and-the-database/models.md#enum) | A special key for enums with a list of all enum values. | | | ✅ | | [**serialized**](https://docs.serverpod.dev/next/concepts/data-and-the-database/models.md#enum) | Sets the mode enums are serialized in. | | | ✅ | | [**properties**](https://docs.serverpod.dev/next/concepts/data-and-the-database/models.md#enhanced-enums-with-properties) | Defines custom properties for enhanced enums. | | | ✅ | | [**immutable**](https://docs.serverpod.dev/next/concepts/data-and-the-database/models.md#immutable-classes) | Boolean flag to generate an immutable class with final fields, equals operator, and hashCode. | ✅ | | | | [**serverOnly**](https://docs.serverpod.dev/next/concepts/data-and-the-database/models.md#limiting-visibility-of-a-generated-class) | Boolean flag if code generator only should create the code for the server. | ✅ | ✅ | ✅ | | [**table**](https://docs.serverpod.dev/next/concepts/data-and-the-database/database/tables.md) | A name for the database table, enables generation of database code. | ✅ | | | | [**database**](https://docs.serverpod.dev/next/concepts/data-and-the-database/database/tables.md#choosing-where-a-table-lives) | Where a table lives: `server` (default), `client`, or `all`. | ✅ | | | | [**managedMigration**](https://docs.serverpod.dev/next/concepts/data-and-the-database/database/migrations.md#opt-out-of-migrations) | A boolean flag to opt out of the database migration system. | ✅ | | | | [**serializationDataType**](https://docs.serverpod.dev/next/concepts/data-and-the-database/database/tables.md#storing-serializable-fields-as-jsonb) | Stores serializable fields as `json` or `jsonb`. Valid on classes and on individual fields. | ✅ | | | | [**fields**](https://docs.serverpod.dev/next/concepts/data-and-the-database/models.md#class) | All fields in the generated class should be listed here. | ✅ | ✅ | | | [**type (fields)**](https://docs.serverpod.dev/next/concepts/data-and-the-database/models.md#class) | Denotes the data type for a field. | ✅ | ✅ | | | [**required**](https://docs.serverpod.dev/next/concepts/data-and-the-database/models.md#required-fields) | Makes the field required. This keyword can only be used for **nullable** fields. | ✅ | ✅ | | | [**tail**](https://docs.serverpod.dev/next/concepts/data-and-the-database/models/inheritance-and-polymorphism.md#ordering-inherited-fields) | Places the field after all normal fields of an inheritance hierarchy. Child tail fields come before parent tail fields. Not allowed on the `id` field. | ✅ | ✅ | | | [**scope**](https://docs.serverpod.dev/next/concepts/data-and-the-database/models.md#limiting-visibility-of-a-generated-class) | Denotes the scope for a field. | ✅ | | | | [**jsonKey**](https://docs.serverpod.dev/next/concepts/data-and-the-database/models.md#json-key-aliasing) | Sets a custom key name for JSON serialization and deserialization. | ✅ | | | | [**column**](https://docs.serverpod.dev/next/concepts/data-and-the-database/database/tables.md#column-name-override) | Overrides the database column name for a field. | ✅ | | | | [**persist**](https://docs.serverpod.dev/next/concepts/data-and-the-database/database/tables.md) | A boolean flag if the data should be stored in the database or not can be negated with `!persist` | ✅ | | | | [**relation**](https://docs.serverpod.dev/next/concepts/data-and-the-database/database/relations.md) | Sets a relation between model files, requires a table name to be set. | ✅ | | | | [**name**](https://docs.serverpod.dev/next/concepts/data-and-the-database/database/relations/one-to-one.md#bidirectional-relations) | Give a name to a relation to pair them. | ✅ | | | | [**parent**](https://docs.serverpod.dev/next/concepts/data-and-the-database/database/relations/one-to-one.md#with-an-id-field) | Sets the parent table on a relation. | ✅ | | | | [**field**](https://docs.serverpod.dev/next/concepts/data-and-the-database/database/relations/one-to-one.md#custom-foreign-key-field) | A manual specified foreign key field. | ✅ | | | | [**onUpdate**](https://docs.serverpod.dev/next/concepts/data-and-the-database/database/relations/referential-actions.md) | Set the referential actions when updating data in the database. | ✅ | | | | [**onDelete**](https://docs.serverpod.dev/next/concepts/data-and-the-database/database/relations/referential-actions.md) | Set the referential actions when deleting data in the database. | ✅ | | | | [**optional**](https://docs.serverpod.dev/next/concepts/data-and-the-database/database/relations/one-to-one.md#optional-relation) | A boolean flag to make a relation optional. | ✅ | | | | [**deferrable**](https://docs.serverpod.dev/next/concepts/data-and-the-database/database/relations/deferrable-constraints.md) | Make the foreign key constraint deferrable, checked after each statement unless a transaction defers it. | ✅ | | | | [**deferred**](https://docs.serverpod.dev/next/concepts/data-and-the-database/database/relations/deferrable-constraints.md) | Make the foreign key constraint deferrable and checked at commit. Mutually exclusive with **deferrable**. | ✅ | | | | [**indexes**](https://docs.serverpod.dev/next/concepts/data-and-the-database/database/indexing.md) | Create indexes on your fields / columns. | ✅ | | | | [**fields (index)**](https://docs.serverpod.dev/next/concepts/data-and-the-database/database/indexing.md) | List the fields to create the indexes on. | ✅ | | | | [**type (index)**](https://docs.serverpod.dev/next/concepts/data-and-the-database/database/indexing.md) | The type of index to create. | ✅ | | | | [**parameters (index)**](https://docs.serverpod.dev/next/concepts/data-and-the-database/database/indexing.md#vector-indexes) | Parameters for specialized index types like HNSW and IVFFLAT vector indexes. | ✅ | | | | [**distanceFunction (index)**](https://docs.serverpod.dev/next/concepts/data-and-the-database/database/indexing.md#vector-indexes) | Distance function for vector indexes. Allowed values depend on the field's vector type and index type, see [vector indexes](https://docs.serverpod.dev/next/concepts/data-and-the-database/database/indexing.md#vector-indexes). | ✅ | | | | [**operatorClass (index)**](https://docs.serverpod.dev/next/concepts/data-and-the-database/database/indexing.md#operator-classes) | Operator class for GIN indexes. | ✅ | | | | [**unique**](https://docs.serverpod.dev/next/concepts/data-and-the-database/database/indexing.md#make-fields-unique) | Creates a unique index. Also valid directly on a field, optionally scoped with `unique(per=...)`. | ✅ | | | | [**default**](https://docs.serverpod.dev/next/concepts/data-and-the-database/models.md#default-values) | Sets the default value for both the model and the database. This keyword cannot be used with **relation**. On an enum, sets the [fallback for unknown values](https://docs.serverpod.dev/next/concepts/data-and-the-database/models.md#handling-unknown-enum-values). | ✅ | ✅ | ✅ | | [**defaultModel**](https://docs.serverpod.dev/next/concepts/data-and-the-database/models.md#default-values) | Sets the default value for the model side. This keyword cannot be used with **relation**. | ✅ | ✅ | | | [**defaultPersist**](https://docs.serverpod.dev/next/concepts/data-and-the-database/models.md#default-values) | Sets the default value for the database side. This keyword cannot be used with **relation** and **!persist**. | ✅ | | | | [**extends**](https://docs.serverpod.dev/next/concepts/data-and-the-database/models/inheritance-and-polymorphism.md#extending-a-class) | Specifies a parent class or exception of the same kind to inherit from. | ✅ | ✅ | | | [**sealed**](https://docs.serverpod.dev/next/concepts/data-and-the-database/models/inheritance-and-polymorphism.md#sealed-classes) | Boolean flag to create a sealed class or exception hierarchy, enabling exhaustive type checking. | ✅ | ✅ | | ## Related - [Working with models](https://docs.serverpod.dev/next/concepts/data-and-the-database/models.md): how each keyword works, with examples. - [Dynamic fields](https://docs.serverpod.dev/next/concepts/data-and-the-database/models/dynamic-fields.md): store and transfer values whose type varies at runtime. - [Serializable exceptions](https://docs.serverpod.dev/next/concepts/endpoints-and-apis/error-handling-and-exceptions.md#serializable-exceptions): define, inherit, throw, and catch application errors. - [Database tables](https://docs.serverpod.dev/next/concepts/data-and-the-database/database/tables.md): the database-specific keywords (`table`, `relation`, `persist`, and indexing).