Data Modeling

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Moose Data Models serve as the foundational blueprint for your application's data architecture. By defining the schema and structure of your data, Moose derives the underlying infrastructure to needed to support the data typed to the schema. This includes REST APIs for data ingestion, Redpanda topics for streaming, and ClickHouse tables for storage.

These models can be imported into various parts of your application, allowing you to utilize these strongly-typed data objects in transformations, APIs, and custom logic, so you can ensure consistent and reliable data pipelines without needing to maintain repetitive boilerplate code and manage the complexities of data infrastructure.

app/datamodels/MyDataModel.ts

import { Key } from "moose-lib";
 
export interface MyDataModel {
  primaryKey: Key<string>;
  someString: string;
  someNumber: number;
  someBoolean: boolean;
  someDate: Date;
  someArray: string[];
}

app/datamodels/MyDataModel.py

from moose_lib import Key, moose_data_model
from dataclasses import dataclass
from datetime import datetime
 
@moose_data_model
@dataclass
class MyDataModel:
    primary_key: Key[str]
    some_string: str
    some_number: int
    some_boolean: bool
    some_date: datetime
    some_list: list[str]

Quick Start

Data Models are defined in the /datamodels directory of your Moose application. This folder is automatically created when you initialize a new Moose application.

To create a new Data Model, either create a new file in the /datamodels directory or run the following command:

Terminal

npx moose-cli data-model init MyDataModel --sample <PATH_TO_SAMPLE_DATA>

The CLI will create a new file in the /datamodels directory with the name of the Data Model:

- MyDataModel.ts

Automatically Infer Data Model

If you have a .json or .csv file with sample data representing the structure of the data you want to ingest, you can use the --sample flag. The CLI will then infer the Data Model schema from the provided file and create the Data Model for you.

Data Model Definition

Data Models are written as TypeScript interfaces. To have Moose recognize your Data Model, you must export them from a .ts file. For example:

datamodels/models.ts

import { Key } from "@514labs/moose-lib";
 
export interface MyFirstDataModel {
  primaryKey: Key<string>;
  someString: string;
  someNumber: number;
  someBoolean: boolean; 
  someDate: Date;
  someArray: string[];
  someOptionalString?: string; // Optional fields are marked with a `?`
}

Note

You can define multiple data models in the same file. Each exported interface is automatically recognized by Moose.

Data Models are defined as Python dataclasses using the @dataclass decorator. To ensure Moose automatically detects and registers the dataclass as a Data Model, apply the @moose_data_model decorator to your dataclass:

Importing the moose_data_model decorator:

Import the @moose_data_model decorator from the moose_lib package.

datamodels/models.py

from moose_lib import Key, moose_data_model
from dataclasses import dataclass
from typing import List
from datetime import datetime
 
@moose_data_model
@dataclass
class MyFirstDataModel:
    primary_key: Key[str]
    some_string: str
    some_number: int
    some_boolean: bool
    some_date: datetime
    some_array: List[str]
    some_optional_string: Optional[str]

Note

You can define multiple data models in the same file. Each dataclass decorated with @moose_data_model is automatically recognized by Moose.

Basic Usage and Examples

Below you will find several examples showing the different ways you can define Data Models.

Basic Data Model

sample_data.json

{
  "example_UUID": "123e4567-e89b-12d3-a456-426614174000",
  "example_string": "string",
  "example_number": 123,
  "example_boolean": true,
  "example_array": [1, 2, 3]
}

datamodels/models.ts

import { Key } from "@514labs/moose-lib";
 
export interface BasicDataModel {
  example_UUID: Key<string>;
  example_string: string;
  example_number: number;
  example_boolean: boolean;
  example_array: number[];
}

datamodels/models.py

from dataclasses import dataclass
from moose_lib import Key, moose_data_model
 
@moose_data_model
@dataclass
class BasicDataModel:
    example_UUID: Key[str]
    example_string: str
    example_number: int
    example_boolean: bool
    example_array: list[int]

Optional Fields

sample.json

[
  {
    "example_UUID": "123e4567-e89b-12d3-a456-426614174000",
    "example_string": "string",
    "example_number": 123,
    "example_boolean": true,
    "example_array": [1, 2, 3],
    "example_optional_string": "optional"
  },
  {
    "example_UUID": "123e4567-e89b-12d3-a456-426614174000",
    "example_string": "string",
    "example_number": 123,
    "example_boolean": true,
    "example_array": [1, 2, 3]
  }
]

datamodels/models.ts

import { Key } from "@514labs/moose-lib";
 
export interface DataModelWithOptionalField {
  example_UUID: Key<string>;
  example_string: string;
  example_number: number;
  example_boolean: boolean;
  example_array: number[];
  example_optional_string?: string; // Use the `?` operator to mark a field as optional
}

datamodels/models.py

from dataclasses import dataclass
from typing import Optional
from moose_lib import Key, moose_data_model
 
@moose_data_model
@dataclass
class DataModelWithOptionalField:
    example_UUID: Key[str]
    example_string: str
    example_number: int
    example_boolean: bool
    example_array: list[int]
    example_optional_string: Optional[str] # Use the Optional type

Nested Fields

sample.json

{
  "example_UUID": "123e4567-e89b-12d3-a456-426614174000",
  "example_string": "string",
  "example_number": 123,
  "example_boolean": true,
  "example_array": [1, 2, 3],
  "example_nested_object": {
    "example_nested_number": 456,
    "example_nested_boolean": true,
    "example_nested_array": [4, 5, 6]
  }
}

datamodels/models.ts

import { Key } from "@514labs/moose-lib";
 
// Define the nested object interface separately
interface NestedObject {
  example_nested_number: number;
  example_nested_boolean: boolean;
  example_nested_array: number[];
}
 
export interface DataModelWithNestedObject {
  example_UUID: Key<string>;
  example_string: string;
  example_number: number;
  example_boolean: boolean;
  example_array: number[]; 
  example_nested_object: NestedObject; // Reference nested object interface
}

datamodels/models.py

from moose_lib import Key, moose_data_model
from dataclasses import dataclass
 
@dataclass
class ExampleNestedObject:
    example_nested_number: int
    example_nested_boolean: bool
    example_nested_array: list[int]
 
@moose_data_model  # Only register the outer dataclass
@dataclass
class DataModelWithNestedObject:
    example_UUID: Key[str]
    example_string: str
    example_number: int
    example_boolean: bool
    example_array: list[int]
    example_nested_object: ExampleNestedObject # Use the nested dataclass instead of a dict

Using Enum in Data Models

Moose supports the use of Enums in Data Models:

datamodels/DataModelWithEnum.ts

import { Key } from "@514labs/moose-lib";
 
enum MyEnum {
  VALUE_1 = "value1",
  VALUE_2 = "value2",
}
 
export interface DataModelWithEnum {
  example_UUID: Key<string>;
  example_enum: MyEnum;
}

datamodels/DataModelWithEnum.py

from moose_lib import Key, moose_data_model
from enum import Enum
 
class MyEnum(Enum):
    VALUE_1 = "value1"
    VALUE_2 = "value2"
 
@moose_data_model
@dataclass
class DataModelWithEnum:
    example_UUID: Key[str]
    example_enum: MyEnum

Inherritance

Moose supports the use of inheritance in Data Models. This allows you to create a base Data Model and extend it with additional fields:

datamodels/models.ts

import { Key } from "@514labs/moose-lib";
 
export interface BaseDataModel {
  example_UUID: Key<string>;
}
 
export interface ExtendedDataModel extends BaseDataModel {
  example_string: string;
}
 
// Schema of ExtendedDataModel:
// {
//   "example_UUID": "123e4567-e89b-12d3-a456-426614174000",
//   "example_string": "string"
// }

Inheritance is not supported in Python

Inheritance is not supported in Python. Instead, you can use composition to achieve similar functionality. Support for inheritance is in the works.

datamodels/models.py

from dataclasses import dataclass
from moose_lib import Key, moose_data_model
from typing import Optional
 
@dataclass
class BaseData:
    # The fields that might have otherwise lived in a base class
    id: Key[str]
    created_at: str
 
@moose_data_model
@dataclass
class CompositeDataModel:
    # Use composition by embedding BaseData
    base_data: BaseData
 
    # The "extended" fields
    user_name: str
    email: Optional[str] = None

Field Types

The schema defines the names and data types of the properties in your Data Model. Moose uses this schema to automatically set up the data infrastructure, ensuring that only data conforming to the schema can be ingested, buffered, and stored.

Key Type

The Key[T: (str, int)]Key<T> type is specific to Moose and is used to define a primary key (opens in a new tab) in the OLAP storage table for your Data Model. If your Data Model requires a composite key, you can apply the Key type to multiple columns.

Key Type is Required

If you do not specify a Key type, you must set up a DataModelConfig to specify the properties that will be used for the order_by_fields. Learn more in the configuration section below.

Supported Field Types

The table below shows the supported field types for your Data Model and the mapping for how Moose will store them in ClickHouse:

Clickhouse	TypeScript	Moose
String	string	✅
Boolean	boolean	✅
Int64	number	✅
Int256	BigInt	❌
Float64	number	✅
Decimal	number	✅
DateTime	Date	✅
Json	Object	✅
Bytes	bytes	❌
Enum	Enum	✅
Array	Array	✅
nullable	nullable	✅

Disclaimer

All TypeScript number types are mapped to Float64

Clickhouse	Python	Moose
String	str	✅
Boolean	bool	✅
Int64	int	✅
Int256	int	❌
Float64	float	✅
Decimal	float	✅
DateTime	datetime.datetime	✅
Json	dict	❌
Bytes	bytes	❌
Array	list[]	✅
nullable	Optional[T]	✅

Use Nested Dataclasses Instead of dicts

Moose does not support using dict types for Data Models. Instead, use nested dataclasses to define your Data Model.

Ingestion and Storage Configuration

Moose provides sensible defaults for ingesting and storing your data, but you can override these behaviors by exporting a DataModelConfig:

Default Configuration

When you do not create a custom DataModelConfig, Moose will use the following defaults:

Ingestion expects a single JSON object per request.
A ClickHouse table is automatically created with no explicit ORDER BY fields (the Data Model is defined with a Key).
Deduplication is disabled.

datamodels/DefaultDataModel.ts

import { Key, DataModelConfig, IngestionFormat } from "@514labs/moose-lib";
 
export interface DefaultDataModel {
  id: Key<string>;
  value: number;
  timestamp: Date;
}
 
// If you omit this config entirely, Moose will still behave the same way as just exporting the DefaultDataModel interface:
// - single JSON ingestion
// - storage enabled
// - deduplication disabled
// - no ORDER BY fields
export const DefaultDataModelConfig: DataModelConfig<DefaultDataModel> = {
  ingestion: {
    format: IngestionFormat.JSON,
  },
  storage: {
    enabled: true,
    deduplicate: false,
  },
};

datamodels/DefaultDataModel.py

from dataclasses import dataclass
from moose_lib import Key, moose_data_model, DataModelConfig, IngestionConfig, IngestionFormat, StorageConfig
 
# If you omit this config entirely, Moose will still behave the same way as just defining the 
# DefaultDataModel dataclass without any config arguments supplied to the @moose_data_model decorator:
# - single JSON ingestion
# - storage enabled
# - no ORDER BY fields
default_config = DataModelConfig(
    ingestion=IngestionConfig(
        format=IngestionFormat.JSON
    ),
    storage=StorageConfig(enabled=True)
)
 
## default_config is not necessary if you don't need to customize ingestion or storage
@moose_data_model(default_config)
@dataclass
class DefaultDataModel:
    id: Key[str]
    value: float
    timestamp: datetime

Enabling Batch Ingestion

Batch ingestion allows you to send multiple records in a single request by setting the ingestion parameter to IngestionFormat.JSON_ARRAY. Instead of sending individual JSON objects, you can send an array of objects that match your data model schema:

datamodels/models.ts

import {
  Key,
  DataModelConfig,
  IngestionFormat
} from "@514labs/moose-lib";
 
export interface BatchDataModel {
  batchId: Key<string>;
  metric: number;
}
 
export const BatchDataModelConfig: DataModelConfig<BatchDataModel> = {
  ingestion: {
    format: IngestionFormat.JSON_ARRAY // accept an array of JSON objects in the request
  }
};

datamodels/models.py

from dataclasses import dataclass
from moose_lib import (
    Key,
    moose_data_model,
    DataModelConfig,
    IngestionConfig,
    IngestionFormat
)
 
@moose_data_model(
    DataModelConfig(
        ingestion=IngestionConfig(
            format=IngestionFormat.JSON_ARRAY
        )
    )
)
@dataclass
class BatchDataModel:
    batch_id: Key[str]
    metric: float

Disabling Storage

If you want to process upstream data using an ETL approach—cleaning it with a Streaming function before landing it in OLAP storage—disable storage with the storage parameter. This prevents Moose from creating a table in ClickHouse while still provisioning the ingestion endpoint and streaming topic for further processing.

datamodels/NoStorageModel.ts

import { Key, DataModelConfig, StorageConfig } from "@514labs/moose-lib";
 
export interface NoStorageModel {
  id: Key<string>;
  data: string;
}
 
export const NoStorageConfig: DataModelConfig<NoStorageModel> = {
  storage: {
    enabled: false // no table creation in OLAP storage
  }
};

datamodels/NoStorageModel.py

from dataclasses import dataclass
from moose_lib import (
    Key,
    moose_data_model,
    DataModelConfig,
    StorageConfig
)
 
no_storage_config = DataModelConfig(
    storage=StorageConfig(enabled=False)  # no table creation in OLAP storage
)
 
@moose_data_model(no_storage_config)
@dataclass
class NoStorageModel:
    id: Key[str]
    data: str

Setting Up Deduplication

Use the deduplicate parameter to enable deduplication. This will remove duplicate data from the table with the same order_by_fields.

Disclaimer

NOTE: There are significant caveats when enabling deduplication. This feature uses ClickHouse's ReplacingMergeTree engine for eventual deduplication, meaning that duplicate records may not be removed immediately—this process can take days or, in some cases, might not occur at all. Be aware that turning on this property changes the underlying ClickHouse engine. For more details, please see the ClickHouse documentation on ReplacingMergeTree deduplication: https://clickhouse.com/docs/en/engines/table-engines/mergetree-family/replacingmergetree (opens in a new tab)

Important

You must use the order_by_fields parameter to specify the columns that will be used for deduplication. Moose will preserve the latest inserted row using the order_by_fields as the sort key.

datamodels/DeduplicatedModel.ts

import { DataModelConfig, StorageConfig } from "@514labs/moose-lib";
 
export interface DeduplicatedModel {
  timestamp: Date;
  data: string;
}
 
export const DeduplicatedModelConfig: DataModelConfig<DeduplicatedModel> = {
  storage: { 
    enabled: true, 
    deduplicate: true, // uses ReplacingMergeTree Clickhouse engine, which preserves the highest priority row based on the order_by_fields
    order_by_fields: ["timestamp"] // deduplication is based on the timestamp column
  }
};

datamodels/DeduplicatedModel.py

from dataclasses import dataclass
from moose_lib import (
    moose_data_model,
    DataModelConfig, 
    StorageConfig
)
 
deduplicated_config = DataModelConfig(
    storage=StorageConfig(
        enabled=True,
        deduplicate=True,
        order_by_fields=["timestamp"]
    )
)
 
@moose_data_model(deduplicated_config)
@dataclass
class DeduplicatedModel:
    timestamp: datetime
    data: str

Specifying `ORDER BY` Fields

The order_by_fields parameter determines how data is physically sorted and indexed in ClickHouse. When you specify order_by_fields, ClickHouse will:

Sort data by these columns on disk, enabling efficient range queries
Create sparse primary indexes on these columns to accelerate data lookups
Use these columns as the sorting key in the underlying MergeTree engine

If you don't have a Key field in your model, specifying order_by_fields is required to ensure your data has proper indexing. Choose columns that you frequently filter or sort by in your queries. Common choices include timestamps, categorical fields, or business identifiers.

datamodels/OrderedModel.ts

import { Key, DataModelConfig, StorageConfig } from "@514labs/moose-lib";
 
export interface OrderedModel {
  primaryKey: Key<string>;
  value: number;
  createdAt: Date;
}
 
export const OrderedModelConfig: DataModelConfig<OrderedModel> = {
  storage: {
    enabled: true,
    order_by_fields: ["createdAt"] // optimize queries by creation date
  }
};

datamodels/OrderedModel.py

from dataclasses import dataclass
from datetime import datetime
from moose_lib import (
    Key,
    moose_data_model,
    DataModelConfig,
    StorageConfig
)
 
ordered_config = DataModelConfig(
    storage=StorageConfig(
        enabled=True,
        order_by_fields=["some_date", "some_string"]  # optimize queries by some_date and some_string
    )
)
 
@moose_data_model(ordered_config)
@dataclass
class OrderedModel:
    some_string: str
    some_number: float
    some_date: datetime

Combining Customizations

You can mix ingestion and storage settings in one config. Below is a complete example that:

Accepts batch JSON.
Disables storage (e.g., ephemeral or streaming-only use case).
Includes an explicit ORDER BY for the scenario where you may enable storage later.

datamodels/models.ts

import {
  Key,
  DataModelConfig,
  IngestionFormat,
  StorageConfig,
  IngestionConfig,
} from "@514labs/moose-lib";
 
export interface HybridModel {
  id: string;
  score: number;
  eventTime: Date;
}
 
export const HybridConfig: DataModelConfig<HybridModel> = {
  ingestion: {
    format: IngestionFormat.JSON_ARRAY
  },
  storage: {
    enabled: false,         // disable table creation now ...
  }
};

datamodels/models.py

from dataclasses import dataclass
from datetime import datetime
from moose_lib import (
    Key,
    moose_data_model,
    DataModelConfig,
    IngestionConfig,
    IngestionFormat,
    StorageConfig
)
 
hybrid_config = DataModelConfig(
    ingestion=IngestionConfig(format=IngestionFormat.JSON_ARRAY),
    storage=StorageConfig(
        enabled=False,  # table creation off
    )
)
 
@moose_data_model(hybrid_config)
@dataclass
class HybridModel:
    id: str
    score: float
    event_time: datetime

Batch Load Data Ingesting Data

Data Modeling

Viewing typescript

switch to python

Quick Start

Data Model Definition

Basic Usage and Examples

Basic Data Model

Optional Fields

Nested Fields

Using Enum in Data Models

Inherritance

Field Types

Key Type

Supported Field Types

Ingestion and Storage Configuration

Default Configuration

Enabling Batch Ingestion

Disabling Storage

Setting Up Deduplication

Specifying ORDER BY Fields

Combining Customizations

Specifying `ORDER BY` Fields