---
title: Modularizing Queries (Python)
sidebar_label: Modularizing Queries
---

Modularization (breaking code into loosely coupled, self-contained pieces) is a common practice in software development. It should be used to improve the organization and readability of Deephaven queries in both Python and Groovy. This guide covers best practices for importing Deephaven scripts into Core+ queries from both notebooks and Git repositories.

In Python, you can import notebook scripts with the [`deephaven_enterprise.notebook`](https://docs.deephaven.io/pycoreplus/2026.01/worker/autoapi/deephaven_enterprise/notebook/index.html#module-deephaven_enterprise.notebook) package, or Git repository scripts with the [`deephaven_enterprise.controller_import`](https://docs.deephaven.io/pycoreplus/2026.01/worker/autoapi/deephaven_enterprise/controller_import/index.html#module-deephaven_enterprise.controller_import) package.

## Create a notebook to import

Create a new notebook in the [File Explorer](../interfaces/web/notebook.md#file-explorer) and add the following code:

```python
def my_method(x) -> int:
    return x + 1


class MyClass:
    def __init__(self, x):
        self.x = x

    def my_class_method(self) -> int:
        return self.x + 1
```

Save the notebook as `my_notebook.py`.

## Import the notebook

In Python, you [import other scripts](/core/docs/reference/community-questions/import-python-script/) by adding their filepath to the Python path. However, Deephaven Core+ workers have the [`deephaven_enterprise.notebook`](https://docs.deephaven.io/pycoreplus/2026.01/worker/autoapi/deephaven_enterprise/notebook/index.html#module-deephaven_enterprise.notebook) package as a more secure and convenient alternative.

Importing a Deephaven notebook only requires the [Deephaven database object](../deephaven-database/basics.md) (`db`). By default, once imported, [`meta_import`](https://docs.deephaven.io/pycoreplus/2026.01/worker/autoapi/deephaven_enterprise/notebook/index.html#deephaven_enterprise.notebook.meta_import) makes Deephaven notebooks available in the `notebook` package:

```python
from deephaven_enterprise.notebook import meta_import

meta_import(db)

# Import the whole package
import notebook.my_notebook

# Import specific variables/classes/methods
from notebook.my_notebook import my_method, MyClass
```

You may optionally change the module name that prefixes all web notebooks. The following example uses the `mynb` prefix:

```python
from deephaven_enterprise.notebook import meta_import

meta_import(db, "mynb")

# Import the whole package
import mynb.my_notebook

# Import specific variables/classes/methods
from mynb.my_notebook import my_method, MyClass
```

Packages imported this way are used the same as any other Python package. For more on Python packages in table operations, see [Python packages in Deephaven](/core/docs/how-to-guides/install-and-use-python-packages#use-python-packages-in-deephaven) and [the Python-Java boundary](/core/docs/conceptual/python-java-boundary/).

## Execute a notebook

In Python, you can also execute any other Deephaven notebook found in the [File Explorer](../interfaces/web/notebook.md#file-explorer) via [`exec_notebook`](https://docs.deephaven.io/pycoreplus/2026.01/worker/autoapi/deephaven_enterprise/notebook/index.html#deephaven_enterprise.notebook.exec_notebook). In order to do so, you must specify:

- The Deephaven database object (`db`).
- The name of the notebook, including any path prefixes. This should always be prefixed by a `/`.
- The Python directory of global variables. In most cases, this is `globals()`.

The following example attempts to execute the notebook `my_notebook.py`:

```python
from deephaven_enterprise.notebook import exec_notebook

exec_notebook(db, "/my_notebook.py", globals())
```

The following example executes `my_other_notebook.py`, which is found in the `notebooks` subdirectory:

```python
from deephaven_enterprise.notebook import exec_notebook

exec_notebook(db, "/notebooks/my_other_notebook.py", globals())
```

## Import from Git repositories

Importing scripts from an integrated Git repository uses a different approach than notebooks. Unlike notebook imports, controller imports:

- Use the [`deephaven_enterprise.controller_import`](https://docs.deephaven.io/pycoreplus/2026.01/worker/autoapi/deephaven_enterprise/controller_import/index.html#module-deephaven_enterprise.controller_import) package instead of `deephaven_enterprise.notebook`.
- Do not require passing a database object.
- Use `controller` as the default module prefix instead of `notebook`.
- Don't necessarily require script package names to match every directory.

For example, if the [`iris.scripts.repo.<repo>.paths`](../sys-admin/pq-controller/pq-controller.md#git-configuration) property is set:

```properties
iris.scripts.repo.<repo>.paths=module/deephaven
```

The package found at `module/deephaven/com/example/compute` will be imported as `com.example.compute`, leaving out the `module/deephaven` prefix:

```python
import deephaven_enterprise.controller_import

deephaven_enterprise.controller_import.meta_import()

# Import the whole package
import controller.com.example.compute as compute

# Import specific variables/classes/methods
from controller.com.example.compute import my_method, MyClass
```

You can optionally change the module prefix from the default `controller`. The following example uses the `git` prefix:

```python
import deephaven_enterprise.controller_import

deephaven_enterprise.controller_import.meta_import("git")

# Import with custom prefix
import git.com.example.compute as compute
from git.com.example.compute import my_method, MyClass
```

To execute a single Python file from the controller without importing it as a module:

```python
import deephaven_enterprise.controller_import

deephaven_enterprise.controller_import.exec_script("com/example/script_to_execute.py")
```

## Related documentation

- [Code Studio](../interfaces/web/code-studio.md)
- [Integrate Git with Deephaven](./git.md)
- [The Python-Java boundary](/core/docs/conceptual/python-java-boundary/)
- [Notebook imports Pydoc](https://docs.deephaven.io/pycoreplus/2026.01/worker/autoapi/deephaven_enterprise/notebook/index.html#module-deephaven_enterprise.notebook)
- [Controller imports Pydoc](https://docs.deephaven.io/pycoreplus/2026.01/worker/autoapi/deephaven_enterprise/controller_import/index.html#module-deephaven_enterprise.controller_import)