> ## Documentation Index
> Fetch the complete documentation index at: https://docs.pysquirrels.com/llms.txt
> Use this file to discover all available pages before exploring further.

# NumberDataSource

> Lookup table for number parameter options

Data source class for populating number parameter options from a database table or query.

This class can be imported from the `squirrels.data_sources` or the `squirrels` module.

## Constructor

Creates a `NumberDataSource` object.

```python theme={null}
def __init__(
    self, table_or_query: str, min_value_col: str, max_value_col: str, 
    *, increment_col: str | None = None, default_value_col: str | None = None, 
    id_col: str | None = None, source: SourceEnum = SourceEnum.CONNECTION, 
    user_group_col: str | None = None, parent_id_col: str | None = None, 
    connection: str | None = None
) -> None:
```

<Expandable title="arguments" defaultOpen>
  <ResponseField name="table_or_query" type="str" required>
    Either the name of the table to use, or a SQL query to run. If using a SQL query, it must start with "SELECT" (ignoring case and leading whitespaces) followed by a whitespace.

    The available tables are based on the `source` argument. If the source is `SourceEnum.CONNECTION`, then the SQL syntax is based on the underlying database from the `connection` argument. Otherwise, the SQL syntax is DuckDB SQL.
  </ResponseField>

  <ResponseField name="min_value_col" type="str" required>
    The column name for the minimum value.
  </ResponseField>

  <ResponseField name="max_value_col" type="str" required>
    The column name for the maximum value.
  </ResponseField>

  <ResponseField name="increment_col" type="str | None" default="None">
    The column name for the increment/step value. If None, defaults to 1.
  </ResponseField>

  <ResponseField name="default_value_col" type="str | None" default="None">
    The column name for the default value. If None, defaults to the minimum value.
  </ResponseField>

  <ResponseField name="source" type="SourceEnum" default="SourceEnum.CONNECTION">
    The source to fetch data from as a [SourceEnum](/references/python/data_sources/sourceenum) value.
  </ResponseField>

  <ResponseField name="user_group_col" type="str | None" default="None">
    The column name of the user group for option visibility. If None, all users will see all options.
  </ResponseField>

  <ResponseField name="parent_id_col" type="str | None" default="None">
    The column name of the parent option id for cascading.

    If None, then this parameter has no parent and its options will not be cascaded.
  </ResponseField>

  <ResponseField name="connection" type="str | None" default="None">
    Name of the connection to use. Only used if the source is `SourceEnum.CONNECTION`. Connection must be defined in `squirrels.yml` or the `connections.py` file.

    If None, uses the default connection (specified by `SQRL_CONNECTIONS__DEFAULT_NAME_USED` environment variable or 'default').
  </ResponseField>
</Expandable>

## Examples

A `NumberDataSource` object is created in the `pyconfigs/parameters.py` file. It must be created in a function decorated with the `create_from_source` factory method from [NumberParameter](/references/python/parameters/numberparameter).

### Usage example in parameters.py

```python highlight="9-21" theme={null}
from squirrels import parameters as p, data_sources as ds

@p.NumberParameter.create_from_source(
    name="top_n", 
    label="Top N Records",
    description="Number of top records to display"
)
def top_n_source():
    return ds.NumberDataSource(
        table_or_query="""
            SELECT 
                1 AS min_val,
                100 AS max_val,
                5 AS increment,
                10 AS default_val
        """,
        min_value_col="min_val",
        max_value_col="max_val",
        increment_col="increment",
        default_value_col="default_val"
    )
```

In addition, the following are some additional examples for creating a `NumberDataSource` object.

### Using a table from a specific connection

This example uses a table called "parameter\_configs" from the "config\_db" connection.

```python highlight="2,6" theme={null}
ds.NumberDataSource(
    table_or_query="parameter_configs",
    min_value_col="min_threshold",
    max_value_col="max_threshold",
    default_value_col="default_threshold",
    connection="config_db"
)
```

The connection must either be defined in `squirrels.yml` or the `connections.py` file.

### Using seeds as the data source

This example uses a seed file called "number\_config".

```python highlight="2,5" theme={null}
ds.NumberDataSource(
    table_or_query="number_config",
    min_value_col="min_value",
    max_value_col="max_value",
    source=ds.SourceEnum.SEEDS
)
```

### Enabling cascading effects with a parent parameter

In this example, the minimum, maximum, and default values are determined by the selected value of another parameter called "metric\_type".

```python highlight="5,14" theme={null}
@p.NumberParameter.create_from_source(
    name="threshold_value", 
    label="Threshold Value",
    description="The threshold for the selected metric",
    parent_name="metric_type"
)
def threshold_value_source():
    return ds.NumberDataSource(
        table_or_query="metric_thresholds",
        min_value_col="min_threshold",
        max_value_col="max_threshold",
        increment_col="step_size",
        default_value_col="default_threshold",
        parent_id_col="metric_type_id"  # Cascades based on metric_type selection
    )
```