> ## 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.

# TextDataSource

> Lookup table for text parameter options

Data source class for populating text 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 `TextDataSource` object.

```python theme={null}
def __init__(
    self, table_or_query: str, default_text_col: str, 
    *, 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="default_text_col" type="str" required>
    The column name for the default text 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 `TextDataSource` 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 [TextParameter](/references/python/parameters/textparameter).

### Usage example in parameters.py

```python highlight="9-14" theme={null}
from squirrels import parameters as p, data_sources as ds

@p.TextParameter.create_from_source(
    name="search_query", 
    label="Search Query",
    description="Enter search terms"
)
def search_query_source():
    return ds.TextDataSource(
        table_or_query="""
            SELECT 'product' AS default_search
        """,
        default_text_col="default_search"
    )
```

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

### Using a table from a specific connection

This example uses a table called "default\_values" from the "config\_db" connection.

```python highlight="2,4" theme={null}
ds.TextDataSource(
    table_or_query="default_values",
    default_text_col="search_term",
    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 "text\_defaults".

```python highlight="2,4" theme={null}
ds.TextDataSource(
    table_or_query="text_defaults",
    default_text_col="default_value",
    source=ds.SourceEnum.SEEDS
)
```

### Enabling cascading effects with a parent parameter

In this example, the default text value is determined by the selected value of another parameter called "template\_type".

```python highlight="5,16" theme={null}
@p.TextParameter.create_from_source(
    name="message_template", 
    label="Message Template",
    description="The default message template for the selected type",
    parent_name="template_type"
)
def message_template_source():
    return ds.TextDataSource(
        table_or_query="""
            SELECT 
                template_type_id,
                default_message
            FROM message_templates
        """,
        default_text_col="default_message",
        parent_id_col="template_type_id"  # Cascades based on template_type selection
    )
```