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

# Identifiers

> Explore the role of identifiers in our semantic model and how they facilitate comprehensive data analysis.

<Warning>
  Connecting to databases other than Google Analytics requires an Enterprise
  plan. [Contact Sales](mailto:hello@findly.ai) for details.
</Warning>

## What are Identifiers?

Identifiers represent real-world concepts within a business context, like customers, transactions, or ad campaigns. Analyses frequently revolve around specific identifiers, for example, in customer churn analysis or annual recurring revenue modeling. In semantic models, these identifiers are represented by ID columns, which act as join keys to link different semantic models within the semantic graph.

Identifiers offer a clear structure to the underlying data, enabling more coherent and insightful analysis.

## How to Define Identifiers

Every identifier requires a name and type. The name can reference the key column name from the data table, or function as an alias with the column name referenced in the expr parameter.

<CardGroup cols={2}>
  <Card title="Name">
    Refers to the key column name from the underlying data table or serves as an
    alias if the actual column name is specified in the `expr` parameter.
  </Card>

  <Card title="Type">
    Defines the identifier's role in join logic and determines the join type
    (e.g., Primary, Foreign, Unique).
  </Card>

  <Card title="Expression (optional)">
    Specifies the underlying column for the identifier. If omitted, it defaults
    to the identifier's name.
  </Card>
</CardGroup>

## How to create and edit an identifier

In the [Catalog](https://dashboard.findly.ai/app/catalog) section, select the table for which you want to set up an identifier. Then, navigate to the `Entities` tab.

<img src="https://mintcdn.com/findly/1xEknXya6BSPSEwM/docs/app/catalog/assets/screen-table-views.png?fit=max&auto=format&n=1xEknXya6BSPSEwM&q=85&s=a890f3869b009ddc9184024f89fe2f4e" width="1280" height="640" data-path="docs/app/catalog/assets/screen-table-views.png" />

<img src="https://mintcdn.com/findly/1xEknXya6BSPSEwM/docs/app/catalog/assets/screen-identifiers.png?fit=max&auto=format&n=1xEknXya6BSPSEwM&q=85&s=d84694e468af03530b3b5d14d40dd17e" width="1280" height="640" data-path="docs/app/catalog/assets/screen-identifiers.png" />

<img src="https://mintcdn.com/findly/1xEknXya6BSPSEwM/docs/app/catalog/assets/screen-identifiers-form.png?fit=max&auto=format&n=1xEknXya6BSPSEwM&q=85&s=b5a2304dd6bd3c9aa05ed99640c70122" width="1280" height="640" data-path="docs/app/catalog/assets/screen-identifiers-form.png" />

## Specification for Identifiers

Identifiers are defined using the following parameters:

```yaml theme={null}
identifiers:
  - name: [name]
    type: [Primary or Natural or Foreign or Unique]
    description: [description of the field or role]
    expr: [column name or expression, defaults to the name if not provided]
```

For example, in a semantic model for sales data, identifiers could be defined as follows:

```yaml theme={null}
identifiers:
  - name: transaction
    type: primary
    expr: id_transaction
  - name: order
    type: foreign
    expr: id_order
  - name: user
    type: foreign
    expr: substring(id_order from 2)
```

## Identifier Types and Join Logic

Findly uses different join logic based on the identifier type:

<Tabs>
  <Tab title="Primary">
    A primary identifier indicates that each row in the table represents a
    unique record, encompassing all records in the data platform.
  </Tab>

  <Tab title="Unique">
    A unique key ensures one record per row in the table. It might represent a
    subset of records in the data warehouse and can include nulls.
  </Tab>

  <Tab title="Foreign">
    Foreign keys can have none, one, or multiple instances of the same record
    and may include null values.
  </Tab>
</Tabs>

<br />

<Info>
  Identifiers (join keys) within a semantic model are identified by their name.
  Names must be unique within a specific model but can be reused across
  different models.
</Info>

## Utilizing Identifiers as Dimensions

Identifiers can also serve as dimensions, allowing metrics to be aggregated to the identifier's level of granularity.

<Accordion title="FAQ: Can identifiers be utilized in conjunction with dimensions?">
  Absolutely! Identifiers can be used as dimensions, enabling the aggregation of
  metrics at the granularity of that particular identifier.
</Accordion>

## Wrapping up

Identifiers are foundational elements that establish relationships and ensure seamless data analysis. By understanding identifiers and their applications, businesses can derive richer insights and make more informed data-driven decisions.