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Constants are string values that can be defined once in a model file and referenced throughout your model using @{constant_name} syntax. Constants are resolved before other template processing (Mustache and field references) when a query executes or a link renders, making them ideal for values that need to be centrally managed and consistently applied across your model. For example:
  • Database schema names that may differ between environments
  • Common URL patterns for data links
  • Repeated string values that you want to maintain in a single location
  • Configuration values that can be dynamically referenced
Constants are also inherited by shared extension models.

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Syntax

constants:
  <constant_name>:
    value: <string_value>

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Properties

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constants
object
A map of constant definitions where each key is the constant name. Names must be unique within the model.

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Examples

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Dynamic schema reference

Use constants to reference schema names that may vary across environments. Define the constants in the model file:
Model file
constants:
  base_schema:
    value: analytics_prod
  staging_schema:
    value: analytics_staging
And then reference the constants, such as in the following view file:
View file
sql: |
  SELECT *
  FROM @{base_schema}.users
Create link patterns that include field references. Define the constants in the model file:
Model file
constants:
  google_search:
    value: "https://www.google.com/search?q=${users.country}"
  user_profile:
    value: "https://example.com/profile/${users.user_id}"
And then reference the constants in fields, such as the following dimensions:
Dimensions in a view
dimensions:
  country:
    sql: country
    link: "@{google_search}"
  user_id:
    sql: user_id
    link: "@{user_profile}"

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Reusable format patterns

Constants are often used with the format parameter on dimensions and measures. Reference a constant with @{constant_name} inside the format string (including inside conditional format branches).
For standard currency and number display, use a named format like usdcurrency_2 or percent_1 directly. Constants are most valuable for custom Excel-style patterns that appear in several fields.
Model file
constants:
  compact_time:
    value: 'm:ss "min"'
  margin_display:
    value: '#,##0.00 "bps"'
View file
measures:
  avg_duration:
    sql: '"duration_secs"'
    aggregate_type: avg
    format: "@{compact_time}"
  margin:
    sql: '"margin_bps"'
    aggregate_type: avg
    format: "@{margin_display}"
See Model constants in format strings on the format page for more detail.