sample.schema.yml

# This configuration file specifies constraints that should (ideally)
# be true about your data models. The constraints can be tested using
# the `dbt test --schema` command. When that command is executed, dbt
# will compile this schema.yml file to a series of SQL statements and
# validate that the specified constraints hold against your data.

# A dbt project can contain any number of schema.yml files. Moreover,
# schema.yml files can be placed anywhere within the `models` directory
# of your dbt project.

# There are four types of schema validations:
#  - Not null
#  - Unique
#  - Referential integrity
#  - Field in list of accepted values

# A schema.yml file should specify constraints for one or more models.
# These constraints should adhere to the following structure:

# [model-name]:
#     constraints:
#         not_null:
#             - [field or expression]
#             - [field or expression]
#             ...
# 
#         unique:
#             - [field or expression]
#             - [field or expression]
#             ...
# 
#         relationships:
#             - {from: [field], to: [other-model], field: [other-field]}
#             ...
# 
#         accepted_values:
#             - {field: [field or expression], values: ['valid', 'values', 'here']}
#             ...
#
# Below is an example of some schema constraints defined for fictitious models.
#

people:
  constraints:
    # check number of times these fields are null (should be 0)
    not_null:
      - id
      - account_id
      - name

    # count number of non-unique `id` fields (should be 0)
    unique:
      - id

    # count number of rows where `people.account_id` points to a nonexistent `accounts.id` (should be 0)
    # Note: the 'accounts' model needs to be `ref`d here
    relationships:
      - {from: account_id, to: ref('accounts'), field: id}

accounts:
  constraints:
    # count number of rows where a value is not in the given accepted values
    accepted_values:
      - {field: tier, values: ['paid', 'free']}

    not_null:
      - id
      - domain

    unique:
      - id