Best practice
Catching missing tables and stale references before a dashboard breaks
Why does a model look fine until someone runs it?
The rule
Trust: InferredCheck every reference before anyone runs it: each table, field and explore that a model or dashboard names must exist. A model can read fine and still point at tables that are not there. Nothing fails until someone opens the chart, often long after the change that broke it.
Why it matters
Trust: InferredA LookML file can reference views, fields and explores that no file declares. Nothing fails until someone runs the query, and a reader of the repo cannot tell what those references meant.
Missing views remove the evidence needed to check grain and keys. Stale field names fail at query time for whoever clicks the tile, often long after the change that broke them.
How to check your own model
Trust: Suggested- List every table, view and explore the model names, including derived tables it reads by name, and confirm each one exists.
- Validate dashboards against every model that includes them.
- Keep file names aligned with the names they declare, or note the mapping at the top of the file.
- Run the check in your build (Looker's validator,
dbt parse, a query against the catalog) so a broken reference stops the release.
A safer shape
Check raw tables in the catalog, model objects in the model
Trust: SuggestedTwo kinds of reference break differently. Raw tables the model reads directly can be checked against the warehouse catalog before each release. Views and derived tables defined in the model itself are checked by the model's own validator; a missing LookML view is not a missing table.
Show the suggested SQL: raw tables the model reads
WITH expected AS ( SELECT 'users' AS table_name UNION ALL SELECT 'user_transactions' UNION ALL SELECT 'subscriptions' UNION ALL SELECT 'messages' UNION ALL SELECT 'propositions')SELECT e.table_nameFROM expected AS eLEFT JOIN information_schema.tables AS t ON t.table_name = e.table_name AND t.table_schema = current_schema()WHERE t.table_name IS NULLWhere it shows up in real projects 4
sessions: Built on four views that are not here
Trust: Source-definedThe sessions derived table reads sessions_basic, sessions_geo, sessions_last_page and sessions_technology by SQL_TABLE_NAME. None is declared in the repo.
Source: user_sessions.view.lookml L69-89
t.dvce_ismobile, t.dvce_screenwidth, t.dvce_screenheight FROM ${sessions_basic.SQL_TABLE_NAME} AS s LEFT JOIN ${sessions_geo.SQL_TABLE_NAME} AS g ON s.app_id = g.app_id AND s.domain_userid = g.domain_userid AND s.domain_sessionidx = g.domain_sessionidx LEFT JOIN ${TABLE}.sessions_landing_page AS l ON s.app_id = l.app_id AND s.domain_userid = l.domain_userid AND s.domain_sessionidx = l.domain_sessionidx LEFT JOIN ${sessions_last_page.SQL_TABLE_NAME} AS l2 ON s.app_id = l2.app_id AND s.domain_userid = l2.domain_userid AND s.domain_sessionidx = l2.domain_sessionidx LEFT JOIN ${TABLE}.sessions_source AS s2 ON s.app_id = s2.app_id AND s.domain_userid = s2.domain_userid AND s.domain_sessionidx = s2.domain_sessionidx LEFT JOIN ${sessions_technology.SQL_TABLE_NAME} AS t ON s.app_id = t.app_id AND s.domain_userid = t.domain_userid AND s.domain_sessionidx = t.domain_sessionidx sql_trigger_value: SELECT COUNT(*) FROM ${TABLE}.events_atomic distkey: domain_userid sortkeys:dating-platform, user_sessions.view.lookml, lines 69-89
enterprise: Explores based on missing views
Trust: Source-definedThe tests explore is based on user_metrics, and several joins target users. Neither view exists in the repo.
Source: enterprise.model.lookml L55-61
joins: - join: propositions sql_on: propositions.proposition_template_id = date_ideas.id- explore: tests view: user_metrics label: Test Metrics joins: - join: user_experiment_buckets sql_on: user_metrics.id = user_experiment_buckets.user_id fields: [] - join: tests from: experiments sql_foreign_key: user_experiment_buckets.experiment_iddating-platform, enterprise.model.lookml, lines 55-61
business dashboards: Tiles on explores no model declares
Trust: Source-definedBusiness overview tiles query a users explore. No model in the repo declares one, so these tiles cannot run as written.
Source: company_overview.dashboard.lookml L62-73
y_axis_min: null y_axis_max: null hide_points: true - name: users_map title: Where are Users? type: looker_geo_coordinates explore: users map: usa dimensions: - users.zipcode measures: - users.count limit: null width: null height: null - name: users_by_orientation title: Users by Orientation type: looker_piedating-platform, company_overview.dashboard.lookml, lines 62-73
visitors: Drill sets that point nowhere
Trust: Source-definedindividual_detail lists referer_host and number_of_events, which the view does not declare. A drill on visitor count fails or shows fewer columns than intended.
Source: guests.view.lookml L239-255
- referer_medium_count - referer_source_count - referer_term_count individual_detail: - user_id - first_touch - last_touch - referer_medium - referer_source - referer_host - referer_url_host - referer_url_path - campaign_medium - campaign_source - campaign_name - landing_page_url - number_of_sessions - number_of_events - session_stream - event_streamdating-platform, guests.view.lookml, lines 239-255