Merge pull request #389 from fishtown-analytics/development

merge dev into master so docs are up-to-date

CHANGELOG.md

@@ -20,6 +20,7 @@
 
 ### Changes
 
+- Changed: different syntax for "relationships" schema tests ([#339](https://github.com/fishtown-analytics/dbt/pull/339))
 - Added: `already_exists` context function ([#372](https://github.com/fishtown-analytics/dbt/pull/372))
 - Graph refactor: fix common issues with load order ([#292](https://github.com/fishtown-analytics/dbt/pull/292))
 - Graph refactor: multiple references to an ephemeral models should share a CTE ([#316](https://github.com/fishtown-analytics/dbt/pull/316))

dbt/exceptions.py

@@ -63,7 +63,7 @@ def ref_invalid_args(model, args):
 
 
 def ref_bad_context(model, target_model_name, target_model_package):
- ref_string = "{{ ref('" + target_model_name + "}') }}}}"
+ ref_string = "{{ ref('" + target_model_name + "') }}"
 
  if target_model_package is not None:
  ref_string = ("{{ ref('" + target_model_package +

docs/guide/context-variables.md

@@ -49,6 +49,97 @@ Besides `{{ this }}`, there are a number of other helpful context variables avai
 | invocation_id | A UUID generated for this dbt run (useful for auditing) |
 
 
+## adapter
+
+`adapter` makes available some internal dbt functions that are useful for implementing custom logic in your
+dbt models. For example, you could write your own advanced incremental model using code like:
+
+```sql
+-- some_model.sql
+
+select * from {{ref('raw_table')}}
+
+{% if adapter.already_exists(this.schema, this.name) %}
+ where id > (select max(id) from {{this}})
+{% endif %}
+```
+
+Functions are documented below.
+
+---
+
+#### adapter.already_exists
+
+__Args__:
+
+ * `schema`: The schema to test
+ * `table`: The relation to look for
+
+Returns true if a relation named like `table` exists in schema `schema`, false otherwise.
+
+__Example__:
+```sql
+select * from {{ref('raw_table')}}
+
+{% if adapter.already_exists(this.schema, this.name) %}
+ where id > (select max(id) from {{this}})
+{% endif %}
+```
+
+([Source on Github](https://github.com/fishtown-analytics/dbt/blob/v0.8.0/dbt/wrapper.py#L165-L167))
+
+---
+
+#### adapter.get_columns_in_table
+
+__Args__:
+
+ * `schema_name`: The schema to test
+ * `table_name`: The relation from which to select columns
+
+Returns a list of [Columns](https://github.com/fishtown-analytics/dbt/blob/v0.8.0/dbt/schema.py#L37) in a table. Useful for writing `INSERT ... SELECT` queries.
+
+__Example__:
+
+```sql
+{% set dest_columns = adapter.get_columns_in_table(schema, identifier) %}
+{% set dest_cols_csv = dest_columns | map(attribute='quoted') | join(', ') %}
+
+insert into {{ this }} ({{ dest_cols_csv }}) (
+ select {{ dest_cols_csv }}
+ from {{ref('another_table')}}
+);
+```
+
+([Source on Github](https://github.com/fishtown-analytics/dbt/blob/v0.8.0/dbt/wrapper.py#L169-L171))
+
+---
+
+#### adapter.get_missing_columns
+
+__Args__:
+
+ * `from_schema`: The schema for the `from_table`
+ * `from_table`: The `from_table` to check for differences
+ * `to_schema`: The schema for the `to_table`
+ * `to_table`: The `to_table` to check for differences
+
+Returns the set of [Columns](https://github.com/fishtown-analytics/dbt/blob/v0.8.0/dbt/schema.py#L37) that is the difference of the columns in the `from_table`
+and the columns in the `to_table`, i.e. (`set(from_table.columns) - set(to_table.columns)`).
+Useful for detecting new columns in a source table.
+
+__Example__:
+
+```sql
+{% for col in adapter.get_missing_columns(this.schema, 'source_table', this.schema, this.name) %}
+ alter table {{this}} add column "{{col.name}}" {{col.data_type}};
+{% endfor %}
+```
+
+([Source on Github](https://github.com/fishtown-analytics/dbt/blob/v0.8.0/dbt/wrapper.py#L173-L177))
+
+---
+
 ## Arbitrary configuration variables
 
 Variables can be passed from your `dbt_project.yml` file into models during compilation.

docs/guide/testing.md

@@ -44,7 +44,7 @@ This validates that all records in a child table have a corresponding record in
 people:
  constraints:
  relationships:
- - {from: account_id, to: accounts, field: id}
+ - {from: account_id, to: ref('accounts'), field: id}
 ```
 
 ### Accepted values