Quote databases properly (#1396)

[beckjake]

Fixes #1396

There are two bugs here: one is around lowercasing/uppercasing on quoting, and one is around not setting the database quote policy to true when listing relations. The latter is the issue reported in 1396, and I have a test for it that is... okay. I can't come up with a test for the former that doesn't involve creating a snowflake test database that is either lowercase or starts with a number.

Sadly, even though the bug is in the common base and sql adapters, all tests have to be against snowflake because only snowflake defaults to quoting = false.

While I was trying to get the tests running on postgres, I had to tweak PostgresAdapter.verify_database - we used to reject perfectly valid mixing of stuff like DBT and "dbt". I left that in, because the old way was wrong.

[drewbanin]

I don't think this solves the full problem here:

• In list_relations we create an information_schema Relation
• In the information_schema method, we use self.quote_policy to determine if we should quote the database
• self.quote_policy['database'] is False on Snowflake regardless of how quoting is configured in dbt_project.yml

I determined this in two ways:

1. I threw a debugger in here and checked out the value of self.quote_policy
2. I tried to run the following model against a Snowflake target with a database called 1234-test-abc:

select 1

{% do adapter.already_exists(this.schema, this.table) %}

Regardless of the quoting config specified in dbt_project.yml, dbt will not quote the database name when querying the information schema tables. I think we apply these quoting configs after parsing, as the code above fails, but the code below works in this branch:

select 1
{% if execute %}
    {% do adapter.already_exists(this.schema, this.table) %}
{% endif %}

[drewbanin]

LGTM!

@tayloramurphy are you able to try installing from this branch and testing out your use case? The code here looks good, and I gave it a spin locally too. If you're able to test it out, I'd feel really good about merging this in

[drewbanin]

This isn't the most pleasant thing in the world, but I think it's a good and appropriate fix for this problem. Nice

[drewbanin]

-.- is exactly how i feel about Snowflake quoting

[drewbanin]

Can you update https://github.com/fishtown-analytics/dbt/blob/dev/wilt-chamberlain/test.env.sample accordingly?