PostgreSQL schema dumper does not support capitalized table names

The postgresql adapter appears to have a bug that causes a PGError to be raised if there are any tables in the database that start with a capital letter.

This seems to be caused by the fact that in the SQL schema queries, the table name is cast to type regclass without using double quotes, so the case of the table name is not preserved. This causes the cast to fail if the table name starts with or contains capital letters.

For example, if there is a table "CamelCase" in the database, then the schema dumper will fail with the following error:

ActiveRecord::StatementInvalid: PGError: ERROR:  relation "camelcase" does not exist
:             SELECT a.attname, format_type(a.atttypid, a.atttypmod), d.adsrc, a.attnotnull
              FROM pg_attribute a LEFT JOIN pg_attrdef d
                ON a.attrelid = d.adrelid AND a.attnum = d.adnum
             WHERE a.attrelid = 'CamelCase'::regclass
               AND a.attnum > 0 AND NOT a.attisdropped
             ORDER BY a.attnum

The attached patch does the following:

• Introduces a capitalized table name into the test schema and reads the table name back to verify that the existing code works for MySQL and SQLite, but breaks for PostgreSQL.
• Adds quotes around the table name when casting to type regclass in the postgresql adapter.
• Improves postgresql table name quoting so that it quotes properly in the case of a prefixed schema as well (the schema should not be included in the quotes).
• Adds a test to the PostgreSQL schema test to verify that this works whether or not a schema is specified before the table name, e.g. test_schema.TableName

My environment:

• ActiveRecord 2.3.2
• PostgreSQL 8.2.11
• "pg" gem 0.8.0
• MacOS 10.5 Leopard