Changed change_column in PG schema_statements.rb to make sure that the uuid_generate function was not being quoted.

[Yves Senn & Matthew Draper]

Expand the query used in #table_exists? to include materialized views in the
kinds of relations it searches.

The pk_an_sequence_for query previously joined against pg_class's oid
for rows in pg_depend, but pg_depend's objid may point to other system
tables, such as pg_attrdef.  If a row in one of those other tables
coincidentally has the same oid as an (unrelated) sequence, that
sequence name may be returned instead of the real one.

This ensures that only the pg_depend entries pointing to pg_class are
considered.

Reject blank order_values within #columns_for_distinct, as the orders aren't used at all on non-postgres adapters.

The combination of a :uniq => true association and the #distinct call
in #construct_limited_ids_condition combine to create invalid SQL, because
we're explicitly selecting DISTINCT, and also sending #distinct on to AREL,
via the relation#distinct_value.

Rather than build a select distinct clause in #construct_limited_ids_condition,
I set #distinct! and pass just the columns into the select statement.
This requires introducing a #columns_for_distinct method to return the
select columns but not the statement itself.

When building the indexes list in PostgreSQL, IndexDefinition objects
are only created if the query for the related attributes really returns
something matching the attributes.

In case it does not, the variables for building the definition objects were
being created but not used.

Adds support for algorithm option in MySQL indexes
Moves USING and algorithm options upstream

The syntax is still specific to the Adapter, so the actual executed string happens
in the corresponding adapter

When a table or a column is renamed related indexes kept their name. This will lead to confusing names. This patch renames related indexes when a column or a table is renamed. Only indexes with names generated by rails will be renamed. Indexes with custom names will not be renamed.

If we set encoding latin1 for a PostgreSQL database, it calls
PostgreSQLAdapter::create_database with options that have,
among other things:

  { 'encoding' => 'latin1' }

Then, we use reverse_merge(:encoding => "utf8") to setup the default
encoding. In the end, the hash looks like:

  { :encoding => 'utf8', 'encoding' => 'latin1' }

The call to options.symbolize_keys calls to_sym on each_key of this
Hash. It usually means that the encoding passed overwrites the default
utf8, but it's not guaranteed. So, we shouldn't rely on it.

The same was happening in ActiveRecord::ConnectionHandling.

Remove parsing of character type default values for 8.1 formatting since
Rails doesn't support postgreSQL 8.1 anymore.

Remove misleading comment unrelated to code.

According to postgreSQL documentation:
(http://www.postgresql.org/docs/8.2/static/catalog-pg-attrdef.html)
we should not be using 'adsrc' field because this field is unaware of
outside changes that could affect the way that default values are
represented. Thus, I changed the queries to use
"pg_get_expr(adbin, adrelid)" instead of the historical "adsrc" field.