drop_index not work on postgresql

[OnePieceLv]

Describe the bug
add an index to column success, but failed to drop the index when migrating rollback

To Reproduce
Steps to reproduce the behavior:

1. create a migration file.
2. add an index to the column in the up method
3. execute migrate
4. drop the same index in the down method
5. execute migrate rollback. and failed

Expected behavior
drop_index generate sql ALTER TABLE table_name DROP CONSTRAINT table_name_column_index.
but in postgresql should be DROP INDEX table_name_column_index

Screenshots or code snippets
Failure
.

Success

Desktop (please complete the following information):

• OS: macOS
• Version Big Sur

What database are you using?

• Type: Postgres
• Version 12.2
• Masonite ORM v1.0.47
• Docker Environment: Postgres Office Image (postgres:12.2)

Additional context
In the end, I execute the SQL statement DROP INDEX .... complete requirements

[OnePieceLv]

I execute command \d+ table_name. I can see the index

but I execute the SQL
SELECT * FROM information_schema.constraint_table_usage WHERE table_name = 'table_name'.
I don't see any related constraints

[josephmancuso]

Looked into this issue. The problem is that currently the drop indexes and drop constraints are tied together in the Table class.

We are tying indexes in with unique constraints. Postgres treats these differently so we either need to somehow identify them or separate them out in the Table class and iterate through them differently in the platform classes.

[holic-cl]

I have same issue:

My Migration:

class AddIndexesToRelationships(Migration):
    def up(self):
        """
        Run the migrations.
        """
        with self.schema.table('branches') as table:
            table.index('code')

    def down(self):
        """
        Revert the migrations.
        """
        with self.schema.table('branches') as table:
            table.drop_index(['code'])

My database after run the migration:

opticks=# \d branches
                                        Table "public.branches"
   Column   |            Type             | Collation | Nullable |               Default                
------------+-----------------------------+-----------+----------+--------------------------------------
 id         | integer                     |           | not null | nextval('branches_id_seq'::regclass)
 code       | character varying(255)      |           | not null | 
 name       | character varying(255)      |           | not null | 
 created_at | timestamp without time zone |           |          | CURRENT_TIMESTAMP
 updated_at | timestamp without time zone |           |          | CURRENT_TIMESTAMP
Indexes:
    "branches_id_primary" PRIMARY KEY, btree (id)
    "branches_code_unique" UNIQUE CONSTRAINT, btree (code)
    "branches_code_index" btree (code)
Referenced by:
    TABLE "warehouses" CONSTRAINT "warehouses_branch_id_foreign" FOREIGN KEY (branch_id) REFERENCES branches(id)

The error i got:

  QueryException

  constraint "branches_code_index" of relation "branches" does not exist