5 files changed, 104 insertions, 0 deletions
diff --git a/lib/sqlalchemy/dialects/mysql/base.py b/lib/sqlalchemy/dialects/mysql/base.py
index 9d856e271..2642b5fdc 100644
--- a/lib/sqlalchemy/dialects/mysql/base.py
+++ b/lib/sqlalchemy/dialects/mysql/base.py
@@ -2212,6 +2212,21 @@ class MySQLDialect(default.DefaultDialect):
         return indexes
 
     @reflection.cache
+    def get_unique_constraints(self, connection, table_name,
+                               schema=None, **kw):
+        parsed_state = self._parsed_state_or_create(
+            connection, table_name, schema, **kw)
+
+        return [
+            {
+                'name': key['name'],
+                'column_names': [col[0] for col in key['columns']]
+            }
+            for key in parsed_state.keys
+            if key['type'] == 'UNIQUE'
+        ]
+
+    @reflection.cache
     def get_view_definition(self, connection, view_name, schema=None, **kw):
 
         charset = self._connection_charset
diff --git a/lib/sqlalchemy/dialects/postgresql/base.py b/lib/sqlalchemy/dialects/postgresql/base.py
index 00d0acc2c..0810e0384 100644
--- a/lib/sqlalchemy/dialects/postgresql/base.py
+++ b/lib/sqlalchemy/dialects/postgresql/base.py
@@ -1950,6 +1950,36 @@ class PGDialect(default.DefaultDialect):
             index_d['unique'] = unique
         return indexes
 
+    @reflection.cache
+    def get_unique_constraints(self, connection, table_name,
+                               schema=None, **kw):
+        table_oid = self.get_table_oid(connection, table_name, schema,
+                                       info_cache=kw.get('info_cache'))
+
+        UNIQUE_SQL = """
+            SELECT
+                cons.conname as name,
+                ARRAY_AGG(a.attname) as column_names
+            FROM
+                pg_catalog.pg_constraint cons
+                left outer join pg_attribute a
+                    on cons.conrelid = a.attrelid and a.attnum = ANY(cons.conkey)
+            WHERE
+                cons.conrelid = :table_oid AND
+                cons.contype = 'u'
+            GROUP BY
+                cons.conname
+        """
+
+        t = sql.text(UNIQUE_SQL,
+                     typemap={'column_names': ARRAY(sqltypes.Unicode)})
+        c = connection.execute(t, table_oid=table_oid)
+
+        return [
+            {'name': row.name, 'column_names': row.column_names}
+            for row in c.fetchall()
+        ]
+
     def _load_enums(self, connection):
         if not self.supports_native_enum:
             return {}
diff --git a/lib/sqlalchemy/dialects/sqlite/base.py b/lib/sqlalchemy/dialects/sqlite/base.py
index c7e09b164..3e2a158a0 100644
--- a/lib/sqlalchemy/dialects/sqlite/base.py
+++ b/lib/sqlalchemy/dialects/sqlite/base.py
@@ -917,6 +917,26 @@ class SQLiteDialect(default.DefaultDialect):
                 cols.append(row[2])
         return indexes
 
+    @reflection.cache
+    def get_unique_constraints(self, connection, table_name,
+                               schema=None, **kw):
+        UNIQUE_SQL = """
+            SELECT sql
+            FROM
+                sqlite_master
+            WHERE
+                type='table' AND
+                name=:table_name
+        """
+        c = connection.execute(UNIQUE_SQL, table_name=table_name)
+        table_data = c.fetchone()[0]
+
+        UNIQUE_PATTERN = 'CONSTRAINT (\w+) UNIQUE \(([^\)]+)\)'
+        return [
+            {'name': name, 'column_names': [c.strip() for c in cols.split(',')]}
+            for name, cols in re.findall(UNIQUE_PATTERN, table_data)
+        ]
+
 
 def _pragma_cursor(cursor):
     """work around SQLite issue whereby cursor.description
diff --git a/lib/sqlalchemy/engine/interfaces.py b/lib/sqlalchemy/engine/interfaces.py
index f623a2a61..d5fe5c5e2 100644
--- a/lib/sqlalchemy/engine/interfaces.py
+++ b/lib/sqlalchemy/engine/interfaces.py
@@ -338,6 +338,25 @@ class Dialect(object):
 
         raise NotImplementedError()
 
+    def get_unique_constraints(self, table_name, schema=None, **kw):
+        """Return information about unique constraints in `table_name`.
+
+        Given a string `table_name` and an optional string `schema`, return
+        unique constraint information as a list of dicts with these keys:
+
+        name
+          the unique constraint's name
+
+        column_names
+          list of column names in order
+
+        \**kw
+          other options passed to the dialect's get_unique_constraints() method.
+
+        """
+
+        raise NotImplementedError()
+
     def normalize_name(self, name):
         """convert the given name to lowercase if it is detected as
         case insensitive.
diff --git a/lib/sqlalchemy/engine/reflection.py b/lib/sqlalchemy/engine/reflection.py
index cf2caf679..1926e693a 100644
--- a/lib/sqlalchemy/engine/reflection.py
+++ b/lib/sqlalchemy/engine/reflection.py
@@ -347,6 +347,26 @@ class Inspector(object):
                                                   schema,
                                             info_cache=self.info_cache, **kw)
 
+    def get_unique_constraints(self, table_name, schema=None, **kw):
+        """Return information about unique constraints in `table_name`.
+
+        Given a string `table_name` and an optional string `schema`, return
+        unique constraint information as a list of dicts with these keys:
+
+        name
+          the unique constraint's name
+
+        column_names
+          list of column names in order
+
+        \**kw
+          other options passed to the dialect's get_unique_constraints() method.
+
+        """
+
+        return self.dialect.get_unique_constraints(
+            self.bind, table_name, schema, info_cache=self.info_cache, **kw)
+
     def reflecttable(self, table, include_columns, exclude_columns=()):
         """Given a Table object, load its internal constructs based on
         introspection.