From 84974cf09220105bc7a92e5bcde31f52827c1de7 Mon Sep 17 00:00:00 2001
From: Frazer McLean <frazer@frazermclean.co.uk>
Date: Mon, 13 Jun 2016 10:31:18 -0400
Subject: Comment support

Implementation of [#1546 (BitBucket)](https://bitbucket.org/zzzeek/sqlalchemy/issues/1546).

Very unfinished but I have reflection and setting after table creation working for PostgreSQL.

If you're not opposed, perhaps best to continue discussion on Gerrit?

Change-Id: Ib90683850805a2b4ee198e420dc294f32f15d35d
Pull-request: https://github.com/zzzeek/sqlalchemy/pull/284
---
 lib/sqlalchemy/dialects/postgresql/base.py | 34 +++++++++++++++++++++++++-----
 1 file changed, 29 insertions(+), 5 deletions(-)

(limited to 'lib/sqlalchemy/dialects/postgresql')

diff --git a/lib/sqlalchemy/dialects/postgresql/base.py b/lib/sqlalchemy/dialects/postgresql/base.py
index 16b22129a..3c111e3cc 100644
--- a/lib/sqlalchemy/dialects/postgresql/base.py
+++ b/lib/sqlalchemy/dialects/postgresql/base.py
@@ -2057,8 +2057,11 @@ class PGDialect(default.DefaultDialect):
                WHERE d.adrelid = a.attrelid AND d.adnum = a.attnum
                AND a.atthasdef)
               AS DEFAULT,
-              a.attnotnull, a.attnum, a.attrelid as table_oid
+              a.attnotnull, a.attnum, a.attrelid as table_oid,
+              pgd.description as comment
             FROM pg_catalog.pg_attribute a
+            LEFT JOIN pg_catalog.pg_description pgd ON (
+                pgd.objoid = a.attrelid AND pgd.objsubid = a.attnum)
             WHERE a.attrelid = :table_oid
             AND a.attnum > 0 AND NOT a.attisdropped
             ORDER BY a.attnum
@@ -2082,14 +2085,16 @@ class PGDialect(default.DefaultDialect):
 
         # format columns
         columns = []
-        for name, format_type, default, notnull, attnum, table_oid in rows:
+        for name, format_type, default, notnull, attnum, table_oid, \
+                comment in rows:
             column_info = self._get_column_info(
-                name, format_type, default, notnull, domains, enums, schema)
+                name, format_type, default, notnull, domains, enums,
+                schema, comment)
             columns.append(column_info)
         return columns
 
     def _get_column_info(self, name, format_type, default,
-                         notnull, domains, enums, schema):
+                         notnull, domains, enums, schema, comment):
         # strip (*) from character varying(5), timestamp(5)
         # with time zone, geometry(POLYGON), etc.
         attype = re.sub(r'\(.*\)', '', format_type)
@@ -2196,7 +2201,8 @@ class PGDialect(default.DefaultDialect):
                         match.group(2) + match.group(3)
 
         column_info = dict(name=name, type=coltype, nullable=nullable,
-                           default=default, autoincrement=autoincrement)
+                           default=default, autoincrement=autoincrement,
+                           comment=comment)
         return column_info
 
     @reflection.cache
@@ -2527,6 +2533,24 @@ class PGDialect(default.DefaultDialect):
             for name, uc in uniques.items()
         ]
 
+    @reflection.cache
+    def get_table_comment(self, connection, table_name, schema=None, **kw):
+        table_oid = self.get_table_oid(connection, table_name, schema,
+                                       info_cache=kw.get('info_cache'))
+
+        COMMENT_SQL = """
+            SELECT
+                pgd.description as table_comment
+            FROM
+                pg_catalog.pg_description pgd
+            WHERE
+                pgd.objsubid = 0 AND
+                pgd.objoid = :table_oid
+        """
+
+        c = connection.execute(sql.text(COMMENT_SQL), table_oid=table_oid)
+        return c.scalar()
+
     @reflection.cache
     def get_check_constraints(
             self, connection, table_name, schema=None, **kw):
-- 
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