MySQL and Postgres schema_parse_table: retrieve comments

doc/reflection.rdoc

@@ -59,6 +59,7 @@ The hash may also contain entries for:
 Database#schema takes a table symbol and returns column information in an array with each element being an array with two elements.  The first elements of the subarray is a column symbol, and the second element is a hash of information about that column.  The hash should include the following keys:
 
 :allow_null :: Whether NULL/nil is an allowed value for this column. Used by the Sequel::Model typecasting code.
+:comment:: The comment of the column.
 :db_type :: The type of column the database provided, as a string.  Used by the schema_dumper plugin for a more specific type translation.
 :default :: The default value of the column, as either a string or nil.  Uses a database specific format. Used by the schema_dumper plugin for converting to a ruby value.
 :primary_key :: Whether this column is one of the primary key columns for the table.  Used by the Sequel::Model code to determine primary key columns.

lib/sequel/adapters/shared/mysql.rb

@@ -567,7 +567,7 @@ def schema_parse_table(table_name, opts)
         im = input_identifier_meth(opts[:dataset])
         table = SQL::Identifier.new(im.call(table_name))
         table = SQL::QualifiedIdentifier.new(im.call(opts[:schema]), table) if opts[:schema]
-        metadata_dataset.with_sql("DESCRIBE ?", table).map do |row|
+        metadata_dataset.with_sql("SHOW FULL COLUMNS FROM ?", table).map do |row|
           extra = row.delete(:Extra)
           if row[:primary_key] = row.delete(:Key) == 'PRI'
             row[:auto_increment] = !!(extra.to_s =~ /auto_increment/i)
@@ -577,8 +577,11 @@ def schema_parse_table(table_name, opts)
             row[:generated] = !!(extra.to_s =~ /VIRTUAL|STORED|PERSISTENT/i)
           end
           row[:allow_null] = row.delete(:Null) == 'YES'
+          row[:collation] = row.delete(:Collation)
+          row[:comment] = row.delete(:Comment)
           row[:default] = row.delete(:Default)
           row[:db_type] = row.delete(:Type)
+          row[:privileges] = row.delete(:Privileges)
           row[:type] = schema_column_type(row[:db_type])
           row[:extra] = extra
           [m.call(row.delete(:Field)), row]

lib/sequel/adapters/shared/postgres.rb

@@ -1075,6 +1075,7 @@ def _schema_ds
               pg_attribute[:attname].as(:name),
               SQL::Cast.new(pg_attribute[:atttypid], :integer).as(:oid),
               SQL::Cast.new(basetype[:oid], :integer).as(:base_oid),
+              pg_description[:description].as(:comment),
               SQL::Function.new(:format_type, basetype[:oid], pg_type[:typtypmod]).as(:db_base_type),
               SQL::Function.new(:format_type, pg_type[:oid], pg_attribute[:atttypmod]).as(:db_type),
               SQL::Function.new(:pg_get_expr, pg_attrdef[:adbin], pg_class[:oid]).as(:default),
@@ -1090,6 +1091,7 @@ def _schema_ds
             left_outer_join(Sequel[:pg_type].as(:elementtype), :typarray=>Sequel[:pg_type][:oid]).
             left_outer_join(:pg_attrdef, :adrelid=>Sequel[:pg_class][:oid], :adnum=>Sequel[:pg_attribute][:attnum]).
             left_outer_join(:pg_index, :indrelid=>Sequel[:pg_class][:oid], :indisprimary=>true).
+            left_outer_join(:pg_description, :objoid => Sequel[:pg_attribute][:attrelid]).
             where{{pg_attribute[:attisdropped]=>false}}.
             where{pg_attribute[:attnum] > 0}.
             order{pg_attribute[:attnum]}