Class: AddNumberColumnToRecorderRevisions

Inherits:
ActiveRecord::Migration
  • Object
show all
Defined in:
lib/generators/recorder/templates/add_number_column_to_recorder_revisions.rb

Overview

This migration adds number column to the ‘revisions` table.

Instance Method Summary collapse

Instance Method Details

#down ⇒ Object 



33
34
35
36
37
38
39
40
41
42
43
 
# File 'lib/generators/recorder/templates/add_number_column_to_recorder_revisions.rb', line 33

def down
  execute <<-SQL
    DROP TRIGGER update_recorder_revisions_number;
  SQL

  execute <<-SQL
    DROP FUNCTION IF EXISTS get_recorder_revisions_number;
  SQL

  remove_column :recorder_revisions, :number
end

#up ⇒ Object 



5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
 
# File 'lib/generators/recorder/templates/add_number_column_to_recorder_revisions.rb', line 5

def up
  add_column :recorder_revisions, :number, :integer, null: false, default: 0

  execute <<~SQL
          CREATE OR REPLACE FUNCTION get_recorder_revisions_number()
            RETURNS trigger AS
          $BODY$
          BEGIN
              SELECT COALESCE(MAX(recorder_revisions.number), 0) + 1
              INTO NEW.number
              FROM
                recorder_revisions
              WHERE
                recorder_revisions.item_type = NEW.item_type
                AND recorder_revisions.item_id = NEW.item_id;
    #{"      "}
              RETURN NEW;
          END;
          $BODY$ LANGUAGE plpgsql;
  SQL

  execute <<~SQL
    CREATE TRIGGER update_recorder_revisions_number
      BEFORE INSERT ON recorder_revisions FOR EACH ROW
      EXECUTE PROCEDURE get_recorder_revisions_number();
  SQL
end