Class: DBConnection

Inherits:
Object
  • Object
show all
Defined in:
lib/db_connection.rb

Class Method Summary collapse

Class Method Details

.add_to_version(file) ⇒ Object 



48
49
50
51
52
53
54
55
56
 
# File 'lib/db_connection.rb', line 48

def self.add_to_version(file)
  name = parse_migration_file(file)
  execute(<<-SQL, [name])
    INSERT INTO
      version (name)
    VALUES
      ($1);
  SQL
end

.columns(table_name) ⇒ Object 



83
84
85
86
87
88
89
90
91
92
93
94
95
96
 
# File 'lib/db_connection.rb', line 83

def self.columns(table_name)
  columns = instance.exec(<<-SQL)
    SELECT
      attname
    FROM
      pg_attribute
    WHERE
      attrelid = '#{table_name}'::regclass AND
      attnum > 0 AND
      NOT attisdropped
  SQL

  columns.map { |col| col['attname'].to_sym }
end

.ensure_version_table ⇒ Object 



69
70
71
72
73
74
75
76
77
78
79
80
81
 
# File 'lib/db_connection.rb', line 69

def self.ensure_version_table
  #find a reliable way to query db to see if version table exists.
  table = nil

  if table.nil?
    self.execute(<<-SQL)
      CREATE TABLE IF NOT EXISTS version (
        id SERIAL PRIMARY KEY,
        name VARCHAR(255) NOT NULL
      );
    SQL
  end
end

.execute(*args) ⇒ Object 



64
65
66
67
 
# File 'lib/db_connection.rb', line 64

def self.execute(*args)
  print_query(*args)
  instance.exec(*args)
end

.has_migrated?(file) ⇒ Boolean

Returns:

  • (Boolean) 


35
36
37
38
39
40
41
42
43
44
45
46
 
# File 'lib/db_connection.rb', line 35

def self.has_migrated?(file)
  name = parse_migration_file(file)
  result = execute(<<-SQL, [name])
    SELECT
      *
    FROM
      version
    WHERE
      name = $1;
  SQL
  !!result.first
end

.instance ⇒ Object 



58
59
60
61
62
 
# File 'lib/db_connection.rb', line 58

def self.instance
  self.open if @db.nil?

  @db
end

.migrate ⇒ Object 



21
22
23
24
25
26
27
 
# File 'lib/db_connection.rb', line 21

def self.migrate
  ensure_version_table
  to_migrate = MIGRATIONS.reject { |file| has_migrated?(file) }
  to_migrate.each { |file| add_to_version(file) }
  to_migrate.map {|file| "psql -d #{APP_NAME} -a -f #{file}"}
            .each {|command| `#{command}`}
end

.open ⇒ Object 



8
9
10
 
# File 'lib/db_connection.rb', line 8

def self.open
  @db = PG::Connection.new( :dbname => APP_NAME, :port => 5432 )
end

.parse_migration_file(file) ⇒ Object 



29
30
31
32
33
 
# File 'lib/db_connection.rb', line 29

def self.parse_migration_file(file)
  filename = File.basename(file).split(".").first
  u_idx = filename.index("_")
  filename[0..u_idx - 1]
end

.reset ⇒ Object 



12
13
14
15
16
17
18
19
 
# File 'lib/db_connection.rb', line 12

def self.reset
  commands = [
    "dropdb #{APP_NAME}",
    "createdb #{APP_NAME}",
  ]

  commands.each { |command| `#{command}` }
end