Module: EnhancedSQLite3::SupportsDeferrableConstraints::Adapter

Defined in:
lib/enhanced_sqlite3/supports_deferrable_constraints.rb

Constant Summary collapse

FK_REGEX = 
/.*FOREIGN KEY\s+\("(\w+)"\)\s+REFERENCES\s+"(\w+)"\s+\("(\w+)"\)/
DEFERRABLE_REGEX = 
/DEFERRABLE INITIALLY (\w+)/

Instance Method Summary collapse

Instance Method Details

#add_foreign_key(from_table, to_table, **options) ⇒ Object 



54
55
56
57
58
59
60
61
62
63
64
65
66
 
# File 'lib/enhanced_sqlite3/supports_deferrable_constraints.rb', line 54

def add_foreign_key(from_table, to_table, **options)
  if options[:deferrable] == true
    ActiveRecord.deprecator.warn(<<~MSG)
      `deferrable: true` is deprecated in favor of `deferrable: :immediate`, and will be removed in Rails 7.2.
    MSG

    options[:deferrable] = :immediate
  end

  assert_valid_deferrable(options[:deferrable])

  super
end

#assert_valid_deferrable(deferrable) ⇒ Object

Raises:

  • (ArgumentError) 


90
91
92
93
94
 
# File 'lib/enhanced_sqlite3/supports_deferrable_constraints.rb', line 90

def assert_valid_deferrable(deferrable)
  return if !deferrable || %i[immediate deferred].include?(deferrable)

  raise ArgumentError, "deferrable must be `:immediate` or `:deferred`, got: `#{deferrable.inspect}`"
end

#foreign_keys(table_name) ⇒ Object 



18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
 
# File 'lib/enhanced_sqlite3/supports_deferrable_constraints.rb', line 18

def foreign_keys(table_name)
  # SQLite returns 1 row for each column of composite foreign keys.
  fk_info = internal_exec_query("PRAGMA foreign_key_list(#{quote(table_name)})", "SCHEMA")
  # Deferred or immediate foreign keys can only be seen in the CREATE TABLE sql
  fk_defs = table_structure_sql(table_name)
    .select do |column_string|
              column_string.start_with?("CONSTRAINT") &&
                column_string.include?("FOREIGN KEY")
            end
    .to_h do |fk_string|
    _, from, table, to = fk_string.match(FK_REGEX).to_a
    _, mode = fk_string.match(DEFERRABLE_REGEX).to_a
    deferred = mode&.downcase&.to_sym || false
    [[table, from, to], deferred]
  end

  grouped_fk = fk_info.group_by { |row| row["id"] }.values.each { |group| group.sort_by! { |row| row["seq"] } }
  grouped_fk.map do |group|
    row = group.first
    options = {
      on_delete: extract_foreign_key_action(row["on_delete"]),
      on_update: extract_foreign_key_action(row["on_update"]),
      deferrable: fk_defs[[row["table"], row["from"], row["to"]]]
    }

    if group.one?
      options[:column] = row["from"]
      options[:primary_key] = row["to"]
    else
      options[:column] = group.map { |row| row["from"] }
      options[:primary_key] = group.map { |row| row["to"] }
    end
    ActiveRecord::ConnectionAdapters::ForeignKeyDefinition.new(table_name, row["table"], options)
  end
end

#supports_deferrable_constraints? ⇒ Boolean

Returns:

  • (Boolean) 


12
13
14
 
# File 'lib/enhanced_sqlite3/supports_deferrable_constraints.rb', line 12

def supports_deferrable_constraints?
  true
end

#table_structure_sql(table_name) ⇒ Object 



68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
 
# File 'lib/enhanced_sqlite3/supports_deferrable_constraints.rb', line 68

def table_structure_sql(table_name)
  sql = <<~SQL
    SELECT sql FROM
      (SELECT * FROM sqlite_master UNION ALL
       SELECT * FROM sqlite_temp_master)
    WHERE type = 'table' AND name = #{quote(table_name)}
  SQL

  # Result will have following sample string
  # CREATE TABLE "users" ("id" INTEGER PRIMARY KEY AUTOINCREMENT NOT NULL,
  #                       "password_digest" varchar COLLATE "NOCASE");
  result = query_value(sql, "SCHEMA")

  return [] unless result

  # Splitting with left parentheses and discarding the first part will return all
  # columns separated with comma(,).
  columns_string = result.split("(", 2).last

  columns_string.split(",").map(&:strip)
end