Method: ActiveRecord::ConnectionAdapters::SQLite3::SchemaStatements#indexes

Defined in:
activerecord/lib/active_record/connection_adapters/sqlite3/schema_statements.rb

#indexes(table_name) ⇒ Object

Returns an array of indexes for the given table.



8
9
10
11
12
13
14
15
16
17
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
53
 
# File 'activerecord/lib/active_record/connection_adapters/sqlite3/schema_statements.rb', line 8

def indexes(table_name)
  internal_exec_query("PRAGMA index_list(#{quote_table_name(table_name)})", "SCHEMA").filter_map do |row|
    # Indexes SQLite creates implicitly for internal use start with "sqlite_".
    # See https://www.sqlite.org/fileformat2.html#intschema
    next if row["name"].start_with?("sqlite_")

    index_sql = query_value(<<~SQL, "SCHEMA")
      SELECT sql
      FROM sqlite_master
      WHERE name = #{quote(row['name'])} AND type = 'index'
      UNION ALL
      SELECT sql
      FROM sqlite_temp_master
      WHERE name = #{quote(row['name'])} AND type = 'index'
    SQL

    /\bON\b\s*"?(\w+?)"?\s*\((?<expressions>.+?)\)(?:\s*WHERE\b\s*(?<where>.+))?(?:\s*\/\*.*\*\/)?\z/i =~ index_sql

    columns = internal_exec_query("PRAGMA index_info(#{quote(row['name'])})", "SCHEMA").map do |col|
      col["name"]
    end

    orders = {}

    if columns.any?(&:nil?) # index created with an expression
      columns = expressions
    else
      # Add info on sort order for columns (only desc order is explicitly specified,
      # asc is the default)
      if index_sql # index_sql can be null in case of primary key indexes
        index_sql.scan(/"(\w+)" DESC/).flatten.each { |order_column|
          orders[order_column] = :desc
        }
      end
    end

    IndexDefinition.new(
      table_name,
      row["name"],
      row["unique"] != 0,
      columns,
      where: where,
      orders: orders
    )
  end
end