table_structure_with_collation

# File activerecord/lib/active_record/connection_adapters/sqlite3_adapter.rb, line 487
        def table_structure_with_collation(table_name, basic_structure)
          collation_hash = {}
          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")

          if 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(",").each do |column_string|
              # This regex will match the column name and collation type and will save
              # the value in $1 and $2 respectively.
              collation_hash[$1] = $2 if COLLATE_REGEX =~ column_string
            end

            basic_structure.map do |column|
              column_name = column["name"]

              if collation_hash.has_key? column_name
                column["collation"] = collation_hash[column_name]
              end

              column
            end
          else
            basic_structure.to_a
          end
        end