Merge pull request #1113 from suketa/example_of_issue920

create sample script for ISSUE930

Author: suketa

sample/issue930.rb

@@ -0,0 +1,48 @@
+# frozen_string_literal: true
+
+require 'duckdb'
+require 'csv'
+
+require 'stringio'
+
+module DuckDB
+  class Connection
+    def register_as_table(name, io, csv_options: {}) # rubocop:disable Metrics/MethodLength, Metrics/AbcSize
+      csv = CSV.new(io, **csv_options)
+      headers = csv.first.headers
+      csv.rewind
+      columns = headers.each_with_object({}) { |header, hash| hash[header] = LogicalType::VARCHAR }
+      tf = DuckDB::TableFunction.create(
+        name:,
+        columns:
+      ) do |_func_info, output|
+        line = csv.readline
+        if line
+          line.each_with_index do |cell, index|
+            output.set_value(index, 0, cell[1])
+          end
+          1
+        else
+          csv.rewind
+          0
+        end
+      end
+      register_table_function(tf)
+    end
+  end
+end
+
+db = DuckDB::Database.open
+
+csv_data = "id,name,age\n1,Alice,30\n2,Bob,25\n3,Charlie,35"
+csv_data += 30_000.times.map { |i| "\n#{i + 4},Name#{i + 4},#{rand(0..100)}" }.join
+csv_io = StringIO.new(csv_data)
+
+con = db.connect
+con.query('SET threads=1')
+con.register_as_table('csv_io', csv_io, csv_options: { headers: true })
+result = con.query('SELECT * FROM csv_io()').to_a
+
+p result
+puts result.first.first == '1'
+puts result.first[1] == 'Alice'

sample/issue930_benchmark.rb

@@ -0,0 +1,68 @@
+# frozen_string_literal: true
+
+require 'duckdb'
+require 'csv'
+
+require 'stringio'
+
+module DuckDB
+  class Connection
+    def register_as_table_with_table_function(name, io, csv_options: {}) # rubocop:disable Metrics/AbcSize, Metrics/MethodLength
+      csv = CSV.new(io, **csv_options)
+      headers = csv.first.headers
+      csv.rewind
+      columns = headers.each_with_object({}) { |header, hash| hash[header] = LogicalType::VARCHAR }
+      tf = DuckDB::TableFunction.create(
+        name:,
+        columns:
+      ) do |_func_info, output|
+        line = csv.readline
+        if line
+          line.each_with_index do |cell, index|
+            output.set_value(index, 0, cell[1])
+          end
+          1
+        else
+          csv.rewind
+          0
+        end
+      end
+      register_table_function(tf)
+    end
+
+    def register_as_table_with_create_table(name, io, csv_options: {})
+      csv = CSV.new(io, **csv_options)
+      headers = csv.first.headers
+      csv.rewind
+      execute("CREATE OR REPLACE TABLE #{name} (#{headers.map { |h| "#{h} VARCHAR" }.join(', ')})")
+      csv.each do |row|
+        values = row.map { |cell| "'#{cell[1]}'" }.join(', ')
+        execute("INSERT INTO #{name} VALUES (#{values})")
+      end
+    end
+  end
+end
+
+csv_data = 'id,name,age'
+csv_data += 100_000.times.map { |i| "\n#{i + 1},Name#{i + 1},#{rand(0..100)}" }.join
+csv_io = StringIO.new(csv_data)
+
+db = DuckDB::Database.open
+con = db.connect
+con.query('SET threads=1')
+
+start_time = Process.clock_gettime(Process::CLOCK_MONOTONIC)
+con.register_as_table_with_table_function('csv_tf', csv_io, csv_options: { headers: true })
+con.query('SELECT * FROM csv_tf()').to_a
+end_time = Process.clock_gettime(Process::CLOCK_MONOTONIC)
+
+start_time2 = Process.clock_gettime(Process::CLOCK_MONOTONIC)
+con.register_as_table_with_create_table('csv_ct', csv_io, csv_options: { headers: true })
+con.query('SELECT * FROM csv_ct').to_a
+end_time2 = Process.clock_gettime(Process::CLOCK_MONOTONIC)
+
+con.close
+db.close
+
+puts "Time taken for table function approach: #{end_time - start_time} seconds"
+puts "Time taken for CREATE TABLE   approach: #{end_time2 - start_time2} seconds"