Class: Exwiw::Adapter::Mysql2Adapter

Inherits:
Base
  • Object
show all
Defined in:
lib/exwiw/adapter/mysql2_adapter.rb

Instance Attribute Summary

Attributes inherited from Base

#connection_config

Instance Method Summary collapse

Methods inherited from Base

#dumpable?, #initialize, #output_extension, #post_insert_sql, #schema_output_extension, #supports_bulk_delete?, table_config_class, #to_copy_from_stdin, #validate_as_dump_target!

Constructor Details

This class inherits a constructor from Exwiw::Adapter::Base

Instance Method Details

#build_query(table, dump_target, table_by_name) ⇒ Object 



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# File 'lib/exwiw/adapter/mysql2_adapter.rb', line 6

def build_query(table, dump_target, table_by_name)
  Exwiw::QueryAstBuilder.run(table.name, table_by_name, dump_target, @logger)
end

#compile_ast(query_ast) ⇒ Object

Raises:

  • (NotImplementedError) 


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# File 'lib/exwiw/adapter/mysql2_adapter.rb', line 140

def compile_ast(query_ast)
  raise NotImplementedError unless query_ast.is_a?(Exwiw::QueryAst::Select)

  sql = "SELECT "
  sql += query_ast.columns.map { |col| compile_column_name(query_ast, col) }.join(', ')
  sql += " FROM #{query_ast.from_table_name}"

  query_ast.join_clauses.each do |join|
    sql += " JOIN #{join.join_table_name} ON #{join.base_table_name}.#{join.foreign_key} = #{join.join_table_name}.#{join.primary_key}"

    join.where_clauses.each do |where|
      compiled_where_condition = compile_where_condition(where, join.join_table_name)
      sql += " AND #{compiled_where_condition}"
    end
  end

  if query_ast.where_clauses.any?
    sql += " WHERE "
    sql += query_ast.where_clauses.map { |where| compile_where_condition(where, query_ast.from_table_name) }.join(' AND ')
  end

  sql
end

#dump_schema(ordered_tables, output_path) ⇒ Object 



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# File 'lib/exwiw/adapter/mysql2_adapter.rb', line 28

def dump_schema(ordered_tables, output_path)
  require 'open3'

  table_names = ordered_tables.map(&:name)
  if table_names.empty?
    File.write(output_path, "-- Auto-generated by exwiw. No tables in scope.\n")
    return
  end

  cmd = [
    'mysqldump',
    "--host=#{@connection_config.host}",
    "--port=#{@connection_config.port}",
    "--user=#{@connection_config.user}",
    '--no-data',
    '--skip-add-drop-table',
    # `--skip-comments` only suppresses the dump's header lines
    # (e.g. `-- MySQL dump ...`, server version banner). Column and
    # table `COMMENT '...'` clauses are emitted inline inside
    # CREATE TABLE statements and are NOT affected, so this flag is
    # purely about reducing noise in the generated file.
    '--skip-comments',
    '--skip-set-charset',
    # Suppress `SET @@GLOBAL.GTID_PURGED=...` from the dump. It is intended
    # for replication setup and breaks when the target already has GTIDs
    # (ERROR 3546: added gtid set must not overlap with @@GLOBAL.GTID_EXECUTED).
    '--set-gtid-purged=OFF',
    '--compact',
    @connection_config.database_name,
    *table_names,
  ]
  env = { 'MYSQL_PWD' => @connection_config.password.to_s }

  @logger.debug("  Running mysqldump for #{table_names.size} table(s)...")
  stdout, stderr, status = Open3.capture3(env, *cmd)
  unless status.success?
    if stderr.include?('command not found') || stderr.empty?
      raise "Failed to run `mysqldump`. Ensure the mysql client is installed and on PATH. stderr: #{stderr}"
    end
    raise "mysqldump failed (exit #{status.exitstatus}): #{stderr}"
  end

  idempotent = DdlPostprocessor.add_if_not_exists_to_create_table(stdout)

  File.open(output_path, 'w') do |file|
    file.puts("-- Auto-generated by exwiw via mysqldump. Idempotent CREATE TABLE statements for mysql.")
    file.write(idempotent)
  end
  @logger.info("  Wrote schema for #{table_names.size} table(s) to #{output_path}.")
end

#execute(query_ast) ⇒ Object 



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# File 'lib/exwiw/adapter/mysql2_adapter.rb', line 10

def execute(query_ast)
  sql = compile_ast(query_ast)

  @logger.debug("  Executing SQL: \n#{sql}")
  connection.query(sql, cast: false, as: :array).to_a
end

#explain(query_ast) ⇒ Object 



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# File 'lib/exwiw/adapter/mysql2_adapter.rb', line 17

def explain(query_ast)
  sql = compile_ast(query_ast)

  @logger.debug("  Executing EXPLAIN: \n#{sql}")
  rows = connection.query("EXPLAIN #{sql}", cast: false).to_a
  rows.each_with_index.flat_map do |row, i|
    ["*************************** #{i + 1}. row ***************************"] +
      row.map { |k, v| "#{k}: #{v}" }
  end.join("\n")
end

#to_bulk_delete(select_query_ast, table) ⇒ Object

Raises:

  • (NotImplementedError) 


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# File 'lib/exwiw/adapter/mysql2_adapter.rb', line 94

def to_bulk_delete(select_query_ast, table)
  raise NotImplementedError unless select_query_ast.is_a?(Exwiw::QueryAst::Select)

  sql = "DELETE FROM #{select_query_ast.from_table_name}"

  if select_query_ast.join_clauses.empty?
    # Ignore filter option, because bulk delete is for cleaning before import,
    # so it should delete all records to avoid foreign key violation & data consistancy.
    compiled_where_conditions = select_query_ast.
      where_clauses.
      select { |where| where.is_a?(Exwiw::QueryAst::WhereClause) }.
      map do |where|
      compile_where_condition(where, select_query_ast.from_table_name)
    end

    if compiled_where_conditions.size > 0
      sql += "\nWHERE "
      sql += compiled_where_conditions.join(' AND ')
    end
    sql += ";"

    return sql
  end

  subquery_ast = Exwiw::QueryAst::Select.new
  first_join = select_query_ast.join_clauses.first.clone

  subquery_ast.from(first_join.join_table_name)
  primay_key_col = table.columns.find { |col| col.name == table.primary_key }
  subquery_ast.select([primay_key_col])
  select_query_ast.join_clauses[1..].each do |join|
    subquery_ast.join(join)
  end
  first_join.where_clauses.each do |where|
    # Ignore filter option, because bulk delete is for cleaning before import,
    # so it should delete all records to avoid foreign key violation & data consistancy.
    subquery_ast.where(where) if where.is_a?(Exwiw::QueryAst::WhereClause)
  end

  foreign_key = first_join.foreign_key
  subquery_sql = compile_ast(subquery_ast)
  sql += "\nWHERE #{select_query_ast.from_table_name}.#{foreign_key} IN (#{subquery_sql});"

  sql
end

#to_bulk_insert(results, table) ⇒ Object 



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# File 'lib/exwiw/adapter/mysql2_adapter.rb', line 79

def to_bulk_insert(results, table)
  table_name = table.name

  value_list = results.map do |row|
    quoted_values = row.map do |value|
      escape_value(value)
    end
    "(" + quoted_values.join(', ') + ")"
  end
  values = value_list.join(",\n")

  column_names = table.columns.map(&:name).join(', ')
  "INSERT INTO #{table_name} (#{column_names}) VALUES\n#{values};"
end