class ActiveRecord::ConnectionAdapters::AbstractMysqlAdapter

# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 560
def add_column_position!(sql, options)
  if options[:first]
    sql << " FIRST"
  elsif options[:after]
    sql << " AFTER #{quote_column_name(options[:after])}"
  end
end

# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 318
def begin_db_transaction
  execute "BEGIN"
end

# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 322
def begin_isolated_db_transaction(isolation)
  execute "SET TRANSACTION ISOLATION LEVEL #{transaction_isolation_levels.fetch(isolation)}"
  begin_db_transaction
end

# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 597
def case_insensitive_comparison(table, attribute, column, value)
  if column.case_sensitive?
    super
  else
    table[attribute].eq(value)
  end
end

# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 593
def case_sensitive_modifier(node)
  Arel::Nodes::Bin.new(node)
end

# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 499
def change_column_default(table_name, column_name, default)
  column = column_for(table_name, column_name)
  change_column table_name, column_name, column.sql_type, :default => default
end

# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 504
def change_column_null(table_name, column_name, null, default = nil)
  column = column_for(table_name, column_name)

  unless null || default.nil?
    execute("UPDATE #{quote_table_name(table_name)} SET #{quote_column_name(column_name)}=#{quote(default)} WHERE #{quote_column_name(column_name)} IS NULL")
  end

  change_column table_name, column_name, column.sql_type, :null => null
end

# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 390
def charset
  show_variable 'character_set_database'
end

# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 395
def collation
  show_variable 'collation_database'
end

# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 369
def create_database(name, options = {})
  if options[:collation]
    execute "CREATE DATABASE `#{name}` DEFAULT CHARACTER SET `#{options[:charset] || 'utf8'}` COLLATE `#{options[:collation]}`"
  else
    execute "CREATE DATABASE `#{name}` DEFAULT CHARACTER SET `#{options[:charset] || 'utf8'}`"
  end
end

# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 385
def current_database
  select_value 'SELECT DATABASE() as db'
end

# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 487
def drop_table(table_name, options = {})
  execute "DROP#{' TEMPORARY' if options[:temporary]} TABLE #{quote_table_name(table_name)}"
end

# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 347
def empty_insert_statement_value
  "VALUES ()"
end

# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 302
def execute(sql, name = nil)
  log(sql, name) { @connection.query(sql) }
end

# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 207
def supports_index_sort_order?
  true
end

# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 193
def supports_migrations?
  true
end

# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 197
def supports_primary_key?
  true
end

# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 226
def supports_transaction_isolation?
  version[0] >= 5
end

# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 409
def table_exists?(name)
  return false unless name
  return true if tables(nil, nil, name).any?

  name          = name.to_s
  schema, table = name.split('.', 2)

  unless table # A table was provided without a schema
    table  = schema
    schema = nil
  end

  tables(nil, schema, table).any?
end

# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 211
def type_cast(value, column)
  case value
  when TrueClass
    1
  when FalseClass
    0
  else
    super
  end
end

# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 529
def type_to_sql(type, limit = nil, precision = nil, scale = nil)
  case type.to_s
  when 'binary'
    case limit
    when 0..0xfff;           "varbinary(#{limit})"
    when nil;                "blob"
    when 0x1000..0xffffffff; "blob(#{limit})"
    else raise(ActiveRecordError, "No binary type has character length #{limit}")
    end
  when 'integer'
    case limit
    when 1; 'tinyint'
    when 2; 'smallint'
    when 3; 'mediumint'
    when nil, 4, 11; 'int(11)'  # compatibility with MySQL default
    when 5..8; 'bigint'
    else raise(ActiveRecordError, "No integer type has byte size #{limit}")
    end
  when 'text'
    case limit
    when 0..0xff;               'tinytext'
    when nil, 0x100..0xffff;    'text'
    when 0x10000..0xffffff;     'mediumtext'
    when 0x1000000..0xffffffff; 'longtext'
    else raise(ActiveRecordError, "No text type has character length #{limit}")
    end
  else
    super
  end
end

# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 613
def valid_type?(type)
  !native_database_types[type].nil?
end