Class: DohDb::Handle

Inherits:
Object show all
Defined in:
lib/doh/mysql/handle.rb

Instance Method Summary collapse

Constructor Details

#initialize(mysqlh, row_builder = nil) ⇒ Handle

Returns a new instance of Handle.



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# File 'lib/doh/mysql/handle.rb', line 12

def initialize(mysqlh, row_builder = nil)
  @mysqlh = mysqlh
  @row_builder = row_builder || TypedRowBuilder.new
end

Instance Method Details

#close ⇒ Object 



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# File 'lib/doh/mysql/handle.rb', line 17

def close
  unless closed?
    dohlog.info("closing raw mysql handle: #@mysqlh")
    @mysqlh.close
    @mysqlh = nil
  end
end

#closed? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/doh/mysql/handle.rb', line 25

def closed?
  @mysqlh.nil?
end

#insert(statement) ⇒ Object 



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# File 'lib/doh/mysql/handle.rb', line 54

def insert(statement)
  generic_query(statement)
  retval = @mysqlh.insert_id
  dohlog.info("insert_id was #{retval}")
  retval
end

#insert_hash(hash, table, ignore = nil) ⇒ Object 



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# File 'lib/doh/mysql/handle.rb', line 61

def insert_hash(hash, table, ignore = nil)
  if ignore then keyword = 'INSERT IGNORE' else keyword = 'INSERT' end
  insert_hash_helper(hash, table, keyword)
end

#multi_select(statement_infos, dflt_row_builder = nil) ⇒ Object 



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# File 'lib/doh/mysql/handle.rb', line 143

def multi_select(statement_infos, dflt_row_builder = nil)
  statements = []
  row_builders = []
  statement_infos.each do |info|
    if info.is_a?(Array)
      statements.push(info.first)
      row_builders.push(info.last)
    else
      statements.push(info)
      row_builders.push(nil)
    end
  end
  sqlstr = statements.join(';')

  dohlog.info(sqlstr)
  @mysqlh.query(sqlstr)
  retval = []
  while true
    custom_builder = row_builders.shift
    if @mysqlh.field_count > 0
      result_set = @mysqlh.store_result
      dohlog.info("selected #{result_set.num_rows} rows")
      rows = get_row_builder(custom_builder || dflt_row_builder).build_rows(result_set)
      result_set.free
      retval.push(rows)
    end
    break unless @mysqlh.next_result
  end
  retval
rescue Exception => excpt
  dohlog.error("caught exception during query: #{sqlstr}", excpt)
  raise
end

#query(statement) ⇒ Object 



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# File 'lib/doh/mysql/handle.rb', line 29

def query(statement)
  generic_query(statement)
  retval = @mysqlh.affected_rows
  dohlog.info("affected #{retval} rows")
  retval
end

#replace_hash(hash, table) ⇒ Object 



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# File 'lib/doh/mysql/handle.rb', line 66

def replace_hash(hash, table)
  insert_hash_helper(hash, table, 'REPLACE')
end

#select(statement, row_builder = nil) ⇒ Object

The most generic form of select. It calls to_s on the statement object to facilitate the use of sql builder objects.



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# File 'lib/doh/mysql/handle.rb', line 72

def select(statement, row_builder = nil)
  result_set = generic_query(statement)
  dohlog.info("selected #{result_set.num_rows} rows")
  rows = get_row_builder(row_builder).build_rows(result_set)
  result_set.free
  rows
end

#select_field(statement, row_builder = nil) ⇒ Object

Simple convenience wrapper around select_row. Returns the first (and typically, the only) field from the selected row.



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# File 'lib/doh/mysql/handle.rb', line 100

def select_field(statement, row_builder = nil)
  select_row(statement, row_builder).at(0)
end

#select_list(statement, row_builder = nil) ⇒ Object

Returns an array of the first (and typically, the only) field of every row in the result set.



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# File 'lib/doh/mysql/handle.rb', line 139

def select_list(statement, row_builder = nil)
  select(statement, row_builder).collect { |row| row.at(0) }
end

#select_optional_field(statement, row_builder = nil) ⇒ Object

Simple convenience wrapper around select_optional_row. Returns the first (and typically, the only) field from the selected row, if any, or nil.



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# File 'lib/doh/mysql/handle.rb', line 106

def select_optional_field(statement, row_builder = nil)
  row = select_optional_row(statement, row_builder)
  row && row.at(0)
end

#select_optional_row(statement, row_builder = nil) ⇒ Object

Simple convenience wrapper around the generic select call. Throws an exception unless the result set is empty or a single row. Returns nil if the result set is empty, or the row selected.

Raises:



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# File 'lib/doh/mysql/handle.rb', line 92

def select_optional_row(statement, row_builder = nil)
  rows = select(statement, row_builder)
  raise UnexpectedQueryResult, "selected #{rows.size} rows; expected 0 or 1" if rows.size > 1
  if rows.empty? then nil else rows[0] end
end

#select_row(statement, row_builder = nil) ⇒ Object

Simple convenience wrapper around the generic select call. Throws an exception unless the result set is a single row. Returns the row selected.

Raises:



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# File 'lib/doh/mysql/handle.rb', line 83

def select_row(statement, row_builder = nil)
  rows = select(statement, row_builder)
  raise UnexpectedQueryResult, "selected #{rows.size} rows; expected 1" unless rows.size == 1
  rows[0]
end

#select_transpose(statement, row_builder = nil) ⇒ Object

Rows in the result set must have 2 or more fields. If there are 2 fields, returns a hash where each key is the first field in the result set, and the value is the second field. If there are more than 2 fields, returns a hash where each key is the first field in the result set, and the value is the row itself, as a Hash, and without the field used as a key.



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# File 'lib/doh/mysql/handle.rb', line 115

def select_transpose(statement, row_builder = nil)
  rows = select(statement, row_builder)
  return {} if rows.empty?
  field_count = rows.first.size
  if field_count < 2
    raise UnexpectedQueryResult, "must select at least 2 fields in order to transpose"
  elsif field_count == 2
    rows.build_hash { |row| [row.at(0), row.at(1)] }
  else
    key_field = rows.first.keys.first
    rows.build_hash do |row|
      value = row.to_h
      value.delete(key_field)
      [row.at(0), value]
    end
  end
end

#select_values(statement, row_builder = nil) ⇒ Object

Returns an array of arrays, where the individual arrays contain just the values from each database row – they lack field names.



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# File 'lib/doh/mysql/handle.rb', line 134

def select_values(statement, row_builder = nil)
  select(statement, row_builder).collect { |row| row.values }
end

#update(statement) ⇒ Object 



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# File 'lib/doh/mysql/handle.rb', line 36

def update(statement)
  generic_query(statement)
  retval = @mysqlh.affected_rows
  dohlog.info("updated #{retval} rows")
  retval
end

#update_hash(hash, table, primary_key_value, primary_key_name) ⇒ Object 



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# File 'lib/doh/mysql/handle.rb', line 49

def update_hash(hash, table, primary_key_value, primary_key_name)
  items = hash.keys.collect {|key| key + ' = ' + hash[key].to_sql}
  query("UPDATE #{table} SET #{items.join(', ')} WHERE #{primary_key_name} = #{primary_key_value.to_sql}")
end

#update_row(statement) ⇒ Object

Raises:



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# File 'lib/doh/mysql/handle.rb', line 43

def update_row(statement)
  retval = update(statement)
  raise UnexpectedQueryResult, "updated #{retval} rows; expected 1" unless retval == 1
  retval
end