Class: Knj::Db

Inherits:
Object show all
Defined in:
lib/knj/knjdb/libknjdb.rb

Overview

A wrapper of several possible database-types.

Examples

db = Knj::Db.new(:type => “mysql”, :subtype => “mysql2”, :db => “mysql”, :user => “user”, :pass => “password”) mysql_table = db.tables name = mysql_table.name cols = mysql_table.columns

db = Knj::Db.new(:type => “sqlite3”, :path => “some_db.sqlite3”)

db.q(“SELECT * FROM users”) do |data|

print data[:name]

end

Defined Under Namespace

Classes: Dbtime, Dump, Idquery, Query_buffer, Revision, Sqlspecs

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(opts) ⇒ Db

Returns a new instance of Db.



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# File 'lib/knj/knjdb/libknjdb.rb', line 28

def initialize(opts)
  require "#{$knjpath}threadhandler"
  
  self.setOpts(opts) if opts != nil
  
  @int_types = ["int", "bigint", "tinyint", "smallint", "mediumint"]
  
  if !@opts[:threadsafe]
    require "monitor"
    @mutex = Monitor.new
  end
  
  @debug = @opts[:debug]
end

Dynamic Method Handling

This class handles dynamic methods through the method_missing method

#method_missing(method_name, *args) ⇒ Object

Proxies the method to the driver.

Examples

db.method_on_driver



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# File 'lib/knj/knjdb/libknjdb.rb', line 787

def method_missing(method_name, *args)
  self.conn_exec do |driver|
    if driver.respond_to?(method_name.to_sym)
      return driver.send(method_name, *args)
    end
  end
  
  raise "Method not found: #{method_name}"
end

Instance Attribute Details

#conn ⇒ Object (readonly)

Returns the value of attribute conn.



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# File 'lib/knj/knjdb/libknjdb.rb', line 26

def conn
  @conn
end

#conns ⇒ Object (readonly)

Returns the value of attribute conns.



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# File 'lib/knj/knjdb/libknjdb.rb', line 26

def conns
  @conns
end

#int_types ⇒ Object (readonly)

Returns the value of attribute int_types.



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# File 'lib/knj/knjdb/libknjdb.rb', line 26

def int_types
  @int_types
end

#opts ⇒ Object (readonly)

Returns the value of attribute opts.



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# File 'lib/knj/knjdb/libknjdb.rb', line 26

def opts
  @opts
end

Class Method Details

.const_missing(name) ⇒ Object

Autoloader.



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# File 'lib/knj/knjdb/libknjdb.rb', line 21

def self.const_missing(name)
  require "#{$knjpath}knjdb/#{name.to_s.downcase}"
  return Knj::Db.const_get(name)
end

Instance Method Details

#args ⇒ Object 



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# File 'lib/knj/knjdb/libknjdb.rb', line 43

def args
  return @opts
end

#clean ⇒ Object

Clean up various memory-stuff if possible.



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# File 'lib/knj/knjdb/libknjdb.rb', line 143

def clean
  if @conns
    @conns.objects.each do |data|
      data[:object].clean if data[:object].respond_to?("clean")
    end
  elsif @conn
    @conn.clean if @conn.respond_to?("clean")
  end
end

#clone_conn(args = {}) ⇒ Object

Clones the current database-connection with possible extra arguments.



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# File 'lib/knj/knjdb/libknjdb.rb', line 163

def clone_conn(args = {})
  conn = Knj::Db.new(@opts.clone.merge(args))
  
  if block_given?
    begin
      yield(conn)
    ensure
      conn.close
    end
    
    return nil
  else
    return conn
  end
end

#cloned_conn(args = nil, &block) ⇒ Object

Clones the connection, executes the given block and closes the connection again.

Examples

db.cloned_conn do |conn|

conn.q('SELCET * FROM users') do |data|
  print data[:name]
end

end



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# File 'lib/knj/knjdb/libknjdb.rb', line 564

def cloned_conn(args = nil, &block)
  clone_conn_args = {
    :threadsafe => false
  }
  
  clone_conn_args.merge!(args[:clone_args]) if args and args[:clone_args]
  dbconn = self.clone_conn(clone_conn_args)
  
  begin
    yield(dbconn)
  ensure
    dbconn.close
  end
end

#close ⇒ Object

The all driver-database-connections.



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# File 'lib/knj/knjdb/libknjdb.rb', line 154

def close
  @conn.close if @conn
  @conns.destroy if @conns
  
  @conn = nil
  @conns = nil
end

#col_table ⇒ Object

Returns the sign to be used for surrounding tables.



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# File 'lib/knj/knjdb/libknjdb.rb', line 768

def col_table
  return "`"
end

#cols ⇒ Object

Returns the columns-module and spawns it if it isnt already spawned.



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# File 'lib/knj/knjdb/libknjdb.rb', line 719

def cols
  if !@cols
    require "#{File.dirname(__FILE__)}/drivers/#{@opts[:type]}/knjdb_#{@opts[:type]}_columns" if (!@opts.key?(:require) or @opts[:require])
    @cols = Kernel.const_get("KnjDB_#{@opts[:type]}".to_sym).const_get(:Columns).new(
      :db => self
    )
  end
  
  return @cols
end

#conn_exec ⇒ Object

Returns a driver-object based on the current thread and free driver-objects.

Examples

db.conn_exec do |driver|

str = driver.escape('something̈́')

end



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# File 'lib/knj/knjdb/libknjdb.rb', line 484

def conn_exec
  if tcur = Thread.current and tcur[:knjdb]
    tid = self.__id__
    
    if tcur[:knjdb].key?(tid)
      yield(tcur[:knjdb][tid])
      return nil
    end
  end
  
  if @conns
    conn = @conns.get_and_lock
    
    begin
      yield(conn)
      return nil
    ensure
      @conns.free(conn)
    end
  elsif @conn
    @mutex.synchronize do
      yield(@conn)
      return nil
    end
  end
  
  raise "Could not figure out how to find a driver to use?"
end

#connect ⇒ Object

Actually connects to the database. This is useually done automatically.



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# File 'lib/knj/knjdb/libknjdb.rb', line 63

def connect
  if @opts[:threadsafe]
    @conns = Knj::Threadhandler.new
    
    @conns.on_spawn_new do
      self.spawn
    end
    
    @conns.on_inactive do |data|
      data[:obj].close
    end
    
    @conns.on_activate do |data|
      data[:obj].reconnect
    end
  else
    @conn = self.spawn
  end
end

#copy_to(db, args = {}) ⇒ Object

Copies the content of the current database to another instance of Knj::Db.



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# File 'lib/knj/knjdb/libknjdb.rb', line 180

def copy_to(db, args = {})
  data["tables"].each do |table|
    table_args = nil
    table_args = args["tables"][table["name"].to_s] if args and args["tables"] and args["tables"][table["name"].to_s]
    next if table_args and table_args["skip"]
    table.delete("indexes") if table.key?("indexes") and args["skip_indexes"]
    db.tables.create(table["name"], table)
    
    limit_from = 0
    limit_incr = 1000
    
    loop do
      ins_arr = []
      q_rows = self.select(table["name"], {}, {"limit_from" => limit_from, "limit_to" => limit_incr})
      while d_rows = q_rows.fetch
        col_args = nil
        
        if table_args and table_args["columns"]
          d_rows.each do |col_name, col_data|
            col_args = table_args["columns"][col_name.to_s] if table_args and table_args["columns"]
            d_rows[col_name] = "" if col_args and col_args["empty"]
          end
        end
        
        ins_arr << d_rows
      end
      
      break if ins_arr.empty?
      
      db.insert_multi(table["name"], ins_arr)
      limit_from += limit_incr
    end
  end
end

#data ⇒ Object

Returns the data of this database in a hash.

Examples

data = db.data tables_hash = data



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# File 'lib/knj/knjdb/libknjdb.rb', line 219

def data
  tables_ret = []
  tables.list.each do |name, table|
    tables_ret << table.data
  end
  
  return {
    "tables" => tables_ret
  }
end

#date_in(date_obj) ⇒ Object

Takes a valid date-db-string and converts it into a Knj::Datet.

Examples

db.date_in(‘2012-05-20 22:06:09’) #=> 2012-05-20 22:06:09 +0200



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# File 'lib/knj/knjdb/libknjdb.rb', line 694

def date_in(date_obj)
  conn_exec do |driver|
    if driver.respond_to?(:date_in)
      return driver.date_in(date_obj)
    end
  end
  
  return Knj::Datet.in(date_obj)
end

#date_out(date_obj = Knj::Datet.new, args = {}) ⇒ Object

Returns a string which can be used in SQL with the current driver.

Examples

str = db.date_out(Time.now) #=> “2012-05-20 22:06:09”



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# File 'lib/knj/knjdb/libknjdb.rb', line 681

def date_out(date_obj = Knj::Datet.new, args = {})
  conn_exec do |driver|
    if driver.respond_to?(:date_out)
      return driver.date_out(date_obj, args)
    end
  end
  
  return Knj::Datet.in(date_obj).dbstr(args)
end

#delete(tablename, arr_terms, args = nil) ⇒ Object

Deletes rows from the database.

Examples

db.delete(:users, => “Doe”)



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# File 'lib/knj/knjdb/libknjdb.rb', line 435

def delete(tablename, arr_terms, args = nil)
  self.conn_exec do |driver|
    sql = "DELETE FROM #{driver.escape_table}#{tablename}#{driver.escape_table}"
    
    if arr_terms != nil and !arr_terms.empty?
      sql << " WHERE #{self.makeWhere(arr_terms, driver)}"
    end
    
    return sql if args and args[:return_sql]
    driver.query(sql)
  end
  
  return nil
end

#enc_col ⇒ Object

Returns the sign for surrounding the string that should be used as a column.



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# File 'lib/knj/knjdb/libknjdb.rb', line 668

def enc_col
  if !@enc_col
    self.conn_exec do |driver|
      @enc_col = driver.escape_col
    end
  end
  
  return @enc_col
end

#enc_table ⇒ Object

Returns the sign for surrounding the string that should be used as a table.



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# File 'lib/knj/knjdb/libknjdb.rb', line 657

def enc_table
  if !@enc_table
    self.conn_exec do |driver|
      @enc_table = driver.escape_table
    end
  end
  
  return @enc_table
end

#esc_col(str) ⇒ Object

Escapes the given string to be used as a column.



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# File 'lib/knj/knjdb/libknjdb.rb', line 643

def esc_col(str)
  self.conn_exec do |driver|
    return driver.esc_col(str)
  end
end

#esc_table(str) ⇒ Object

Escapes the given string to be used as a table.



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# File 'lib/knj/knjdb/libknjdb.rb', line 650

def esc_table(str)
  self.conn_exec do |driver|
    return driver.esc_table(str)
  end
end

#escape(string) ⇒ Object Also known as: esc

Escapes a string to be safe-to-use in a query-string.

Examples

db.q(“INSERT INTO users (name) VALUES (‘#Knj::Db.dbdb.esc(’John’)‘)”)



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# File 'lib/knj/knjdb/libknjdb.rb', line 634

def escape(string)
  self.conn_exec do |driver|
    return driver.escape(string)
  end
end

#free_thread ⇒ Object

Frees the current driver from the current thread.



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# File 'lib/knj/knjdb/libknjdb.rb', line 131

def free_thread
  thread_cur = Thread.current
  tid = self.__id__
  
  if thread_cur[:knjdb] and thread_cur[:knjdb].key?(tid)
    db = thread_cur[:knjdb][tid]
    thread_cur[:knjdb].delete(tid)
    @conns.free(db) if @conns
  end
end

#get_and_register_thread ⇒ Object

Registers a driver to the current thread.



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# File 'lib/knj/knjdb/libknjdb.rb', line 106

def get_and_register_thread
  raise "KnjDB-object is not in threadding mode." if !@conns
  
  thread_cur = Thread.current
  tid = self.__id__
  thread_cur[:knjdb] = {} if !thread_cur[:knjdb]
  
  if thread_cur[:knjdb][tid]
    #An object has already been spawned - free that first to avoid endless "used" objects.
    self.free_thread
  end
  
  thread_cur[:knjdb][tid] = @conns.get_and_lock if !thread_cur[:knjdb][tid]
  
  #If block given then be ensure to free thread after yielding.
  if block_given?
    begin
      yield
    ensure
      self.free_thread
    end
  end
end

#indexes ⇒ Object

Returns the index-module and spawns it if it isnt already spawned.



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# File 'lib/knj/knjdb/libknjdb.rb', line 731

def indexes
  if !@indexes
    require "#{File.dirname(__FILE__)}/drivers/#{@opts[:type]}/knjdb_#{@opts[:type]}_indexes" if (!@opts.key?(:require) or @opts[:require])
    @indexes = Kernel.const_get("KnjDB_#{@opts[:type]}".to_sym).const_get(:Indexes).new(
      :db => self
    )
  end
  
  return @indexes
end

#insert(tablename, arr_insert, args = nil) ⇒ Object

Simply inserts data into a table.

Examples

db.insert(:users, => “John”, :lastname => “Doe”) id = db.insert(:users, => “John”, :lastname => “Doe”, :return_id => true) sql = db.insert(:users, => “John”, :lastname => “Doe”, :return_sql => true) #=> “INSERT INTO ‘users` (`name`, `lastname`) VALUES (’John’, ‘Doe’)”



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# File 'lib/knj/knjdb/libknjdb.rb', line 236

def insert(tablename, arr_insert, args = nil)
  self.conn_exec do |driver|
    sql = "INSERT INTO #{driver.escape_table}#{tablename.to_s}#{driver.escape_table}"
    
    if !arr_insert or arr_insert.empty?
      #This is the correct syntax for inserting a blank row in MySQL.
      sql << " VALUES ()"
    else
      sql << " ("
      
      first = true
      arr_insert.each do |key, value|
        if first
          first = false
        else
          sql << ", "
        end
        
        sql << "#{driver.escape_col}#{key.to_s}#{driver.escape_col}"
      end
      
      sql << ")  VALUES ("
      
      first = true
      arr_insert.each do |key, value|
        if first
          first = false
        else
          sql << ", "
        end
        
        sql << "#{driver.escape_val}#{driver.escape(value.to_s)}#{driver.escape_val}"
      end
      
      sql << ")"
    end
    
    return sql if args and args[:return_sql]
    driver.query(sql)
    return driver.lastID if args and args[:return_id]
    return nil
  end
end

#insert_multi(tablename, arr_hashes, args = nil) ⇒ Object

Simply and optimal insert multiple rows into a table in a single query. Uses the drivers functionality if supported or inserts each row manually.

Examples

db.insert_multi(:users, [

{:name => "John", :lastname => "Doe"},
{:name => "Kasper", :lastname => "Johansen"}

])



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# File 'lib/knj/knjdb/libknjdb.rb', line 287

def insert_multi(tablename, arr_hashes, args = nil)
  return false if arr_hashes.empty?
  
  self.conn_exec do |driver|
    if driver.respond_to?(:insert_multi)
      if args and args[:return_sql]
        return [driver.insert_multi(tablename, arr_hashes, args)]
      else
        return driver.insert_multi(tablename, arr_hashes, args)
      end
    else
      ret = [] if args and (args[:return_id] or args[:return_sql])
      arr_hashes.each do |hash|
        if ret
          ret << self.insert(tablename, hash, args)
        else
          self.insert(tablename, hash, args)
        end
      end
      
      if ret
        return ret
      else
        return nil
      end
    end
  end
end

#lastID ⇒ Object Also known as: last_id

Returns the last inserted ID.

Examples

id = db.last_id



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# File 'lib/knj/knjdb/libknjdb.rb', line 622

def lastID
  self.conn_exec do |driver|
    return driver.lastID
  end
end

#makeWhere(arr_terms, driver) ⇒ Object

Internally used to generate SQL.

Examples

sql = db.makeWhere(=> “Doe”, driver_obj)



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# File 'lib/knj/knjdb/libknjdb.rb', line 454

def makeWhere(arr_terms, driver)
  sql = ""
  
  first = true
  arr_terms.each do |key, value|
    if first
      first = false
    else
      sql << " AND "
    end
    
    if value.is_a?(Array)
      raise "Array for column '#{key}' was empty." if value.empty?
      sql << "#{driver.escape_col}#{key}#{driver.escape_col} IN (#{Knj::ArrayExt.join(:arr => value, :sep => ",", :surr => "'", :callback => proc{|ele| self.esc(ele)})})"
    elsif value.is_a?(Hash)
      raise "Dont know how to handle hash."
    else
      sql << "#{driver.escape_col}#{key}#{driver.escape_col} = #{driver.escape_val}#{driver.escape(value)}#{driver.escape_val}"
    end
  end
  
  return sql
end

#optimize(args = nil) ⇒ Object

Optimizes all tables in the database.



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# File 'lib/knj/knjdb/libknjdb.rb', line 773

def optimize(args = nil)
  STDOUT.puts "Beginning optimization of database." if @debug or (args and args[:debug])
  self.tables.list do |table|
    STDOUT.puts "Optimizing table: '#{table.name}'." if @debug or (args and args[:debug])
    table.optimize
  end
  
  return nil
end

#q(str, args = nil, &block) ⇒ Object

Executes a query and returns the result. If a block is given the result is iterated over that block instead and it returns nil.

Examples

db.q(‘SELECT * FROM users’) do |data|

print data[:name]

end



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# File 'lib/knj/knjdb/libknjdb.rb', line 585

def q(str, args = nil, &block)
  #If the query should be executed in a new connection unbuffered.
  if args
    if args[:cloned_ubuf]
      raise "No block given." if !block
      
      self.cloned_conn(:clone_args => args[:clone_args]) do |cloned_conn|
        ret = cloned_conn.query_ubuf(str)
        ret.each(&block)
      end
      
      return nil
    else
      raise "Invalid arguments given: '#{args}'."
    end
  end
  
  ret = self.query(str)
  
  if block
    ret.each(&block)
    return nil
  end
  
  return ret
end

#q_buffer(&block) ⇒ Object

Yields a query-buffer and flushes at the end of the block given.



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# File 'lib/knj/knjdb/libknjdb.rb', line 613

def q_buffer(&block)
  Knj::Db::Query_buffer.new(:db => self, &block)
  return nil
end

#query(string) ⇒ Object

Executes a query and returns the result.

Examples

res = db.query(‘SELECT * FROM users’) while data = res.fetch

print data[:name]

end



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# File 'lib/knj/knjdb/libknjdb.rb', line 520

def query(string)
  if @debug
    print "SQL: #{string}\n"
    
    if @debug.is_a?(Fixnum) and @debug >= 2
      print caller.join("\n")
      print "\n"
    end
  end
  
  self.conn_exec do |driver|
    return driver.query(string)
  end
end

#query_ubuf(string, &block) ⇒ Object

Execute an ubuffered query and returns the result.

Examples

db.query_ubuf(‘SELECT * FROM users’) do |data|

print data[:name]

end



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# File 'lib/knj/knjdb/libknjdb.rb', line 541

def query_ubuf(string, &block)
  ret = nil
  
  self.conn_exec do |driver|
    ret = driver.query_ubuf(string, &block)
  end
  
  if block
    ret.each(&block)
    return nil
  end
  
  return ret
end

#select(tablename, arr_terms = nil, args = nil, &block) ⇒ Object

Makes a select from the given arguments: table-name, where-terms and other arguments as limits and orders. Also takes a block to avoid raping of memory.



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# File 'lib/knj/knjdb/libknjdb.rb', line 352

def select(tablename, arr_terms = nil, args = nil, &block)
  #Set up vars.
  sql = ""
  args_q = nil
  select_sql = "*"
  
  #Give 'cloned_ubuf' argument to 'q'-method.
  if args and args[:cloned_ubuf]
    args_q = {:cloned_ubuf => true}
  end
  
  #Set up IDQuery-stuff if that is given in arguments.
  if args and args[:idquery]
    if args[:idquery] == true
      select_sql = "`id`"
      col = :id
    else
      select_sql = "`#{self.esc_col(args[:idquery])}`"
      col = args[:idquery]
    end
  end
  
  #Get the driver and generate SQL.
  self.conn_exec do |driver|
    sql = "SELECT #{select_sql} FROM #{driver.escape_table}#{tablename.to_s}#{driver.escape_table}"
    
    if arr_terms != nil and !arr_terms.empty?
      sql << " WHERE #{self.makeWhere(arr_terms, driver)}"
    end
    
    if args != nil
      if args["orderby"]
        sql << " ORDER BY #{args["orderby"]}"
      end
      
      if args["limit"]
        sql << " LIMIT #{args["limit"]}"
      end
      
      if args["limit_from"] and args["limit_to"]
        raise "'limit_from' was not numeric: '#{args["limit_from"]}'." if !Knj::Php.is_numeric(args["limit_from"])
        raise "'limit_to' was not numeric: '#{args["limit_to"]}'." if !Knj::Php.is_numeric(args["limit_to"])
        sql << " LIMIT #{args["limit_from"]}, #{args["limit_to"]}"
      end
    end
  end
  
  #Do IDQuery if given in arguments.
  if args and args[:idquery]
    res = Knj::Db::Idquery.new(:db => self, :table => tablename, :query => sql, :col => col, &block)
  else
    res = self.q(sql, args_q, &block)
  end
  
  #Return result if a block wasnt given.
  if block
    return nil
  else
    return res
  end
end

#setOpts(arr_opts) ⇒ Object 



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# File 'lib/knj/knjdb/libknjdb.rb', line 47

def setOpts(arr_opts)
  @opts = {}
  arr_opts.each do |key, val|
    @opts[key.to_sym] = val
  end
  
  if RUBY_PLATFORM == "java"
    @opts[:subtype] = "java"
  elsif @opts[:type] == "sqlite3" and RUBY_PLATFORM.index("mswin32") != nil
    @opts[:subtype] = "ironruby"
  end
  
  self.connect
end

#single(tablename, arr_terms = nil, args = {}) ⇒ Object Also known as: selectsingle

Returns a single row from a database.

Examples

row = db.single(:users, => “Doe”)



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# File 'lib/knj/knjdb/libknjdb.rb', line 418

def single(tablename, arr_terms = nil, args = {})
  args["limit"] = 1
  
  #Experienced very weird memory leak if this was not done by block. Maybe bug in Ruby 1.9.2? - knj
  self.select(tablename, arr_terms, args) do |data|
    return data
  end
  
  return false
end

#spawn ⇒ Object

Spawns a new driver (useally done automatically).

Examples

driver_instance = db.spawn



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# File 'lib/knj/knjdb/libknjdb.rb', line 86

def spawn
  raise "No type given (#{@opts.keys.join(",")})." if !@opts[:type]
  
  fpaths = [
    "drivers/#{@opts[:type]}/knjdb_#{@opts[:type]}.rb",
    "libknjdb_#{@opts[:type]}.rb"
  ]
  fpaths.each do |fpath|
    rpath = "#{File.dirname(__FILE__)}/#{fpath}"
    
    if (!@opts.key?(:require) or @opts[:require]) and File.exists?(rpath)
      require rpath
      break
    end
  end
  
  return Kernel.const_get("KnjDB_#{@opts[:type]}").new(self)
end

#sqlspecs ⇒ Object

Returns the SQLSpec-module and spawns it if it isnt already spawned.



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# File 'lib/knj/knjdb/libknjdb.rb', line 743

def sqlspecs
  if !@sqlspecs
    require "#{File.dirname(__FILE__)}/drivers/#{@opts[:type]}/knjdb_#{@opts[:type]}_sqlspecs" if (!@opts.key?(:require) or @opts[:require])
    @sqlspecs = Kernel.const_get("KnjDB_#{@opts[:type]}".to_sym).const_get(:Sqlspecs).new(
      :db => self
    )
  end
  
  return @sqlspecs
end

#tables ⇒ Object

Returns the table-module and spawns it if it isnt already spawned.



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# File 'lib/knj/knjdb/libknjdb.rb', line 705

def tables
  conn_exec do |driver|
    if !@tables
      require "#{File.dirname(__FILE__)}/drivers/#{@opts[:type]}/knjdb_#{@opts[:type]}_tables" if (!@opts.key?(:require) or @opts[:require])
      @tables = Kernel.const_get("KnjDB_#{@opts[:type]}".to_sym).const_get(:Tables).new(
        :db => self
      )
    end
    
    return @tables
  end
end

#transaction(&block) ⇒ Object

Beings a transaction and commits when the block ends.

Examples

db.transaction do |db|

db.insert(:users, {:name => "John"})
db.insert(:users, {:name => "Kasper"})

end



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# File 'lib/knj/knjdb/libknjdb.rb', line 761

def transaction(&block)
  self.conn_exec do |driver|
    driver.transaction(&block)
  end
end

#update(tablename, arr_update, arr_terms = {}, args = nil) ⇒ Object

Simple updates rows.

Examples

db.update(:users, => “John”, => “Doe”)



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# File 'lib/knj/knjdb/libknjdb.rb', line 320

def update(tablename, arr_update, arr_terms = {}, args = nil)
  return false if arr_update.empty?
  
  self.conn_exec do |driver|
    sql = ""
    sql << "UPDATE #{driver.escape_col}#{tablename.to_s}#{driver.escape_col} SET "
    
    first = true
    arr_update.each do |key, value|
      if first
        first = false
      else
        sql << ", "
      end
      
      #Convert dates to valid dbstr.
      value = self.date_out(value) if value.is_a?(Knj::Datet) or value.is_a?(Time)
      
      sql << "#{driver.escape_col}#{key.to_s}#{driver.escape_col} = "
      sql << "#{driver.escape_val}#{driver.escape(value.to_s)}#{driver.escape_val}"
    end
    
    if arr_terms and arr_terms.length > 0
      sql << " WHERE #{self.makeWhere(arr_terms, driver)}"
    end
    
    return sql if args and args[:return_sql]
    driver.query(sql)
  end
end