Module: N::DbUtils

Included in:
DbConnection
Defined in:
lib/n/db/psql.rb,
lib/n/db/mysql.rb,
lib/n/db/utils.rb

Overview

DbUtils

A collection of Database utilities. Additional backend specific utilities are defined in the backend implementations.

Class Method Summary collapse

Class Method Details

.escape(str) ⇒ Object

Escape an sql string



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# File 'lib/n/db/psql.rb', line 25

def self.escape(str)
	return nil unless str
	return PGconn.escape(str)
end

.escape_bytes(bytes) ⇒ Object

Escape bytes



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# File 'lib/n/db/psql.rb', line 32

def self.escape_bytes(bytes)
	return nil unless bytes
	return PGconn.escape_bytea(bytes)
end

.parse_sql_date(str) ⇒ Object

Input YYYY-mm-dd



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# File 'lib/n/db/psql.rb', line 70

def self.parse_sql_date(str)
	return nil unless str
	return Date.strptime(str)
end

.parse_sql_timestamp(str) ⇒ Object

Parse sql datetime



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# File 'lib/n/db/psql.rb', line 64

def self.parse_sql_timestamp(str)
	return Time.parse(str)		
end

.read_prop(p) ⇒ Object

Return an evaluator for reading the property No need to optimize this, used only to precalculate code.



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# File 'lib/n/db/psql.rb', line 78

def self.read_prop(p, idx)
	case p.klass.to_s
		when Fixnum.name
			return "rows.getvalue(tuple, #{idx}).to_i()"
		when Float.name
			return "rows.getvalue(tuple, #{idx}).to_f()"
		when Time.name
			return "N::DbUtils.parse_sql_timestamp(rows.getvalue(tuple, #{idx}))"
		when Date.name
			return "N::DbUtils.parse_sql_date(rows.getvalue(tuple, #{idx}))"
		when TrueClass.name
			return "('true' == rows.getvalue(tuple, #{idx}))"
		when Object.name
			return "Marshal.load(N::DbUtils.unescape_bytes(rows.getvalue(tuple, #{idx})))"
		when Array.name
			return "Marshal.load(N::DbUtils.unescape_bytes(rows.getvalue(tuple, #{idx})))"
		when Hash.name
			return "Marshal.load(N::DbUtils.unescape_bytes(rows.getvalue(tuple, #{idx})))"
		else # String 
			return "rows.getvalue(tuple, #{idx})"
	end		
end

.sql_date(date) ⇒ Object

Output YYY-mm-dd



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# File 'lib/n/db/psql.rb', line 55

def self.sql_date(date)
	return nil unless date
	return "#{date.year}-#{date.month}-#{date.mday}" 
end

.sql_table(klass) ⇒ Object

The name of the SQL table where entities of this class are stored. The Module separators are replaced with _ and NOT stripped out so that we can convert back to the original notation if needed.



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# File 'lib/n/db/utils.rb', line 41

def self.sql_table(klass)
	return "#{klass}".gsub(/::/, "_").downcase
end

.sql_timestamp(time = Time.now) ⇒ Object

Convert a ruby time to an sql timestamp.



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# File 'lib/n/db/psql.rb', line 48

def self.sql_timestamp(time = Time.now)
	return nil unless time
	return time.strftime("%Y-%m-%d %H:%M:%S")
end

.unescape_bytes(bytes) ⇒ Object

Unescape bytes FIXME: optimize this! Even better integrate this in the libpq library, or find out why the default method doesnt work.



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# File 'lib/n/db/psql.rb', line 42

def self.unescape_bytes(bytes)
	return bytes.gsub(/(\\\d+)/) { |m| m.gsub(/\\/, "").oct.chr }
end

.write_prop(p) ⇒ Object

Return an sql string evaluator for the property. No need to optimize this, used only to precalculate code.

FIXME: add extra handling for float.



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# File 'lib/n/db/utils.rb', line 74

def self.write_prop(p)
	if String == p.klass
		return "'#\{DbUtils.escape(@#{p.symbol})\}'"
	elsif Time == p.klass
		return %|#\{@#{p.symbol} ? "'#\{DbUtils.sql_timestamp(@#{p.symbol})\}'" : 'NULL'\}|
	elsif Date == p.klass
		return %|#\{@#{p.symbol} ? "'#\{DbUtils.sql_date(@#{p.symbol})\}'" : 'NULL'\}|
	elsif Object == p.klass or Array == p.klass or Hash == p.klass
		#return "'#\{DbUtils.escape_bytes(Marshal.dump(@#{p.symbol}))\}'"
		return "'#\{DbUtils.escape_bytes(Marshal.dump(@#{p.symbol}))\}'"
	else
		# Fixnum, TrueClass
		return "#\{@#{p.symbol} || 'NULL'\}"
	end
end