Class: Og::PsqlAdapter

Inherits:
Adapter show all
Defined in:
lib/og/adapters/psql.rb

Overview

The PostgreSQL adapter. This adapter communicates with an PostgreSQL rdbms. For extra documentation see lib/og/adapter.rb

Instance Attribute Summary

Attributes inherited from Adapter

#typemap

Class Method Summary collapse

Instance Method Summary collapse

Methods inherited from Adapter

#create_fields, encode, #eval_og_insert, #eval_og_read, #eval_og_update, for_name, #initialize, join_table, parse_date, parse_timestamp, #props_for_insert, table

Constructor Details

This class inherits a constructor from Og::Adapter

Class Method Details

.date(date) ⇒ Object 



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# File 'lib/og/adapters/psql.rb', line 29

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

.escape(str) ⇒ Object 



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# File 'lib/og/adapters/psql.rb', line 19

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

.timestamp(time = Time.now) ⇒ Object 



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# File 'lib/og/adapters/psql.rb', line 24

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

Instance Method Details

#calc_field_index(klass, db) ⇒ Object 



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# File 'lib/og/adapters/psql.rb', line 100

def calc_field_index(klass, db)
	res = db.query "SELECT * FROM #{klass::DBTABLE} LIMIT 1"
	meta = db.managed_classes[klass]

	for field in res.fields
		meta.field_index[field] = res.fieldnum(field)
	end

ensure
	res.clear if res
end

#create_db(database, user = nil, password = nil) ⇒ Object 



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# File 'lib/og/adapters/psql.rb', line 70

def create_db(database, user = nil, password = nil)
	`createdb #{database} -U #{user}`
	super
end

#create_table(klass, db) ⇒ Object 



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# File 'lib/og/adapters/psql.rb', line 112

def create_table(klass, db)
	conn = db.get_connection

	fields = create_fields(klass)

	sql = "CREATE TABLE #{klass::DBTABLE} (#{fields.join(', ')}"
	
	# Create table constrains
	
	if klass.__meta and constrains = klass.__meta[:sql_constrain]
		sql << ", #{constrains.join(', ')}"
	end
	
	sql << ") WITHOUT OIDS;"
	
	# Create indices
	
	if klass.__meta and indices = klass.__meta[:sql_index]
		for data in indices
			idx, options = *data
			idx = idx.to_s
			pre_sql, post_sql = options[:pre], options[:post]
			idxname = idx.gsub(/ /, "").gsub(/,/, "_").gsub(/\(.*\)/, "")
			sql << " CREATE #{pre_sql} INDEX #{klass::DBTABLE}_#{idxname}_idx #{post_sql} ON #{klass::DBTABLE} (#{idx});"  
		end
	end

	begin
		conn.store.exec(sql).clear
		Logger.info "Created table '#{klass::DBTABLE}'."
	rescue => ex
		# gmosx: any idea how to better test this?
		if ex.to_s =~ /relation .* already exists/i
			Logger.debug 'Table already exists' if $DBG
			return
		else
			raise
		end
	end

	# Create join tables if needed. Join tables are used in
	# 'many_to_many' relations.
	
	if klass.__meta and joins = klass.__meta[:sql_join] 
		for data in joins
			# the class to join to and some options.
			join_class, options = *data
			
			# gmosx: dont use DBTABLE here, perhaps the join class
			# is not managed yet.
			join_table = "#{self.class.join_table(klass, join_class)}"
			join_src = "#{self.class.encode(klass)}_oid"
			join_dst = "#{self.class.encode(join_class)}_oid"
			begin
				conn.store.exec("CREATE TABLE #{join_table} ( key1 integer NOT NULL, key2 integer NOT NULL )").clear
				conn.store.exec("CREATE INDEX #{join_table}_key1_idx ON #{join_table} (key1)").clear
				conn.store.exec("CREATE INDEX #{join_table}_key2_idx ON #{join_table} (key2)").clear
			rescue => ex
				# gmosx: any idea how to better test this?
				if ex.to_s =~ /relation .* already exists/i
					Logger.debug "Join table already exists" if $DBG
				else
					raise
				end
			end
		end
	end

ensure
	db.put_connection
end

#drop_db(database, user = nil, password = nil) ⇒ Object 



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# File 'lib/og/adapters/psql.rb', line 75

def drop_db(database, user = nil, password = nil)
	`dropdb #{database} -U #{user}`
	super
end

#drop_table(klass) ⇒ Object 



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# File 'lib/og/adapters/psql.rb', line 184

def drop_table(klass)
	super
	exec "DROP SEQUENCE #{klass::DBSEQ}"		
end

#eval_og_oid(klass) ⇒ Object

Generate the property for oid.



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# File 'lib/og/adapters/psql.rb', line 191

def eval_og_oid(klass)
	klass.class_eval %{
		prop_accessor :oid, Fixnum, :sql => 'serial PRIMARY KEY'
	}
end

#insert_code(klass, db, pre_cb, post_cb) ⇒ Object 



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# File 'lib/og/adapters/psql.rb', line 80

def insert_code(klass, db, pre_cb, post_cb)
	props = props_for_insert(klass)
	values = props.collect { |p| write_prop(p) }.join(',') 

	sql = "INSERT INTO #{klass::DBTABLE} (#{props.collect {|p| p.name}.join(',')}) VALUES (#{values})"

	%{
		#{pre_cb}
		res = conn.store.exec("SELECT nextval('#{klass::DBSEQ}')")
		@oid = res.getvalue(0, 0).to_i
		res.clear
		conn.exec "#{sql}"
		#{post_cb}
	}
end

#new_connection(db) ⇒ Object 



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# File 'lib/og/adapters/psql.rb', line 96

def new_connection(db)
	return Og::PsqlConnection.new(db)
end

#read_prop(p, idx) ⇒ Object 



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# File 'lib/og/adapters/psql.rb', line 52

def read_prop(p, idx)
	if p.klass.ancestors.include?(Integer)
		return "res.getvalue(tuple, #{idx}).to_i()"
	elsif p.klass.ancestors.include?(Float)
		return "res.getvalue(tuple, #{idx}).to_f()"
	elsif p.klass.ancestors.include?(String)
		return "res.getvalue(tuple, #{idx})"
	elsif p.klass.ancestors.include?(Time)
		return "#{self.class}.parse_timestamp(res.getvalue(tuple, #{idx}))"
	elsif p.klass.ancestors.include?(Date)
		return "#{self.class}.parse_date(res.getvalue(tuple, #{idx}))"
	elsif p.klass.ancestors.include?(TrueClass)
		return %|('t' == res.getvalue(tuple, #{idx}))|
	else 
		return "YAML::load(res.getvalue(tuple, #{idx}))"
	end		
end

#write_prop(p) ⇒ Object 



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# File 'lib/og/adapters/psql.rb', line 34

def write_prop(p)
	if p.klass.ancestors.include?(Integer)
		return "#\{@#{p.symbol} || 'NULL'\}"
	elsif p.klass.ancestors.include?(Float)
		return "#\{@#{p.symbol} || 'NULL'\}"		
	elsif p.klass.ancestors.include?(String)
		return "'#\{#{self.class}.escape(@#{p.symbol})\}'"
	elsif p.klass.ancestors.include?(Time)
		return %|#\{@#{p.symbol} ? "'#\{#{self.class}.timestamp(@#{p.symbol})\}'" : 'NULL'\}|
	elsif p.klass.ancestors.include?(Date)
		return %|#\{@#{p.symbol} ? "'#\{#{self.class}.date(@#{p.symbol})\}'" : 'NULL'\}|
	elsif p.klass.ancestors.include?(TrueClass)
		return "#\{@#{p.symbol} ? \"'t'\" : 'NULL' \}"
	else 
		return %|#\{@#{p.symbol} ? "'#\{#{self.class}.escape(@#{p.symbol}.to_yaml)\}'" : "''"\}|
	end
end