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# oracle_adapter.rb -- ActiveRecord adapter for Oracle 8i, 9i, 10g
#
# Original author: Graham Jenkins
#
# Current maintainer: Michael Schoen <schoenm@earthlink.net>
#
#########################################################################
#
# Implementation notes:
# 1. Redefines (safely) a method in ActiveRecord to make it possible to
# implement an autonumbering solution for Oracle.
# 2. The OCI8 driver is patched to properly handle values for LONG and
# TIMESTAMP columns. The driver-author has indicated that a future
# release of the driver will obviate this patch.
# 3. LOB support is implemented through an after_save callback.
# 4. Oracle does not offer native LIMIT and OFFSET options; this
# functionality is mimiced through the use of nested selects.
# See http://asktom.oracle.com/pls/ask/f?p=4950:8:::::F4950_P8_DISPLAYID:127412348064
#
# Do what you want with this code, at your own peril, but if any
# significant portion of my code remains then please acknowledge my
# contribution.
# portions Copyright 2005 Graham Jenkins
require 'active_record/connection_adapters/abstract_adapter'
require 'delegate'
begin
require_library_or_gem 'oci8' unless self.class.const_defined? :OCI8
module ActiveRecord
class Base
def self.oracle_connection(config) #:nodoc:
# Use OCI8AutoRecover instead of normal OCI8 driver.
ConnectionAdapters::OracleAdapter.new OCI8AutoRecover.new(config), logger
end
# for backwards-compatibility
def self.oci_connection(config) #:nodoc:
config[:database] = config[:host]
self.oracle_connection(config)
end
# After setting large objects to empty, select the OCI8::LOB
# and write back the data.
after_save :write_lobs
def write_lobs() #:nodoc:
if connection.is_a?(ConnectionAdapters::OracleAdapter)
self.class.columns.select { |c| c.sql_type =~ /LOB$/i }.each { |c|
value = self[c.name]
value = value.to_yaml if unserializable_attribute?(c.name, c)
next if value.nil? || (value == '')
lob = connection.select_one(
"SELECT #{c.name} FROM #{self.class.table_name} WHERE #{self.class.primary_key} = #{quote_value(id)}",
'Writable Large Object')[c.name]
lob.write value
}
end
end
private :write_lobs
end
module ConnectionAdapters #:nodoc:
class OracleColumn < Column #:nodoc:
def type_cast(value)
return guess_date_or_time(value) if type == :datetime && OracleAdapter.emulate_dates
super
end
private
def simplified_type(field_type)
return :boolean if OracleAdapter.emulate_booleans && field_type == 'NUMBER(1)'
case field_type
when /date|time/i then :datetime
else super
end
end
def guess_date_or_time(value)
(value.hour == 0 and value.min == 0 and value.sec == 0) ?
Date.new(value.year, value.month, value.day) : value
end
end
# This is an Oracle/OCI adapter for the ActiveRecord persistence
# framework. It relies upon the OCI8 driver, which works with Oracle 8i
# and above. Most recent development has been on Debian Linux against
# a 10g database, ActiveRecord 1.12.1 and OCI8 0.1.13.
# See: http://rubyforge.org/projects/ruby-oci8/
#
# Usage notes:
# * Key generation assumes a "${table_name}_seq" sequence is available
# for all tables; the sequence name can be changed using
# ActiveRecord::Base.set_sequence_name. When using Migrations, these
# sequences are created automatically.
# * Oracle uses DATE or TIMESTAMP datatypes for both dates and times.
# Consequently some hacks are employed to map data back to Date or Time
# in Ruby. If the column_name ends in _time it's created as a Ruby Time.
# Else if the hours/minutes/seconds are 0, I make it a Ruby Date. Else
# it's a Ruby Time. This is a bit nasty - but if you use Duck Typing
# you'll probably not care very much. In 9i and up it's tempting to
# map DATE to Date and TIMESTAMP to Time, but too many databases use
# DATE for both. Timezones and sub-second precision on timestamps are
# not supported.
# * Default values that are functions (such as "SYSDATE") are not
# supported. This is a restriction of the way ActiveRecord supports
# default values.
# * Support for Oracle8 is limited by Rails' use of ANSI join syntax, which
# is supported in Oracle9i and later. You will need to use #finder_sql for
# has_and_belongs_to_many associations to run against Oracle8.
#
# Required parameters:
#
# * <tt>:username</tt>
# * <tt>:password</tt>
# * <tt>:database</tt>
class OracleAdapter < AbstractAdapter
@@emulate_booleans = true
cattr_accessor :emulate_booleans
@@emulate_dates = false
cattr_accessor :emulate_dates
def adapter_name #:nodoc:
'Oracle'
end
def supports_migrations? #:nodoc:
true
end
def native_database_types #:nodoc:
{
:primary_key => "NUMBER(38) NOT NULL PRIMARY KEY",
:string => { :name => "VARCHAR2", :limit => 255 },
:text => { :name => "CLOB" },
:integer => { :name => "NUMBER", :limit => 38 },
:float => { :name => "NUMBER" },
:decimal => { :name => "DECIMAL" },
:datetime => { :name => "DATE" },
:timestamp => { :name => "DATE" },
:time => { :name => "DATE" },
:date => { :name => "DATE" },
:binary => { :name => "BLOB" },
:boolean => { :name => "NUMBER", :limit => 1 }
}
end
def table_alias_length
30
end
# QUOTING ==================================================
#
# see: abstract/quoting.rb
# camelCase column names need to be quoted; not that anyone using Oracle
# would really do this, but handling this case means we pass the test...
def quote_column_name(name) #:nodoc:
name.to_s =~ /[A-Z]/ ? "\"#{name}\"" : name
end
def quote_string(s) #:nodoc:
s.gsub(/'/, "''")
end
def quote(value, column = nil) #:nodoc:
if value && column && [:text, :binary].include?(column.type)
%Q{empty_#{ column.sql_type.downcase rescue 'blob' }()}
else
super
end
end
def quoted_true
"1"
end
def quoted_false
"0"
end
# CONNECTION MANAGEMENT ====================================
#
# Returns true if the connection is active.
def active?
# Pings the connection to check if it's still good. Note that an
# #active? method is also available, but that simply returns the
# last known state, which isn't good enough if the connection has
# gone stale since the last use.
@connection.ping
rescue OCIException
false
end
# Reconnects to the database.
def reconnect!
@connection.reset!
rescue OCIException => e
@logger.warn "#{adapter_name} automatic reconnection failed: #{e.message}"
end
# Disconnects from the database.
def disconnect!
@connection.logoff rescue nil
@connection.active = false
end
# DATABASE STATEMENTS ======================================
#
# see: abstract/database_statements.rb
def execute(sql, name = nil) #:nodoc:
log(sql, name) { @connection.exec sql }
end
# Returns the next sequence value from a sequence generator. Not generally
# called directly; used by ActiveRecord to get the next primary key value
# when inserting a new database record (see #prefetch_primary_key?).
def next_sequence_value(sequence_name)
id = 0
@connection.exec("select #{sequence_name}.nextval id from dual") { |r| id = r[0].to_i }
id
end
def insert(sql, name = nil, pk = nil, id_value = nil, sequence_name = nil) #:nodoc:
execute(sql, name)
id_value
end
def begin_db_transaction #:nodoc:
@connection.autocommit = false
end
def commit_db_transaction #:nodoc:
@connection.commit
ensure
@connection.autocommit = true
end
def rollback_db_transaction #:nodoc:
@connection.rollback
ensure
@connection.autocommit = true
end
def add_limit_offset!(sql, options) #:nodoc:
offset = options[:offset] || 0
if limit = options[:limit]
sql.replace "select * from (select raw_sql_.*, rownum raw_rnum_ from (#{sql}) raw_sql_ where rownum <= #{offset+limit}) where raw_rnum_ > #{offset}"
elsif offset > 0
sql.replace "select * from (select raw_sql_.*, rownum raw_rnum_ from (#{sql}) raw_sql_) where raw_rnum_ > #{offset}"
end
end
# Returns true for Oracle adapter (since Oracle requires primary key
# values to be pre-fetched before insert). See also #next_sequence_value.
def prefetch_primary_key?(table_name = nil)
true
end
def default_sequence_name(table, column) #:nodoc:
"#{table}_seq"
end
# SCHEMA STATEMENTS ========================================
#
# see: abstract/schema_statements.rb
def current_database #:nodoc:
select_one("select sys_context('userenv','db_name') db from dual")["db"]
end
def tables(name = nil) #:nodoc:
select_all("select lower(table_name) from user_tables").inject([]) do | tabs, t |
tabs << t.to_a.first.last
end
end
def indexes(table_name, name = nil) #:nodoc:
result = select_all(<<-SQL, name)
SELECT lower(i.index_name) as index_name, i.uniqueness, lower(c.column_name) as column_name
FROM user_indexes i, user_ind_columns c
WHERE i.table_name = '#{table_name.to_s.upcase}'
AND c.index_name = i.index_name
AND i.index_name NOT IN (SELECT uc.index_name FROM user_constraints uc WHERE uc.constraint_type = 'P')
ORDER BY i.index_name, c.column_position
SQL
current_index = nil
indexes = []
result.each do |row|
if current_index != row['index_name']
indexes << IndexDefinition.new(table_name, row['index_name'], row['uniqueness'] == "UNIQUE", [])
current_index = row['index_name']
end
indexes.last.columns << row['column_name']
end
indexes
end
def columns(table_name, name = nil) #:nodoc:
(owner, table_name) = @connection.describe(table_name)
table_cols = <<-SQL
select column_name as name, data_type as sql_type, data_default, nullable,
decode(data_type, 'NUMBER', data_precision,
'FLOAT', data_precision,
'VARCHAR2', data_length,
'CHAR', data_length,
null) as limit,
decode(data_type, 'NUMBER', data_scale, null) as scale
from all_tab_columns
where owner = '#{owner}'
and table_name = '#{table_name}'
order by column_id
SQL
select_all(table_cols, name).map do |row|
limit, scale = row['limit'], row['scale']
if limit || scale
row['sql_type'] << "(#{(limit || 38).to_i}" + ((scale = scale.to_i) > 0 ? ",#{scale})" : ")")
end
# clean up odd default spacing from Oracle
if row['data_default']
row['data_default'].sub!(/^(.*?)\s*$/, '\1')
row['data_default'].sub!(/^'(.*)'$/, '\1')
row['data_default'] = nil if row['data_default'] =~ /^(null|empty_[bc]lob\(\))$/i
end
OracleColumn.new(oracle_downcase(row['name']),
row['data_default'],
row['sql_type'],
row['nullable'] == 'Y')
end
end
def create_table(name, options = {}) #:nodoc:
super(name, options)
seq_name = options[:sequence_name] || "#{name}_seq"
execute "CREATE SEQUENCE #{seq_name} START WITH 10000" unless options[:id] == false
end
def rename_table(name, new_name) #:nodoc:
execute "RENAME #{name} TO #{new_name}"
execute "RENAME #{name}_seq TO #{new_name}_seq" rescue nil
end
def drop_table(name, options = {}) #:nodoc:
super(name)
seq_name = options[:sequence_name] || "#{name}_seq"
execute "DROP SEQUENCE #{seq_name}" rescue nil
end
def remove_index(table_name, options = {}) #:nodoc:
execute "DROP INDEX #{index_name(table_name, options)}"
end
def change_column_default(table_name, column_name, default) #:nodoc:
execute "ALTER TABLE #{table_name} MODIFY #{column_name} DEFAULT #{quote(default)}"
end
def change_column(table_name, column_name, type, options = {}) #:nodoc:
change_column_sql = "ALTER TABLE #{table_name} MODIFY #{column_name} #{type_to_sql(type, options[:limit], options[:precision], options[:scale])}"
add_column_options!(change_column_sql, options)
execute(change_column_sql)
end
def rename_column(table_name, column_name, new_column_name) #:nodoc:
execute "ALTER TABLE #{table_name} RENAME COLUMN #{column_name} to #{new_column_name}"
end
def remove_column(table_name, column_name) #:nodoc:
execute "ALTER TABLE #{table_name} DROP COLUMN #{column_name}"
end
# Find a table's primary key and sequence.
# *Note*: Only primary key is implemented - sequence will be nil.
def pk_and_sequence_for(table_name)
(owner, table_name) = @connection.describe(table_name)
pks = select_values(<<-SQL, 'Primary Key')
select cc.column_name
from all_constraints c, all_cons_columns cc
where c.owner = '#{owner}'
and c.table_name = '#{table_name}'
and c.constraint_type = 'P'
and cc.owner = c.owner
and cc.constraint_name = c.constraint_name
SQL
# only support single column keys
pks.size == 1 ? [oracle_downcase(pks.first), nil] : nil
end
def structure_dump #:nodoc:
s = select_all("select sequence_name from user_sequences").inject("") do |structure, seq|
structure << "create sequence #{seq.to_a.first.last};\n\n"
end
select_all("select table_name from user_tables").inject(s) do |structure, table|
ddl = "create table #{table.to_a.first.last} (\n "
cols = select_all(%Q{
select column_name, data_type, data_length, data_precision, data_scale, data_default, nullable
from user_tab_columns
where table_name = '#{table.to_a.first.last}'
order by column_id
}).map do |row|
col = "#{row['column_name'].downcase} #{row['data_type'].downcase}"
if row['data_type'] =='NUMBER' and !row['data_precision'].nil?
col << "(#{row['data_precision'].to_i}"
col << ",#{row['data_scale'].to_i}" if !row['data_scale'].nil?
col << ')'
elsif row['data_type'].include?('CHAR')
col << "(#{row['data_length'].to_i})"
end
col << " default #{row['data_default']}" if !row['data_default'].nil?
col << ' not null' if row['nullable'] == 'N'
col
end
ddl << cols.join(",\n ")
ddl << ");\n\n"
structure << ddl
end
end
def structure_drop #:nodoc:
s = select_all("select sequence_name from user_sequences").inject("") do |drop, seq|
drop << "drop sequence #{seq.to_a.first.last};\n\n"
end
select_all("select table_name from user_tables").inject(s) do |drop, table|
drop << "drop table #{table.to_a.first.last} cascade constraints;\n\n"
end
end
def add_column_options!(sql, options) #:nodoc:
# handle case of defaults for CLOB columns, which would otherwise get "quoted" incorrectly
if options_include_default?(options) && (column = options[:column]) && column.type == :text
sql << " DEFAULT #{quote(options.delete(:default))}"
end
super
end
# SELECT DISTINCT clause for a given set of columns and a given ORDER BY clause.
#
# Oracle requires the ORDER BY columns to be in the SELECT list for DISTINCT
# queries. However, with those columns included in the SELECT DISTINCT list, you
# won't actually get a distinct list of the column you want (presuming the column
# has duplicates with multiple values for the ordered-by columns. So we use the
# FIRST_VALUE function to get a single (first) value for each column, effectively
# making every row the same.
#
# distinct("posts.id", "posts.created_at desc")
def distinct(columns, order_by)
return "DISTINCT #{columns}" if order_by.blank?
# construct a valid DISTINCT clause, ie. one that includes the ORDER BY columns, using
# FIRST_VALUE such that the inclusion of these columns doesn't invalidate the DISTINCT
order_columns = order_by.split(',').map { |s| s.strip }.reject(&:blank?)
order_columns = order_columns.zip((0...order_columns.size).to_a).map do |c, i|
"FIRST_VALUE(#{c.split.first}) OVER (PARTITION BY #{columns} ORDER BY #{c}) AS alias_#{i}__"
end
sql = "DISTINCT #{columns}, "
sql << order_columns * ", "
end
# ORDER BY clause for the passed order option.
#
# Uses column aliases as defined by #distinct.
def add_order_by_for_association_limiting!(sql, options)
return sql if options[:order].blank?
order = options[:order].split(',').collect { |s| s.strip }.reject(&:blank?)
order.map! {|s| $1 if s =~ / (.*)/}
order = order.zip((0...order.size).to_a).map { |s,i| "alias_#{i}__ #{s}" }.join(', ')
sql << "ORDER BY #{order}"
end
private
def select(sql, name = nil)
cursor = execute(sql, name)
cols = cursor.get_col_names.map { |x| oracle_downcase(x) }
rows = []
while row = cursor.fetch
hash = Hash.new
cols.each_with_index do |col, i|
hash[col] =
case row[i]
when OCI8::LOB
name == 'Writable Large Object' ? row[i]: row[i].read
when OraDate
d = row[i]
if emulate_dates && (d.hour == 0 && d.minute == 0 && d.second == 0)
d.to_date
else
# see string_to_time; Time overflowing to DateTime, respecting the default timezone
time_array = [d.year, d.month, d.day, d.hour, d.minute, d.second]
begin
Time.send(Base.default_timezone, *time_array)
rescue
zone_offset = if Base.default_timezone == :local then DateTime.now.offset else 0 end
# Append zero calendar reform start to account for dates skipped by calendar reform
DateTime.new(*time_array[0..5] << zone_offset << 0) rescue nil
end
end
else row[i]
end unless col == 'raw_rnum_'
end
rows << hash
end
rows
ensure
cursor.close if cursor
end
# Oracle column names by default are case-insensitive, but treated as upcase;
# for neatness, we'll downcase within Rails. EXCEPT that folks CAN quote
# their column names when creating Oracle tables, which makes then case-sensitive.
# I don't know anybody who does this, but we'll handle the theoretical case of a
# camelCase column name. I imagine other dbs handle this different, since there's a
# unit test that's currently failing test_oci.
def oracle_downcase(column_name)
column_name =~ /[a-z]/ ? column_name : column_name.downcase
end
end
end
end
class OCI8 #:nodoc:
# This OCI8 patch may not longer be required with the upcoming
# release of version 0.2.
class Cursor #:nodoc:
alias :define_a_column_pre_ar :define_a_column
def define_a_column(i)
case do_ocicall(@ctx) { @parms[i - 1].attrGet(OCI_ATTR_DATA_TYPE) }
when 8 : @stmt.defineByPos(i, String, 65535) # Read LONG values
when 187 : @stmt.defineByPos(i, OraDate) # Read TIMESTAMP values
when 108
if @parms[i - 1].attrGet(OCI_ATTR_TYPE_NAME) == 'XMLTYPE'
@stmt.defineByPos(i, String, 65535)
else
raise 'unsupported datatype'
end
else define_a_column_pre_ar i
end
end
end
# missing constant from oci8 < 0.1.14
OCI_PTYPE_UNK = 0 unless defined?(OCI_PTYPE_UNK)
# Uses the describeAny OCI call to find the target owner and table_name
# indicated by +name+, parsing through synonynms as necessary. Returns
# an array of [owner, table_name].
def describe(name)
@desc ||= @@env.alloc(OCIDescribe)
@desc.attrSet(OCI_ATTR_DESC_PUBLIC, -1) if VERSION >= '0.1.14'
@desc.describeAny(@svc, name.to_s, OCI_PTYPE_UNK) rescue raise %Q{"DESC #{name}" failed; does it exist?}
info = @desc.attrGet(OCI_ATTR_PARAM)
case info.attrGet(OCI_ATTR_PTYPE)
when OCI_PTYPE_TABLE, OCI_PTYPE_VIEW
owner = info.attrGet(OCI_ATTR_OBJ_SCHEMA)
table_name = info.attrGet(OCI_ATTR_OBJ_NAME)
[owner, table_name]
when OCI_PTYPE_SYN
schema = info.attrGet(OCI_ATTR_SCHEMA_NAME)
name = info.attrGet(OCI_ATTR_NAME)
describe(schema + '.' + name)
else raise %Q{"DESC #{name}" failed; not a table or view.}
end
end
end
# The OracleConnectionFactory factors out the code necessary to connect and
# configure an Oracle/OCI connection.
class OracleConnectionFactory #:nodoc:
def new_connection(username, password, database, async, prefetch_rows, cursor_sharing)
conn = OCI8.new username, password, database
conn.exec %q{alter session set nls_date_format = 'YYYY-MM-DD HH24:MI:SS'}
conn.exec %q{alter session set nls_timestamp_format = 'YYYY-MM-DD HH24:MI:SS'} rescue nil
conn.autocommit = true
conn.non_blocking = true if async
conn.prefetch_rows = prefetch_rows
conn.exec "alter session set cursor_sharing = #{cursor_sharing}" rescue nil
conn
end
end
# The OCI8AutoRecover class enhances the OCI8 driver with auto-recover and
# reset functionality. If a call to #exec fails, and autocommit is turned on
# (ie., we're not in the middle of a longer transaction), it will
# automatically reconnect and try again. If autocommit is turned off,
# this would be dangerous (as the earlier part of the implied transaction
# may have failed silently if the connection died) -- so instead the
# connection is marked as dead, to be reconnected on it's next use.
class OCI8AutoRecover < DelegateClass(OCI8) #:nodoc:
attr_accessor :active
alias :active? :active
cattr_accessor :auto_retry
class << self
alias :auto_retry? :auto_retry
end
@@auto_retry = false
def initialize(config, factory = OracleConnectionFactory.new)
@active = true
@username, @password, @database, = config[:username], config[:password], config[:database]
@async = config[:allow_concurrency]
@prefetch_rows = config[:prefetch_rows] || 100
@cursor_sharing = config[:cursor_sharing] || 'similar'
@factory = factory
@connection = @factory.new_connection @username, @password, @database, @async, @prefetch_rows, @cursor_sharing
super @connection
end
# Checks connection, returns true if active. Note that ping actively
# checks the connection, while #active? simply returns the last
# known state.
def ping
@connection.exec("select 1 from dual") { |r| nil }
@active = true
rescue
@active = false
raise
end
# Resets connection, by logging off and creating a new connection.
def reset!
logoff rescue nil
begin
@connection = @factory.new_connection @username, @password, @database, @async, @prefetch_rows, @cursor_sharing
__setobj__ @connection
@active = true
rescue
@active = false
raise
end
end
# ORA-00028: your session has been killed
# ORA-01012: not logged on
# ORA-03113: end-of-file on communication channel
# ORA-03114: not connected to ORACLE
LOST_CONNECTION_ERROR_CODES = [ 28, 1012, 3113, 3114 ]
# Adds auto-recovery functionality.
#
# See: http://www.jiubao.org/ruby-oci8/api.en.html#label-11
def exec(sql, *bindvars, &block)
should_retry = self.class.auto_retry? && autocommit?
begin
@connection.exec(sql, *bindvars, &block)
rescue OCIException => e
raise unless LOST_CONNECTION_ERROR_CODES.include?(e.code)
@active = false
raise unless should_retry
should_retry = false
reset! rescue nil
retry
end
end
end
rescue LoadError
# OCI8 driver is unavailable.
module ActiveRecord # :nodoc:
class Base
@@oracle_error_message = "Oracle/OCI libraries could not be loaded: #{$!.to_s}"
def self.oracle_connection(config) # :nodoc:
# Set up a reasonable error message
raise LoadError, @@oracle_error_message
end
def self.oci_connection(config) # :nodoc:
# Set up a reasonable error message
raise LoadError, @@oracle_error_message
end
end
end
end
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