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# Implementation notes:
# 1. I had to redefine a method in ActiveRecord to make it possible to implement an autonumbering
# solution for oracle. It's implemented in a way that is intended to not break other adapters.
# 2. Default value support needs a patch to the OCI8 driver, to enable it to read LONG columns.
# The driver-author has said he will add this in a future release.
# A similar patch is needed for TIMESTAMP. This should be replaced with the 0.2 version of the
# driver, which will support TIMESTAMP properly.
# 3. Large Object support works by an after_save callback added to the ActiveRecord. This is not
# a problem - you can add other (chained) after_save callbacks.
# 4. LIMIT and OFFSET now work using a select from select from select. This pattern enables
# the middle select to limit downwards as much as possible, before the outermost select
# limits upwards. The extra rownum column is stripped from the results.
# 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.
# Copyright 2005 Graham Jenkins
require 'active_record/connection_adapters/abstract_adapter'
begin
require_library_or_gem 'oci8' unless self.class.const_defined? :OCI8
module ActiveRecord
module ConnectionAdapters #:nodoc:
class OCIColumn < Column #:nodoc:
attr_reader :sql_type
def initialize(name, default, limit, sql_type, scale)
@name, @limit, @sql_type, @scale, @sequence = name, limit, sql_type, scale
@type = simplified_type sql_type
@default = type_cast default
end
def simplified_type(field_type)
case field_type
when /char/i : :string
when /num|float|double|dec|real|int/i : @scale == 0 ? :integer : :float
when /date|time/i : @name =~ /_at$/ ? :time : :datetime
when /lob/i : :binary
end
end
def type_cast(value)
return nil if value.nil? || value =~ /^\s*null\s*$/i
case type
when :string then value
when :integer then defined?(value.to_i) ? value.to_i : (value ? 1 : 0)
when :float then value.to_f
when :datetime then cast_to_date_or_time(value)
when :time then cast_to_time(value)
else value
end
end
def cast_to_date_or_time(value)
return value if value.is_a? Date
guess_date_or_time (value.is_a? Time) ? value : cast_to_time(value)
end
def cast_to_time(value)
return value if value.is_a? Time
time_array = ParseDate.parsedate value
time_array[0] ||= 2000; time_array[1] ||= 1; time_array[2] ||= 1;
Time.send Base.default_timezone, *time_array
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 adapter for the ActiveRecord persistence framework. It relies upon the OCI8
# driver (http://rubyforge.org/projects/ruby-oci8/), which works with Oracle 8i and above.
# It was developed on Windows 2000 against an 8i database, using ActiveRecord 1.6.0 and OCI8 0.1.9.
# It has also been tested against a 9i database.
#
# 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
# * Oracle uses DATE or TIMESTAMP datatypes for both dates and times. Consequently I have had to
# resort to some hacks to get data converted 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 nasty - but if you use Duck Typing you'll probably not care very much.
# In 9i it's tempting to map DATE to Date and TIMESTAMP to Time but I don't think that is
# valid - 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 active record supports default values.
# * Referential integrity constraints are not fully supported. Under at least
# some circumstances, active record appears to delete parent and child records out of
# sequence and out of transaction scope. (Or this may just be a problem of test setup.)
#
# Options:
#
# * <tt>:username</tt> -- Defaults to root
# * <tt>:password</tt> -- Defaults to nothing
# * <tt>:host</tt> -- Defaults to localhost
class OCIAdapter < AbstractAdapter
def default_sequence_name(table, column)
"#{table}_seq"
end
def quote_string(string)
string.gsub(/'/, "''")
end
def quote(value, column = nil)
if column and column.type == :binary then %Q{empty_#{ column.sql_type }()}
else case value
when String then %Q{'#{quote_string(value)}'}
when NilClass then 'null'
when TrueClass then '1'
when FalseClass then '0'
when Numeric then value.to_s
when Date, Time then %Q{'#{value.strftime("%Y-%m-%d %H:%M:%S")}'}
else %Q{'#{quote_string(value.to_yaml)}'}
end
end
end
# 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)
name =~ /[A-Z]/ ? "\"#{name}\"" : name
end
def structure_dump
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
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 select_all(sql, name = nil)
offset = sql =~ /OFFSET (\d+)$/ ? $1.to_i : 0
sql, limit = $1, $2.to_i if sql =~ /(.*)(?: LIMIT[= ](\d+))(\s*OFFSET \d+)?$/
if limit
sql = "select * from (select raw_sql_.*, rownum raw_rnum_ from (#{sql}) raw_sql_ where rownum <= #{offset+limit}) where raw_rnum_ > #{offset}"
elsif offset > 0
sql = "select * from (select raw_sql_.*, rownum raw_rnum_ from (#{sql}) raw_sql_) where raw_rnum_ > #{offset}"
end
cursor = log(sql, name) { @connection.exec sql }
cols = cursor.get_col_names.map { |x| oci_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
(row[i].hour == 0 and row[i].minute == 0 and row[i].second == 0) ?
row[i].to_date : row[i].to_time
else row[i]
end unless col == 'raw_rnum_'
end
rows << hash
end
rows
ensure
cursor.close if cursor
end
def select_one(sql, name = nil)
result = select_all sql, name
result.size > 0 ? result.first : nil
end
def columns(table_name, name = nil)
select_all(%Q{
select column_name, data_type, data_default, data_length, data_scale
from user_catalog cat, user_synonyms syn, all_tab_columns col
where cat.table_name = '#{table_name.upcase}'
and syn.synonym_name (+)= cat.table_name
and col.owner = nvl(syn.table_owner, user)
and col.table_name = nvl(syn.table_name, cat.table_name)}
).map do |row|
OCIColumn.new(
oci_downcase(row['column_name']),
row['data_default'],
row['data_length'],
row['data_type'],
row['data_scale']
)
end
end
def insert(sql, name = nil, pk = nil, id_value = nil, sequence_name = nil)
if pk.nil? # Who called us? What does the sql look like? No idea!
execute sql, name
elsif id_value # Pre-assigned id
log(sql, name) { @connection.exec sql }
else # Assume the sql contains a bind-variable for the id
id_value = select_one("select #{sequence_name}.nextval id from dual")['id']
log(sql, name) { @connection.exec sql, id_value }
end
id_value
end
def execute(sql, name = nil)
log(sql, name) { @connection.exec sql }
end
alias :update :execute
alias :delete :execute
def begin_db_transaction()
@connection.autocommit = false
end
def commit_db_transaction()
@connection.commit
ensure
@connection.autocommit = true
end
def rollback_db_transaction()
@connection.rollback
ensure
@connection.autocommit = true
end
def adapter_name()
'OCI'
end
private
# 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 oci_downcase(column_name)
column_name =~ /[a-z]/ ? column_name : column_name.downcase
end
end
end
end
module ActiveRecord
class Base
class << self
def oci_connection(config) #:nodoc:
conn = OCI8.new config[:username], config[:password], config[:host]
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'}
conn.autocommit = true
ConnectionAdapters::OCIAdapter.new conn, logger
end
end
alias :attributes_with_quotes_pre_oci :attributes_with_quotes #:nodoc:
# Enable the id column to be bound into the sql later, by the adapter's insert method.
# This is preferable to inserting the hard-coded value here, because the insert method
# needs to know the id value explicitly.
def attributes_with_quotes(creating = true) #:nodoc:
aq = attributes_with_quotes_pre_oci creating
if connection.class == ConnectionAdapters::OCIAdapter
aq[self.class.primary_key] = ":id" if creating && aq[self.class.primary_key].nil?
end
aq
end
after_save :write_lobs
# After setting large objects to empty, select the OCI8::LOB and write back the data
def write_lobs() #:nodoc:
if connection.is_a?(ConnectionAdapters::OCIAdapter)
self.class.columns.select { |c| c.type == :binary }.each { |c|
value = self[c.name]
next if value.nil? || (value == '')
lob = connection.select_one(
"select #{ c.name} from #{ self.class.table_name } WHERE #{ self.class.primary_key} = #{quote(id)}",
'Writable Large Object'
)[c.name]
lob.write value
}
end
end
private :write_lobs
end
end
class OCI8 #:nodoc:
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
else define_a_column_pre_ar i
end
end
end
end
rescue LoadError
# OCI8 driver is unavailable.
end
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