I need to patch oracle enhanced adapter for some reasons.
In my oracle_enhanced_adapter.rb file, I need to get OCI8::Object::Mdsys::SdoGeometry.new return value, but it returns uninitialized constant OCI8::Object::Mdsys::SdoGeometry.
But, if before executing OCI8::Object::Mdsys::SdoGeometry.new command, I execute OnlineGpsPoint.first command (OnlineGpsPoint contains an sdo_geometry column) and get one of the rows in the table, OCI8::Object::Mdsys::SdoGeometry will be initialized.
The problem is that I don't want hardcoded 'OnlineGpsPoint' in my program. I just need OCI8::Object::Mdsys::SdoGeometry value.
Is there a solution for the pain?
When ruby-oci8 finds an unknown object type, it automatically defines a ruby class under OCI8::Object. If you know the object type name, it is better to define the ruby class in advance as follows:
# Oracle object type name is *guessed* from the ruby class name.
# SdoGeometry => SDO_GEOMETRY ==(public synonym)=> MDSYS.SDO_GEOMETRY
class SdoGeometry < OCI8::Object::Base
end
or
# Set Oracle object type name explicitly
class AnyClassName < OCI8::Object::Base
set_typename('MDSYS.SDO_GEOMETRY')
end
If you want same name with the automatically generated class:
module OCI8::Object::Mdsys
class SdoGeometry < OCI8::Object::Base
set_typename('MDSYS.SDO_GEOMETRY')
end
end
Related
I have a db - Postgresql v11.3 and Sequel with pg_enum, so how I can remove value from enum type?
For example, need change column enum type :
Sequel.migration do
up do
removed_values = %w["val1" "val2"]
remove_enum_value= (:old_enum_type, removed_values)
create_enum(
:enum_column,
%w[val3 val4]
)
alter_table :users do
set_column_type(
:enum_column,
'enum_column[]',
using: 'old_enum_column::text[]:::enum_column[]'
)
set_column_default :enum_column, '{}'
end
end
end
New enum type same as previous, with little different - new type doesn't have a some values. But, may be situation if somebody use missing values - migration will be crashed.
Unfortunatly, pg_enum don't have a method, that will able simple remove enum value
If you review https://www.postgresql.org/docs/12/sql-altertype.html, you will see that PostgreSQL supports adding and renaming enum values, but not removing them.
I want to add two new properties to a ruby datamapper model, one that is a date cast of a timestamp property and another that is a value from another object connected through a unique key.
So for the first case I have
property :date, DateTime
and I want to add another
property :date_date, Date
that by default will be equal to date.to_date
You should see the docs: https://datamapper.org/docs/properties.html
Specifically the sections on "Available Types" and "Setting default values".
You can do it like this:
property :date_date, Date, default: -> do |obj, prop|
obj.date.to_date
end
You can alternatively set it through a callback (https://datamapper.org/docs/callbacks.html), for example:
property :date_date, Date
before_save :set_date_date
def set_date_date
self.date_date = date.to_date
end
Note it works basically the same way in Rails' ActiveRecord as well.
I'm having trouble getting typed results out of the pg gem.
require 'pg'
require_relative 'spec/fixtures/database'
client = PG.connect( DB[:pg] )
client.type_map_for_queries = PG::BasicTypeMapForQueries.new(client)
client.type_map_for_results = PG::BasicTypeMapForResults.new(client)
client.exec( %|select * from testme;| ) do |query|
query.each {|r| puts r.inspect }
end
This program gives the output:
Warning: no type cast defined for type "money" with oid 790. Please cast this type explicitly to TEXT to be safe for future changes.
Warning: no type cast defined for type "numeric" with oid 1700. Please cast this type explicitly to TEXT to be safe for future changes.
{"string"=>"thing", "logical"=>true, "cash"=>"£1.23", "reel"=>"2.34", "day"=>#<Date: 2015-12-31 ((2457388j,0s,0n),+0s,2299161j)>, "float"=>3.45}
So: booleans and floats and dates (and integers) get converted, but not numerics or the money type.
Can anyone tell me how to "cast the type explicitly", assuming that I don't want to hard-code a solution for each table?
Hijacking this thread, as after some digging I finally found a way to add a custom decoder/encoder, so posting an example below:
require 'ipaddr'
require 'pg'
class InetDecoder < PG::SimpleDecoder
def decode(string, tuple=nil, field=nil)
IPAddr.new(string)
end
end
class InetEncoder < PG::SimpleEncoder
def encode(ip_addr)
ip_addr.to_s
end
end
# 0 if for text format, can also be 1 for binary
PG::BasicTypeRegistry.register_type(0, 'inet', InetEncoder, InetDecoder)
Here's a catch all for those seeking to cast strings by default:
client = PG.connect( DB[:pg] )
map = PG::BasicTypeMapForResults.new(conn)
map.default_type_map = PG::TypeMapAllStrings.new
client.type_map_for_results = map
Got the same problem with a text-ish field. Solved by duplicating a coder and editing its OID.
text_coder = client.type_map_for_results.coders.find { |c| c.name == 'text' }
new_coder = text_coder.dup.tap { |c| c.oid = 19 } # oid from the warning
conn.type_map_for_results.add_coder(new_coder)
How I got there: it might interest the next guy, if the problem is similar but not identical.
I read other people online talking about type_map_for_results, but how they didn't know how to define a coder. Since it was a text field in my case, I decided to try cloning an existing one. I knew I could find a textual pre-set in a Rails app, so I opened a rails console and searched:
adapter = ActiveRecord::Base.connection
connection = adapter.instance_variable_get("#connection")
mapping = connection.type_map_for_results
cd mapping # my console of choice is `pry`
ls # spotted a likely getter named `coders`
cd coders # again
ls # spotted getter `name` and setter `oid=`
So I put together the code in the solution. Gave it a try, and it worked.
It had not been straightforward to find, so I decided to exit lurker mode and share it on SO. Thereby: thanks #Andreyy for bringing me in :)
[pry cd and ls]
Google the error message: "Warning: no type cast defined for type"
You can find it's source github.
Reding the class, I would guess lines from 150 to 214 could be consiredered
examples:
register_type 0, 'text', PG::TextEncoder::String
alias_type 0, 'varchar', 'text'
Since register_type and alias_type are class methods of PG::BasicTypeRegistry::CoderMap I would play with them just and see if anything changes:
PG::BasicTypeRegistry::CoderMap.alias_type 0, 'money', 'text'
PG::BasicTypeRegistry::CoderMap.alias_type 0, 'numeric', 'text'
Reading the comments in the class it seems that the coding/decoding of those and some other fields is not implemented.
You might consider using a higher level ORM library like AvtiveRecord which implements more types (money).
I would like to better understand how Resolv::DNS handles records that are not directly supported. These records are represented by the Resolv::DNS::Resource::Generic class, but I could not find documentation about how to get the data out of this record.
Specifically, my zone will contain SSHFP and TLSA records, and I need a way to get to that data.
Through reverse engineering, I found the answer - documenting it here for others to see.
Please note that this involves undocumented features of the Resolv::DNS module, and the implementation may change over time.
Resource Records that the Resolv::DNS module does not understand are represented not through the Generic class, but rather through a subclass whose name represents the type and class of the DNS response - for instance, an SSHFP record (type 44) will be represented as Resolv::DNS::Resource::Generic::Type44_Class1
The object will contain a method "data" that gives you access to the RDATA of the record, in plain binary format.
Thus, to access an SSHFP record, here is how to get it:
def handle_sshfp(rr) do
# the RDATA is a string but contains binary data
data = rr.data.bytes
algo = data[0].to_s
fptype = data[1].to_s
fp = data[2..-1].to_s
hex = fp.map{|b| b.to_s(16).rr.rjust(2,'0') }.join(':')
puts "The SSHFP record is: #{fptype} #{algo} #{hex}"
end
Resolv::DNS.open do |dns|
all_records = dns.getresources('myfqdn.example.com', Resolv::DNS::Resource::IN::ANY ) rescue nil
all_records.each do |rr|
if rr.is_a? Resolv::DNS::Resource::Generic then
classname = rr.class.name.split('::').last
handle_sshfp(rr) if classname == "Type44_Class1"
end
end
end
I wish to have a method that takes in a string, and then updates a variable with the name of that string. This is an example of my attempt:
#other_class = OtherClass.new()
def change_variable(variable_string)
self.#other_class.send.variable_string += 1
end
I am getting the error:
syntax error, unexpected tIVAR
with the pointer just before 'send' in the method above. Does anyone have any suggestions to make this work?
You probably want instance_variable_set http://ruby-doc.org/core-2.0/Object.html#method-i-instance_variable_set
The syntax using your variables is I think:
other_var = ('#' + variable_string).to_sym
#other_class.instance_variable_set( other_var, #other_class.instance_variable_get( other_var ) + 1 )
The immediate syntatic error is that you're using self and # wrongly.
Either one is fine but not in conjunction with each other.
So in your case self.other_class.send... would be fine but then you cant declare it as #.
As would # be but then you cant do self.
These are meant to do different things and these are that
# is an instance variable and so is self but the difference is that using # calls the attribute other_class directly as to where self calls the method other_class.
So # is both a getter and setter in one so you can do
#other_class = my_milk_man as to where
self.other_class -> self.other_class (as getter),
self.other_class = my_milk_man -> self.other_class= (as setter).