Class: Ki::Orm::Db

Inherits:
Object
  • Object
show all
Includes:
Singleton
Defined in:
lib/ki/orm.rb

Overview

This singleton class establishes the database connection and CRUD operations.

Connecting

Db.instance.establish_connection

Queries

db = Db.instance
db.find 'users', {}
db.find 'users', { name: 'Homer' }

Instance Attribute Summary collapse

Instance Method Summary collapse

Instance Attribute Details

#config ⇒ Object (readonly)

Returns the value of attribute config.



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# File 'lib/ki/orm.rb', line 21

def config
  @config
end

#connection ⇒ Object (readonly)

Returns the value of attribute connection.



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# File 'lib/ki/orm.rb', line 21

def connection
  @connection
end

#db ⇒ Object (readonly)

Returns the value of attribute db.



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# File 'lib/ki/orm.rb', line 21

def db
  @db
end

Instance Method Details

#collection_names ⇒ Object

Returns

An array of all the collection names in the database.



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# File 'lib/ki/orm.rb', line 47

def collection_names
  @db.collection_names.delete_if{|name| name =~ /^system/}
end

#count(name, hash = {}) ⇒ Object

Count the number of hashes found in a specified collection, filtered by a hash attribute

Attributes

  • name - the mongo collection name

Options

  • hash - used for filtering

Returns

The number of objects found.

Examples

db = Db.instance
db.count 'users'
db.count 'users', { name: 'Homer' }



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# File 'lib/ki/orm.rb', line 173

def count name, hash={}
  @db[name].count hash
end

#delete(name, hash) ⇒ Object

Deletes a hash from the database

Attributes

  • name - the mongo collection name

  • :hash - Filter by specific hash attributes. id required

Returns

Empty hash

Examples

db = Db.instance
db.delete 'users', { id: 'id' }
db.delete 'users', {}



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# File 'lib/ki/orm.rb', line 146

def delete name, hash
  hash = nourish_hash_id hash
  @db[name].remove hash
  {}
end

#establish_connection ⇒ Object

Creates the mongo connection.

It first checks if the env variable “MONGODB_URI” is set. The required format: docs.mongodb.org/manual/reference/connection-string/

If the env variable is not set, it will use the information stored in config.yml.



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# File 'lib/ki/orm.rb', line 31

def establish_connection
  @config = KiConfig.instance.database
  if ENV["MONGODB_URI"]
    @connection = Mongo::Connection.new
    @db = @connection.db
  else
    @connection = Mongo::Connection.new(@config['host'], @config['port'])
    @db = @connection.db(@config['name'])
  end
  self
end

#find(name, hash = {}) ⇒ Object

Find a hash in the database

Attributes

  • name - the mongo collection name

Options

  • :hash - Filter by specific hash attributes

Returns

An array of hashes which match the query criteria

Examples

db = Db.instance
db.find 'users'
db.find 'users', { id: 'id' }
db.find 'users', { name: 'Homer' }



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# File 'lib/ki/orm.rb', line 95

def find name, hash={}
  hash = nourish_hash_id hash
  @db[name].find(hash).to_a.stringify_ids
end

#insert(name, hash) ⇒ Object

Insert a hash in the database.

Attributes

  • name - the mongo collection name

  • hash - the hash which will be inserted

Returns

The inserted hash.

  • :conditions - An SQL fragment like “administrator = 1”

Examples

db = Db.instance
db.insert 'users', { name: 'Homer' }



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# File 'lib/ki/orm.rb', line 69

def insert name, hash
  @db[name].insert(hash)
  [hash].stringify_ids.first
end

#update(name, hash) ⇒ Object

Update a hash from the database

The method will update the hash obj with the id specified in the hash attribute.

Attributes

  • name - the mongo collection name

  • hash - requires at least the id of the hash which needs to be

    updated

Returns

The updated hash

Examples

db = Db.instance
db.update('users', { id: 'id', name: 'Sir Homer' })



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# File 'lib/ki/orm.rb', line 120

def update name, hash
  hash = nourish_hash_id hash
  id = hash['_id'].to_s
  hash.delete('_id')
  @db[name].update({'_id' => BSON::ObjectId(id)}, hash)
  hash['id'] = id
  hash
end