Class: StudentListDbAdapter

Inherits:
Object
  • Object
show all
Defined in:
lib/source/repositories/student_list_db_adapter.rb

Instance Method Summary collapse

Constructor Details

#initialize ⇒ StudentListDbAdapter

новый конструктор



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# File 'lib/source/repositories/student_list_db_adapter.rb', line 7

def initialize
  self.client = DBUniversity.instance
end

Instance Method Details

#add_student(student) ⇒ Object

добавление студента



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# File 'lib/source/repositories/student_list_db_adapter.rb', line 47

def add_student(student)
  stmt = client.prepare_exec('insert into students (first_name, last_name, paternal_name, phone, telegram, email, git) VALUES (?, ?, ?, ?, ?, ?, ?)', *student_fields(student))
end

#from_array_to_hash(arr) ⇒ Object 



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# File 'lib/source/repositories/student_list_db_adapter.rb', line 11

def from_array_to_hash(arr)
  attrs = {}
  i=0
  i[id last_name first_name paternal_name phone telegram email git].each do |attr|
    attrs[attr] = arr[i] unless arr[i].nil?
    i=i+1
  end
  attrs
end

#k_n_student_short_list(k, n, data_list = nil) ⇒ Object 



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# File 'lib/source/repositories/student_list_db_adapter.rb', line 31

def k_n_student_short_list(k,n, data_list=nil)

  offset = (k - 1) * n
  students = client.prepare_exec('SELECT * FROM students LIMIT ?, ?', offset, n)

  slice = students.map { |h|
    h = h.transform_keys(&:to_sym)
    StudentShort.new(Student.from_hash(h))
  }
  return DataListStudentShort.new(slice) if data_list.nil?

  data_list.replace_objects(slice)
  data_list
end

#remove_student(student_id) ⇒ Object

отчисление студента



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# File 'lib/source/repositories/student_list_db_adapter.rb', line 52

def remove_student(student_id)
  client.prepare_exec('DELETE FROM students WHERE id = ?', student_id)
end

#replace_student(student_id, student) ⇒ Object

обновление студента



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# File 'lib/source/repositories/student_list_db_adapter.rb', line 57

def replace_student(student_id, student)
  template = 'UPDATE students SET first_name=?, last_name=?, paternal_name=?, phone=?, telegram=?, email=?, git=? WHERE id=?'
  client.prepare_exec(template, *student_fields(student), student_id)

end

#student_by_id(student_id) ⇒ Object

вернуть студента по ид



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# File 'lib/source/repositories/student_list_db_adapter.rb', line 22

def student_by_id(student_id)
  hash = client.prepare_exec('SELECT * FROM students WHERE id = ?',student_id).first
  hash = from_array_to_hash(hash)
  return nil if hash.nil?

  Student.from_hash(hash)

end

#student_count ⇒ Object 



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# File 'lib/source/repositories/student_list_db_adapter.rb', line 63

def student_count
  client.query('SELECT COUNT(id) FROM students').next[0]
end