Class: StudentListDBAdapter

Inherits:
Object
  • Object
show all
Defined in:
lib/source/database/student_list_db.rb

Instance Method Summary collapse

Constructor Details

#initialize ⇒ StudentListDBAdapter

Returns a new instance of StudentListDBAdapter.



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# File 'lib/source/database/student_list_db.rb', line 6

def initialize
  self.client = DBUniversity.instance
end

Instance Method Details

#add_student(student) ⇒ Object

def add_student(student) st = client.prepare_exec('insert into students (first_name, middle_name, surname, phone_number, telegram, mail, git) VALUES (?, ?, ?, ?, ?, ?, ?)') st.execute(*student_attr(student)) self.client.query('SELECT seq from sqlite_sequence where name = "students"').first.first end



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# File 'lib/source/database/student_list_db.rb', line 36

def add_student(student)
  client.prepare_exec('insert into students (first_name, middle_name, surname, phone_number, telegram, mail, git) VALUES (?, ?, ?, ?, ?, ?, ?)', *student_attr(student)).first
end

#count_student ⇒ Object 



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# File 'lib/source/database/student_list_db.rb', line 48

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

#delete_student(id_student) ⇒ Object 



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# File 'lib/source/database/student_list_db.rb', line 39

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

#get_k_n_student_short_list(k, n, data_list) ⇒ Object 



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# File 'lib/source/database/student_list_db.rb', line 52

def get_k_n_student_short_list(k,n,data_list)
  offset = (k - 1) * n
  students = client.prepare_exec('SELECT * FROM students LIMIT ?, ?', offset, n)
  puts students.to_s
  slice = students.map { |h|
    h = h.transform_keys(&:to_sym)
    StudentShort.new(Student.new(**h)) }

  puts slice
  DataListStudentShort.new(slice)
  data_list.replace_objects(slice)
  data_list
end

#into_hash(arr) ⇒ Object 



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# File 'lib/source/database/student_list_db.rb', line 10

def into_hash(arr)
  attrs = {}
  i=0
  %i[id first_name middle_name surname phone_number telegram mail git].each do |attr|
    attrs[attr] = arr[i] unless arr[i].nil?
    i=i+1
  end
  attrs
end

#replace_student(id_student, student) ⇒ Object 



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# File 'lib/source/database/student_list_db.rb', line 43

def replace_student(id_student, student)
  st ='UPDATE students SET first_name=?, middle_name=?, surname=?, phone_number=?, telegram=?, mail=?, git=? WHERE id=?'
  client.prepare_exec(st,*student_attr(student), id_student)
end

#student_by_id(id_student) ⇒ Object 



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# File 'lib/source/database/student_list_db.rb', line 20

def student_by_id(id_student)
  id_student=id_student.first.to_i
  hash = client.prepare_exec('SELECT * FROM students WHERE id = ?',id_student).first

  hash = into_hash(hash)
  return nil if hash.nil?

  Student.new(**hash)
end