Assignment #3 – Advanced Ruby

Objective

For this assignment, you will be creating a query API for a CSV file of students. The API will

query a ‘YAML-base’ which you generate from the CSV file. Your API will be tested with an API

client that is provided to you.

Models

1. You are given a CSV file named s t u d e n t s . c s v

. This file contains 15000 fake student

records (along with headers) containing the following fields: G i v e n N a m e

, S u r n a m e

,

S t r e e t A d d r e s s

, C i t y

, S t a t e

, Z i p C o d e

, E m a i l A d d r e s s

, G e n d e r

, P o u n d s

2. Create a c l a s s

 called C o u r s e

 in c o u r s e . r b

 which contains c o u r s e _ n a m e

 and c o u r s e _ i d

fields which are set via the class constructor. Provide appropriate read/write accessors

to those fields.

3. Create a c l a s s

 called S t u d e n t

 in s t u d e n t . r b

 which contains the following fields (with

appropriate read/write accessors): s t u d e n t _ i d

, f i r s t _ n a m e

, l a s t _ n a m e

, c i t y

, s t a t e

,

e m a i l

, g e n d e r

, p o u n d s

, g p a

 and t a k i n g _ c o u r s e s

.

4. The S t u d e n t

 class should have an empty constructor, but should provide an ability to be

initialized via a block initializer as discussed in the lecture materials.

5. Both C o u r s e

 and S t u d e n t

 classes should override the t o _ s

 method.

Database Generator

1. Create d b _ g e n e r a t o r . r b

 file which will:

Read in the CSV file using Ruby’s CSV library (see PickAxe for an example of

reading in a * . c s v

 file with headers).

Create an array of students, where each student will have its fields populated

based on the values of the * . c s v

 file with the exception of s t u d e n t _ i d

, g p a

, and

t a k i n g _ c o u r s e s

 fields. Keep in mind that pounds is a floating point number

and should be stored appropriately.

s t u d e n t _ i d

 should just be a value which starts with 1

 and gets incremented every

time a new instance of student is created (presumably finishing ~15000)

g p a

 should be a randomly generated floating point number with the lowest value

being 2 . 0

 and the highest 4 . 0

 (Hint: take a look at Ruby’s built-in r a n d

 function)

t a k i n g _ c o u r s e s

 should be an array of 0 to 4 C o u r s e

 objects. The idea here is that

each student is taking a different number of courses. Some students might not

taking any courses while others can be taking all four.

Create 4 courses with some id and name and randomly ‘assign’ 0 to 4 courses to

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each created student. (Hint: Ruby has a wonderful s a m p l e

 method, which can

choose n

 random elements from an array.)

2. Serialize the students array to u n i v e r s i t y _ d b . y m l

 using Ruby’s YAML library (see

Pickaxe book for an example).

API

1. Create D b A p i

 class in d b _ a p i . r b

 which will serve as an API/DSL for selecting records

from the ‘YAML-base’ based on certain conditions. DO NOT re-load the YAML file

every time, rather store students loaded from the YAML file in a class variable called

s t u d e n t s

 that is retrievable from a class method called s t u d e n t s

.

2. D b A p i

 needs to have the following methods implemented:

r e q u i r e _ r e l a t i v e ‘ s t u d e n t ‘

r e q u i r e _ r e l a t i v e ‘ c o u r s e ‘

r e q u i r e ‘ y a m l ‘



c l a s s D b A p i

c l a s s

d e f s e l f . s t u d e n t s . . . e n d

d e f s e l f . s e l e c t _ b y _ g e n d e r ( g e n d e r ) . . . e n d

d e f s e l f . s e l e c t _ b y _ f i r s t _ n a m e ( f i r s t _ n a m e ) . . . e n d

d e f s e l f . s e l e c t _ b y _ l a s t _ n a m e ( l a s t _ n a m e ) . . . e n d

d e f s e l f . s e l e c t _ b y _ w e i g h t _ m o r e _ t h a n ( p o u n d s ) . . . e n d

e n d

3. The f i r s t _ n a m e

 and l a s t _ n a m e

 methods should accept a Regexp matcher as an

argument.

4. d b _ c l i e n t . r b

 (provided) will use your API. A sample output from running d b _ c l i e n t . r b

is as follows:

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The d b _ c l i e n t . r b

 prints an intersection of the number of males, the number of people whose

first name contains ‘Andr’, and the number of people who weigh more than 200 pounds.

Submission Guidelines

1. Commit all the files to you local repo and push your repo out to your private team repo

on gihub creating a remote branch called a s s i g n m e n t 3

2. You can do one of the following to accomplish the above:

Create a local branch called a s s i g n m e n t 3

 ($ g i t c h e c k o u t – b a s s i g n m e n t 3

) and

then push it out by doing $ g i t p u s h r e m o t e _ a l i a s a s s i g n m e n t 3

Work on a m a s t e r

 branch in your repo and then to $ g i t p u s h r e m o t e _ a l i a s

m a s t e r : a s s i g n m e n t 3

3. Feel free to include a README with any comments

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