= ERModel v01

== Diagram

== Entities

{{{User}}}

This is the core entity that represents every person registered on [https://develop.finki.ukim.mk/projects/petsitter/#PetSitter PetSitter]. It acts as a supertype for {{{Admin}}}/{{{PetOwner}}}/{{{PetSitter}}} so we can store the common attributes only in {{{User}}}.

'''Candidate keys:'''
* {{{user_id}}} - '''Primary key'''; numeric id, most efficient for indexing
* {{{username}}} - unique but not as efficient as {{{user_id}}}
* {{{email}}} - unique but not as efficient as {{{user_id}}}

'''Attributes:'''

* {{{user_id}}} - Numeric (Required, Unique, Auto-generated integer).

* {{{username}}} - Text (Required, Unique, 4-20 characters).

* {{{first_name}}} - Text (Required).

* {{{last_name}}} - Text (Required).

* {{{password}}} - Text (Required, Hashed format, Min. 8 characters).

* {{{email}}} - Text (Required, Unique, Standard email format).

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{{{Admin}}}

Subtype/specialization of {{{User}}} entity. Inherits from {{{User}}}. Has administrator privileges.

'''Candidate keys:'''
* {{{user_id}}} - Inherits {{{user_id}}} from {{{User}}}

'''Attributes:'''

* Inherits all attributes from {{{User}}}

---- 

{{{PetOwner}}}

Subtype/specialization of {{{User}}} entity. Inherits from {{{User}}}. Is able to make bookings for their {{{Pet}}} and request a {{{PetSitter}}}.

'''Candidate keys:'''
* {{{user_id}}} - Inherits {{{user_id}}} from {{{User}}}

'''Attributes:'''

* Inherits all attributes from {{{User}}}

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{{{PetSitter}}}

Subtype/specialization of {{{User}}} entity. Inherits from {{{User}}}. Provides services to {{{PetOwner}}}. Is able to confirm or deny bookings.

'''Candidate keys:'''
* {{{user_id}}} - Inherits {{{user_id}}} from {{{User}}}

'''Attributes:'''

* Inherits all attributes from {{{User}}}

---- 

{{{Pet}}}

The animal that will be taken care of. Track the identity, special needs, age of the pet in the booking. Linked to {{{PetType}}} to categorize animals more efficiently.

'''Candidate keys:'''
* {{{pet_id}}} - '''Primary key'''; Unique surrogate key.

'''Attributes:'''

* {{{pet_id}}} - Numeric (Required, Unique, Auto-generated integer).

* {{{name}}} - Text (Required).

* {{{photo}}} - Text/URL (Optional, URL format).

* {{{age}}} - Numeric (Required, non-negative integer).

* {{{password}}} - Text (Required, Hashed format, Min. 8 characters).

* {{{special_needs}}} - Text (Optional).

* {{{description}}} - Text (Optional).

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{{{PetType}}}

Entity used to categorize pets (for example Cat, Dog, Rabbit, Bird). Used for storing attributes that would repeat a lot of times in one single {{{Pet}}} entity.

'''Candidate keys:'''
* {{{pet_id}}} - '''Primary key'''; Unique surrogate key.
* {{{species}}} - Unique but not as efficient as a numeric id key.

'''Attributes:'''

* {{{pettype_id}}} - Numeric (Required, Unique, Auto-generated integer).

* {{{species}}} - Text (Required, Unique).

* {{{average_lifespan}}} - Numeric (Optional).

* {{{needs_outdoor_walk}}} - Boolean (Required, 0 or 1).


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{{{Booking}}}

The entity that connects {{{PetOwner}}}, {{{PetSitter}}}, {{{Pet}}} and the services requested for the {{{Pet}}}

'''Candidate keys:'''
* {{{booking_id}}} - '''Primary key'''; Unique surrogate key.

'''Attributes:'''

* {{{booking_id}}} - Numeric (Required, Unique, Auto-generated integer).

* {{{status}}} - Text (Required, for example 'Pending', 'Confirmed', 'Completed', 'Rejected').

* {{{date_from}}} - Date (Required).

* {{{date_to}}} - Date (Required).

* {{{address}}} - Text (Required, location of the service).