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Data_Definitions_and_Normalization.md

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Data Definitions and Normalization

Data Definitions

Detailed data definitions for all entities are listed below.

EMPLOYEE

Attribute Data Type Constraints Description
EmployeeID INT PRIMARY KEY Unique identifier for each employee.
FirstName VARCHAR(255) NOT NULL Employee's first name.
MiddleInitial CHAR(1) Employee's middle initial.
LastName VARCHAR(255) NOT NULL Employee's last name.
Title VARCHAR(255) Professional title of the employee (Mr., Ms.)
CorporateEmail VARCHAR(50) NOT NULL Employee's corporate email address.
CorporatePhone VARCHAR(20) Employee's corporate phone number.
PersonalPhone VARCHAR(20) Employee's personal phone number.
DepartmentID INT FOREIGN KEY ID linking to the employee's department.

DEPARTMENT

Attribute Data Type Constraints Description
DepartmentID INT PRIMARY KEY Unique identifier for each department.
Name VARCHAR(255) NOT NULL Name of the department.
MailboxNumber INT Mailbox number assigned to the department.
PhoneNumber VARCHAR(20) Contact phone number for the department.

DEVICE

Attribute Data Type Constraints Description
DeviceID INT PRIMARY KEY Unique identifier for each device.
Brand VARCHAR(255) NOT NULL Brand of the device.
Model VARCHAR(255) NOT NULL Model of the device.
Value DECIMAL(10,2) Monetary value of the device in euros.
RegistrationDate DATE NOT NULL Date when the device was registered.
DisposalDate DATE Date when the device was disposed of.
EmployeeID INT FOREIGN KEY ID of the employee to whom the device is assigned.

LOCATION

Attribute Data Type Constraints Description
LocationID INT PRIMARY KEY Unique identifier for a location.
BuildingName VARCHAR(255) Name of the building.
OfficeNumber VARCHAR(50) Number of the office.

DESKTOP

Attribute Data Type Constraints Description
DeviceID INT PRIMARY KEY, FOREIGN KEY Unique identifier for a desktop device, references DEVICE.
StaticIP VARCHAR(15) Static IP address of the desktop.
LocationID INT FOREIGN KEY Location of the desktop, references LOCATION.

MOBILE_DEVICE

Attribute Data Type Constraints Description
DeviceID INT PRIMARY KEY, FOREIGN KEY Unique identifier for a mobile device, references DEVICE.
ScreenLockEnabled BOOLEAN Indicates if the screen lock is enabled.
IsEncrypted BOOLEAN Indicates if the device is encrypted.

ASSET_REGISTER

Attribute Data Type Constraints Description
AssetID INT PRIMARY KEY Unique identifier for an asset.
DeviceID INT FOREIGN KEY Associated device ID, references DEVICE.
AcquisitionDate DATE Date when the asset was acquired.
DisposalDate DATE Date when the asset was disposed of.

DEVICE_TYPE

Attribute Data Type Constraints Description
DeviceTypeID INT PRIMARY KEY Unique identifier for a device type.
TypeName VARCHAR(255) NOT NULL Name of the device type.

SERVICE

Attribute Data Type Constraints Description
ServiceID INT PRIMARY KEY Unique identifier for a service.
Name VARCHAR(255) NOT NULL Name of the service.
Description TEXT Description of the service.

SERVICE_ACCESS

Attribute Data Type Constraints Description
ServiceID INT PRIMARY KEY, FOREIGN KEY ID of the service, references SERVICE.
EmployeeID INT PRIMARY KEY, FOREIGN KEY ID of the employee, references EMPLOYEE.
AccessApprovalDate DATE Date when access was approved for the employee.

PROJECT_MEMBERSHIP

Attribute Data Type Constraints Description
ProjectID INT PRIMARY KEY, FOREIGN KEY Identifier for the project, references PROJECT.
EmployeeID INT PRIMARY KEY, FOREIGN KEY Identifier for the employee, references EMPLOYEE.
RoleID INT FOREIGN KEY Identifier for the role, references the ROLE table.

PROJECT

Attribute Data Type Constraints Description
ProjectID INT PRIMARY KEY Unique identifier for a project.
Name VARCHAR(255) NOT NULL Name of the project.
Description TEXT Description of the project.
StartDate DATE Start date of the project.
EndDate DATE End date of the project.

ROLE

Attribute Data Type Constraints Description
RoleID INT PRIMARY KEY Unique identifier for a role.
Description TEXT Description of the role.

OPERATING_SYSTEM

Attribute Data Type Constraints Description
OSID INT PRIMARY KEY Unique identifier for an operating system.
OperatingSystem VARCHAR(255) NOT NULL Name of the operating system.
OperatingSystemVersion VARCHAR(60) Version of the operating system.

DEVICE_HISTORY

Attribute Data Type Constraints Description
HistoryID INT PRIMARY KEY Unique identifier for a device history record.
DeviceID INT FOREIGN KEY ID of the device, references DEVICE.
PreviousDeviceTypeID INT FOREIGN KEY Previous type of the device, references DEVICE_TYPE.
PreviousOSID INT FOREIGN KEY Previous operating system of the device, references OPERATING_SYSTEM.
ChangeDate DATE Date when the change was recorded.
ChangedBy INT FOREIGN KEY ID of the employee who recorded the change, references EMPLOYEE.

DEVICE_APPROVAL

Attribute Data Type Constraints Description
ApprovalID INT PRIMARY KEY Unique identifier for a device approval record.
DeviceID INT FOREIGN KEY ID of the device, references DEVICE.
ApprovalStatusID INT FOREIGN KEY Status of the approval, references APPROVAL_STATUS_CODE.
ApprovalDate DATE Date when the device was approved.

APPROVAL_STATUS_CODE

Attribute Data Type Constraints Description
ApprovalStatusID INT PRIMARY KEY Unique identifier for an approval status.
StatusCode INT Numeric code for the status.
StatusDescription VARCHAR(50) Description of the status.

DEVICE_ACTIVATION

Attribute Data Type Constraints Description
ActivationID INT PRIMARY KEY Unique identifier for a device activation.
DeviceID INT FOREIGN KEY Identifier for the device, references DEVICE.
ActivationDate DATE NOT NULL Date when the device was activated.
ActivatedBy INT FOREIGN KEY Identifier for the IT staff who activated the device, references IT_STAFF.

IT_STAFF

Attribute Data Type Constraints Description
StaffID INT PRIMARY KEY Unique identifier for an IT staff.
FirstName VARCHAR(255) NOT NULL First name of the IT staff.
LastName VARCHAR(255) NOT NULL Last name of the IT staff.
Email VARCHAR(255) NOT NULL Email address of the IT staff.

GROUP_POLICY

Attribute Data Type Constraints Description
PolicyID INT PRIMARY KEY Unique identifier for a group policy.
DepartmentID INT FOREIGN KEY Identifier for the department, references DEPARTMENT.
PolicyName VARCHAR(255) NOT NULL Name of the group policy.
PolicyDetails TEXT Details of the group policy.

Normalization

First Normal Form (1NF)

An entity is in 1NF if it meets the following criteria:

  • Contains only atomic individual values, meaning each column is indivisible.
  • Each column has a unique name.
  • The values in each column are of the same data type.
  • Each row is unique.

Second Normal Form (2NF)

An entity is in 2NF if:

  • It is already in 1NF, and
  • All non-key attributes are fully functionally dependent on the primary key.

Third Normal Form (3NF)

An entity is in 3NF if:

  • It is already in 2NF, and
  • There are no transitive relationships between non-key attributes.

Examples Demonstrating Normalization

First Normal Form (1NF)

In the EMPLOYEE entity, each field contains only atomic values:

  • EmployeeID
  • FirstName
  • MiddleInitial
  • LastName
  • Title
  • CorporateEmail
  • CorporatePhone
  • PersonalPhone
  • DepartmentID

Second Normal Form (2NF)

The SERVICE_ACCESS entity has a composite primary key (ServiceID, EmployeeID). The AccessApprovalDate is fully dependent on the entire composite key.

Third Normal Form (3NF)

In the DEVICE entity, all attributes are directly dependent on the primary key DeviceID:

  • Brand
  • Model
  • Value
  • RegistrationDate
  • DisposalDate
  • EmployeeID

All entities in the ERD comply with 3NF, ensuring that the design is free of redundancy and ensures data integrity.