Recommended Schema: Person Column Type Notes Person_ID Primary Key Unique identifier for each person Name String Name of the person Company_ID Foreign Key References Company.Company_ID Phone String Phone number Email String Email address Company
Column Type Notes Company_ID Primary Key Unique identifier for each company Name String Name of the company Address String Address of the company City String City of the company State String State of the company Invoice_ID Foreign Key Unique Reference to Invoice.Invoice_ID (1-to-1 relationship) Invoice
Column Type Notes Invoice_ID Primary Key Unique identifier for each invoice Summary_ID Foreign Key References Summary_Section.Summary_ID Detailed_ID Foreign Key References Detailed_Section.Detailed_ID Summary_Section
Column Type Notes Summary_ID Primary Key Unique identifier for the summary InvoiceNumber String Invoice number Date Date Invoice date DueDate Date Invoice due date Detailed_Section
Column Type Notes Detailed_ID Primary Key Unique identifier for the detailed section Person_ID Foreign Key References Person.Person_ID Amount Decimal Amount related to the person Info String Additional information InvoiceNumber String Invoice number Date Date Invoice date DueDate Date Invoice due date

Key Adjustments:

1. Foreign Key Relationships o Ensure that Company.Invoice_ID has a unique constraint to enforce a 1-to-1 relationship between Company and Invoice. o Both Summary_Section and Detailed_Section must maintain foreign keys (Summary_ID and Detailed_ID) that point back to their respective invoices in the Invoice table.
2. Invoice Sections o Instead of having Summary_Section and Detailed_Section separated, you might consider combining them into one Invoice table if the data is tightly coupled. However, if these sections must remain separate for logical or reporting reasons, your design is valid.
3. Person and Detailed_Section o The Person_ID field in Detailed_Section implies that multiple entries in Detailed_Section can reference the same person. This is fine if people can appear on multiple invoices or invoice details.
4. Indexing o Index all foreign keys to improve query performance. o Add composite indexes for fields that are commonly queried together (e.g., Company_ID and Person_ID).
5. Naming Convention o Use consistent and descriptive column names (e.g., FK_Company_Invoice for foreign keys) to make the schema easier to understand.

Relationship Diagram Here’s how the relationships look conceptually: • Company (1-to-1) → Invoice • Invoice (1-to-1) → Summary_Section • Invoice (1-to-many) → Detailed_Section • Company (1-to-many) → Person • Person (1-to-many) → Detailed_Section

SQL Example Here’s an example of creating tables with these relationships: sql CopyEdit CREATE TABLE Company ( Company_ID INT PRIMARY KEY, Name NVARCHAR(100), Address NVARCHAR(255), City NVARCHAR(100), State NVARCHAR(50), Invoice_ID INT UNIQUE, FOREIGN KEY (Invoice_ID) REFERENCES Invoice(Invoice_ID) );

CREATE TABLE Person ( Person_ID INT PRIMARY KEY, Name NVARCHAR(100), Company_ID INT, Phone NVARCHAR(15), Email NVARCHAR(100), FOREIGN KEY (Company_ID) REFERENCES Company(Company_ID) );

CREATE TABLE Invoice ( Invoice_ID INT PRIMARY KEY, Summary_ID INT UNIQUE, Detailed_ID INT UNIQUE, FOREIGN KEY (Summary_ID) REFERENCES Summary_Section(Summary_ID), FOREIGN KEY (Detailed_ID) REFERENCES Detailed_Section(Detailed_ID) );

CREATE TABLE Summary_Section ( Summary_ID INT PRIMARY KEY, InvoiceNumber NVARCHAR(50), Date DATE, DueDate DATE );

CREATE TABLE Detailed_Section ( Detailed_ID INT PRIMARY KEY, Person_ID INT, Amount DECIMAL(10, 2), Info NVARCHAR(255), FOREIGN KEY (Person_ID) REFERENCES Person(Person_ID) );

Next Steps:

1. Test the schema with sample data to ensure it behaves as expected.
2. Use appropriate indexing and constraints to enforce relationships.
3. Ensure your queries (e.g., JOINs) retrieve the correct results for reports or summaries.