Add Freudian psychology schema demonstrating foreign key mediation pattern

README.md

@@ -13,6 +13,8 @@ This repository contains various SQL scripts, T-SQL scripts, and documentation f
 - `.Net/quick_setup.tsql`: SQL scripts for creating and managing a database named `MySchool`.
 - `ADONET/SqlInjectionPrevention.cs`: C# class for preventing SQL injection using parameterized queries.
 - `README.md`: Provides links to various resources related to SQL, ORM, and SQL linters/parsers.
+- `T-Sql/company.tsql`: Comprehensive example database schema for company management with employees, departments, projects, and complex queries.
+- `T-Sql/freudian-psychology.tsql`: Educational database schema demonstrating Freudian psychology concepts (Id, Ego, Superego) with primary and foreign key relationships.
 - `T-Sql/gg.tsql`: Script for dropping all user databases in SQL Server.
 - `T-Sql/gg2.tsql`: Script for dropping all user databases in SQL Server.
 - `T-Sql/OPENROWSET_example.tsql`: Examples of using the `OPENROWSET` function in SQL Server.
@@ -46,6 +48,23 @@ This file provides examples of using the `OPENROWSET` function in SQL Server. To
 3. Open the `OPENROWSET_example.tsql` file.
 4. Execute the script to see examples of using the `OPENROWSET` function.
 
+### T-Sql/freudian-psychology.tsql
+
+This educational schema demonstrates Freudian psychology concepts (Id, Ego, and Superego) as a practical example of database design with primary and foreign key relationships. The schema includes:
+
+- **ID_COMPONENT**: Represents primitive, instinctual drives (Life Instinct, Death Instinct)
+- **SUPEREGO_COMPONENT**: Represents moral conscience and ideals (Conscience, Ego Ideal)
+- **EGO_DECISION**: Mediates between Id and Superego components with foreign key relationships
+- **PSYCHOLOGICAL_CONFLICT**: Tracks conflicts and their resolutions
+- **DEFENSE_MECHANISM_CATALOG**: Catalogs psychological defense mechanisms
+
+To use this example:
+
+1. Open SQL Server Management Studio (SSMS).
+2. Connect to your SQL Server instance.
+3. Open the `freudian-psychology.tsql` file.
+4. Execute the script to create the psychology database and explore the sample queries demonstrating complex joins and CTEs.
+
 ## SQL Injection Prevention
 
 The `ADONET/SqlInjectionPrevention.cs` file contains a C# class for preventing SQL injection using parameterized queries. It demonstrates how to use parameterized queries to avoid SQL injection vulnerabilities. Here is an example of how to use the `SqlInjectionPrevention` class:

T-Sql/freudian-psychology-README.md

@@ -0,0 +1,98 @@
+# Freudian Psychology Database Schema
+
+## Overview
+
+This database schema demonstrates the Freudian structural model of the psyche (Id, Ego, and Superego) as an educational example of database design with primary and foreign key relationships.
+
+## Freudian Theory Background
+
+Sigmund Freud's structural model divides the psyche into three components:
+
+1. **Id**: The primitive, instinctual part of the mind containing sexual and aggressive drives. It operates on the pleasure principle, seeking immediate gratification.
+
+2. **Superego**: The moral conscience incorporating societal rules and parental values. It strives for perfection and judges our behavior.
+
+3. **Ego**: The realistic part that mediates between the desires of the id and the moral constraints of the superego. It operates on the reality principle, finding realistic ways to satisfy id's desires while considering superego's moral standards.
+
+## Database Structure
+
+### Tables
+
+1. **ID_COMPONENT**
+   - Primary Key: `idComponentId`
+   - Represents primitive drives and instincts
+   - Types: Life Instinct, Death Instinct
+
+2. **SUPEREGO_COMPONENT**
+   - Primary Key: `superegoComponentId`
+   - Represents moral rules and ideals
+   - Types: Conscience, Ego Ideal
+
+3. **EGO_DECISION**
+   - Primary Key: `egoDecisionId`
+   - Foreign Keys: `idComponentId`, `superegoComponentId`
+   - **Demonstrates the key relationship**: The Ego mediates between Id and Superego
+
+4. **PSYCHOLOGICAL_CONFLICT**
+   - Primary Key: `conflictId`
+   - Foreign Key: `egoDecisionId`
+   - Tracks conflicts between psychic components
+
+5. **DEFENSE_MECHANISM_CATALOG**
+   - Primary Key: `mechanismId`
+   - Catalogs psychological defense mechanisms by maturity level
+
+## Key Concepts Demonstrated
+
+### Primary Keys
+Each table has a unique identifier (primary key):
+- `idComponentId`, `superegoComponentId`, `egoDecisionId`, etc.
+
+### Foreign Key Relationships
+The `EGO_DECISION` table demonstrates complex relationships:
+```sql
+FOREIGN KEY (idComponentId) REFERENCES ID_COMPONENT(idComponentId)
+FOREIGN KEY (superegoComponentId) REFERENCES SUPEREGO_COMPONENT(superegoComponentId)
+```
+
+This structure mirrors the psychological theory where the ego must reference and mediate between id and superego components.
+
+## Example Queries
+
+The schema includes various query examples:
+
+1. **Basic Joins**: View ego decisions with their associated id and superego components
+2. **Conflict Analysis**: Find and analyze psychological conflicts
+3. **Defense Mechanisms**: Analyze usage patterns of different coping mechanisms
+4. **CTEs (Common Table Expressions)**: Complex queries for psychodynamic analysis
+5. **Window Functions**: Ranking and temporal pattern analysis
+
+## Educational Value
+
+This schema serves as a practical example for learning:
+- Database normalization
+- Primary and foreign key relationships
+- Complex joins across multiple tables
+- Common Table Expressions (CTEs)
+- Window functions
+- CHECK constraints for data validation
+- DEFAULT values and computed fields
+
+## Usage
+
+```sql
+-- Execute the freudian-psychology.tsql file in SQL Server Management Studio
+-- The script will:
+-- 1. Create all tables with appropriate constraints
+-- 2. Insert sample data
+-- 3. Provide example queries to explore the relationships
+```
+
+## Real-World Analogy
+
+While this example uses psychology concepts, the same pattern applies to many real-world scenarios:
+- **Order Processing**: Orders reference both Products (what) and Customers (who)
+- **Project Management**: Tasks reference both Projects (context) and Employees (who does it)
+- **Mediation Systems**: Any scenario where one entity mediates between two others
+
+The Id-Ego-Superego model provides an intuitive way to understand how foreign keys can represent complex relationships where one entity bridges or mediates between two others.