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401/Class09/README.md

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 This topic is important to me because I want to be able to perform SQL like queries directly on collections like arrays, lists, and DB's.
 
-## [Retrospective 8](https://connerkt.github.io/Reading-Notes/401/Class09/Retro09)
+## [Retrospective 9](https://connerkt.github.io/Reading-Notes/401/Class09/Retro09)
 
 ## References
 

401/Class10/README.md

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401/Class11/README.md

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+# Introduction to Databases and ERDs
+
+This topic is important to me because I want to form databases for my application to hold data and be able to learn how to set relations.
+
+## [Retrospective 11](https://connerkt.github.io/Reading-Notes/401/Class11/Retro11)
+
+## References
+
+[Data Models](https://docs.microsoft.com/en-us/aspnet/core/data/ef-mvc/complex-data-model?view=aspnetcore-2.0)
+
+[DBMS](https://www.tutorialspoint.com/dbms/dbms_overview.htm)
+
+## Data Models
+
+- **Complex Data Model:** Developing a more intricate data model using Entity Framework Core, including multiple entities with relationships.
+
+- **Relationships:** Creating associations between entities, such as one-to-many and many-to-many relationships.
+
+- **Navigation Properties:** Defining navigation properties in entities to navigate between related data.
+
+- **DbContext:** Creating a `DbContext` class to represent the database context and manage interactions with the database.
+
+## Steps Covered
+
+1. **Creating the Model:**
+   - Defining multiple entity classes with properties representing different aspects of the data.
+
+2. **Defining Relationships:**
+   - Establishing relationships between entities using navigation properties (e.g., one-to-many, many-to-many).
+
+3. **Creating DbContext:**
+   - Creating a `DbContext` class that inherits from `DbContext` to represent the database context and manage interactions with the database.
+
+4. **Seed Data:**
+   - Adding sample data to the database context to facilitate testing and demonstration.
+
+5. **Using DbContext in a Controller:**
+   - Injecting the database context into a controller to access and manipulate data.
+
+6. **Displaying Related Data:**
+   - Utilizing navigation properties to display related data in views, enhancing the user experience.
+
+## Benefits
+
+- **Data Complexity Handling:** Learn how to manage and represent complex data scenarios in an organized and efficient manner.
+
+- **Navigation:** Understand how navigation properties simplify data retrieval and presentation, particularly when dealing with related data.
+
+- **ASP.NET Core MVC Integration:** Integrate the complex data model seamlessly into an ASP.NET Core MVC application.
+
+- **Entity Framework Core:** Gain experience using Entity Framework Core to handle database interactions and queries.
+
+## Data Models Questions
+
+1. Do some research on what a Database Schema is.
+        What is a Schema?
+        Why do we use them?
+        What do they look like?
+2. What are the different types of Database Keys?
+        What is a Primary Key?
+        What is a Foreign Key?
+        What is a Composite Key?
+        How are they different? When do you use 1 over the others?
+
+## Data Models Answers
+
+1. A schema is essentially the blueprint.
+    We use it to define how the data is going to be structured.
+    They usually are set with how the data is going to be for the end user.
+2. The colum or columns that contain values that uniquely identify each row in a    table.
+    A column used to link data between tables.
+    A combination of two or more columns in a table to uniquely identify each row.
+    Primary when you need a unique identifier.
+    Foreign when you want to establish relationships between tables
+    Composite when a single column isn't enough for uniqueness.
+
+## DBMS
+
+A **DBMS** stores data in such a way that it becomes easier to retrieve, manipulate, and produce information.
+
+A modern DBMS has the following:
+
+- Real-world Entity
+
+- Relation-based tables
+
+- Isolation of data and application
+
+- Less redundancy
+
+- Consistency
+
+- Query Language
+
+- ACID Properties
+
+- Multiuser and Concurrent Access
+
+- Multiple views
+
+- Security
+
+A typical DBMS has **users** with different rights and permissions who use it for different purposes.
+
+Some users retrieve data and some back it up.
+
+The roles can be categorized as:
+
+- Admins
+
+- Designers
+
+- End Users
+
+## DBMS Questions
+
+1. What are Relationships in a relational database?
+
+    What is a 1:1 relationship?
+    What is a Many:Many relationship?
+    How about a 1: Many or a Many:1?
+
+## DBMS Answers
+
+1. 
+
+- A connection between two tables where each record in the first table is related to exactly one record in the second table.
+- When records in one table can be associated with multiple records in another table.
+- Where records in one table can be related to multiple records in another table, but records in the second table are related to only one record in the first table.
+
+## Things I want to know more about
+
+I want to know more about setting the relationships between tables.
+
+I want to learn how to get better with understanding when I need to connect different tables.
+