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- Create correct Database Relationships
- Design databases with referential integrity
- Design primary keys and foreign keys
- Use gained skills to correct bad designs in database structures
- Decide which tables should be parents and which tables should be children
- A notepad and pencil for drawing out database designs and taking notes
The hardest part about databases is that there is a huge mountain of knowledge needed before even beginning to understand how to design and create them. It doesn't have to be this way. This course will take you from knowing nothing about databases to being able to decisively design relationships between tables. Now, if you're a beginner, you might be asking..."What are database relationships and why do they matter?" The answer is simple, every database is built off the fundamentals of database relationships.
If you want to really understand what a database is, how it works, and how to design your very first set of database tables, this course is for you.
Every lecture is taught in an easy to follow method using on-screen illustrations, drawings, and examples. This course will bring you to a level of understanding that will allow you to develop skills quickly and use them at home, in school, and even in the work setting. These are practical skills. The skills learned in this course are skills that can help you get a job in IT or Database design.
Do you want even better news? These skills are easy. No more confusion, no more fright, no more being a step behind everybody else in database technology. Here is just some of the information you will learn in this course:
- The basics of databases - what they are, how they work, and how they structure data.
- Data management - How do we keep millions of pieces of information organized and up-to-date?
- Data structure - How do we organize data so that our database is protected from anomalies?
- How to structure the three types of relationships between tables - one-to-one, one-to-many, and many-to-many. Each with practical examples.
I didn't create this course to sell you something that's going to waste your time. I created this course because I have a passion for databases and I love teaching in a fun way. This course is fun, easy to follow, and worth every penny.
- This Database Design course is for beginners who have no prior experience with databases or database design. This course will only go over designing. Avoid this course if you are more experienced or are looking to actually use SQL to program a database.
Entities are what we store Data about, Attributes are the things we store about the entity.
Every type of entity in a database will have its own table. Each attribute about that entity will have its own column.
Relations are tables. This comes from algebra, but we don't need to worry too much about that for beginning database design.
A relationship is when we have a foreign key in one table that references a primary key in another table.
Keep in mind that a relational database management system is not called relational because it has relationships, it's called relational because tables are known as relations (see previous video).
There is a difference between conceptual and physical relationship design.
When we design conceptually, we are thinking of how the entities are related in real world situations.
When we design physically, we are thinking of how we take that real world relationship and turn it into tables with primary keys and foreign keys.
A one-to-many relationship exists when an entity can be in a relationship with multiple other entities but each of the other entities can only be in a relationship with the original entity exclusively.
The example I gave was a jelous king we marries unlimited wives but each wife was to only be in a relationship with that king.
Sometimes you will have to decide the relationship.
Relationships are not always set in stone. You must decide the best way to design a database. This could either be by your own intellect or rules given to you by a boss or team leader. These rules are called business rules.
To structure many-to-many relationships we need to break the relationship up into 2 one-to-many relationships. This means that we will have a total of 3 tables, 2 parents and 1 child (the intermediary table).
Each connection between the two parents within the intermediary table will be the primary key. So they will have to be unique.