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In this video, we discussed about Database design
Database Design
The organising of data using a database model is called database design. The designer decides what data must be saved and how the various data parts should be connected. They may start fitting the data to the database model using this information. The data is handled via a database management system.

While working for IBM, Edgar Frank "Ted" Codd devised the relational model for database administration, which serves as the theoretical foundation for relational databases and database management systems.

Codd's 12 rules:

After conducting a considerable study on the Relational Model of database systems, Dr. Edgar F. Codd devised his own set of twelve principles that a database must follow in order to be considered a real relational database.

These rules may be applied to any database system that merely has relational capabilities for managing stored data. This is a fundamental rule that serves as the foundation for all other rules.

information rule.(Rule 1)
A value of a table column must be stored in a database, whether it be user data or metadata. In a database, everything must be saved in a table format.

Guaranteed Access Rule. (Rule 2)
With a combination of table-name, primary-key (row value), and attribute-name, every single data piece (value) is guaranteed to be logically accessible (column value). Other methods of data access, such as pointers, are not allowed.

NULL Values Must Be Handled in a Systematic Manner (Rule 3)
A database's NULL values must be treated in a consistent and methodical manner. This is a crucial criterion since a NULL might mean one of three things: data is missing, data is unknown, or data is irrelevant.

Maintain an active online catalogue (Rule 4)
The complete database's structural description must be recorded in an online catalogue called a data dictionary, which may only be viewed by authorised users. Users can access the catalogue using the same query language they use to access the database.

Sub-Language Rule for Comprehensive Data (Rule 5)
Only a language with a linear syntax that enables data definition, data manipulation, and transaction management procedures may access a database. This language can be used either directly or through an application. It is considered a violation if the database provides access to data without using this language.

Look at the Updating Rule (Rule 6)
The system must be able to update all database views that may possibly be modified.

Insert, Update, and Delete at the Highest Level (Rule 7)
A database must be able to handle high-level insertion, update, and deletion. This can't be limited to a single row; it needs to support operations like union, intersection, and minus to produce sets of data records.

Physical Data Independence (Rule 8)
The data stored in a database must be unaffected by the applications that use it. Any changes to a database's physical structure must not have an impact on how external applications access the data.

Logical Data Independence (Rule 9)
A database's logical data must be independent of the user's perspective (application). Any changes to logical data must not have an impact on the programs that rely on it. There should be no impact or modification on the user application if two tables are combined or one is separated into two separate tables. This is one of the trickiest rules to follow.

Integrity and Independence (Rule 10)
A database must be self-contained from the application it serves. Without requiring any changes to the program, any of its integrity restrictions may be independently adjusted. This rule separates the database from the front-end program and its user interface.

Distribution Independence (Rule 11)
The end-user should not be able to tell that the data is spread across many sites. Users should always have the perception that the information is only available at one location. This rule is considered to be the bedrock of distributed database systems.

Non-Subversion Rule (Rule 12)
If a system contains a user interface that allows access to low-level records, the user interface must not be able to undermine the system or circumvent security and integrity requirements.

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