Difference Between Primary Key vs Foreign Key
As a data analyst, the primary key vs foreign key concepts should not sound Greek to you. However, if you are a beginner, you will find this tutorial useful. You see, companies are turning to databases to keep enterprise classified information. A database is a well-structured data management framework.
As the name denotes, it leverages a relational model to maintain essential information. Experts use keys to spot the connection between tableaus and data in it. This is the origin of today’s topic. In keeping with our tradition, we will start the difference between foreign key and primary key by defining the terms.
Definition of Primary Key
A primary key (main identifier or PK) helps data experts to spot each row of records in the database. The values are often peculiar as these values are never null. More often than not, it could be a single main identifier that is present in a catalog.
For instance, a company’s worker could have the following details: Employee_id, which is the PK. Well, PK could be the normal features of the data set that is exclusive to the table. This means that Employee_id is specially meant for an employee that is contained in the file.
Another good example is the social security number or account number. One cannot rule out the possibility that the system can automatically generate these special characters for representing information that is distinctive to it.
A classic example is the DBMS’ Globally Unique Identifier of MS SQL Server. It is interesting to note that one can use SQL to create one of these columns. Nevertheless, the caveat is that the content of the column must never be empty. Just before looking at the disparity, it will make perfect sense if you comprehend other term.
Definition of Foreign Key
A foreign key (FK) is used for referring to other DBMS tableaus. Experts often use it for referencing. Put simply, it contains one or more boxes that match the main identifier in the record. A better way to understand the relationship between them is that an FK is the main attribute whenever two records are put together.
Let’s say we have organizational data that contains Suppliers, Customers, Products, etc. In these categories, there are Customer_Id, Suplier_id, Product_id, etc. For the Customer, there is the name and Address_id. Supplier has name and Address_id. Lastly, the Product has Batch_id and Date_id.
Because the Product register can fit into the Supplier register, you will add the former to the latter. That is a better way to understand the FK concept. When you have joined them, the outcome is that the Product_id will now be the FK in the Customer register because there is a connection between the two records.
Main Difference Between Primary Key vs Foreign Key
Let us shed more light on the difference between primary key and foreign key below
| Basis of Comparison | Primary Key | Foreign Key |
| Definition | It is used for ensuring that data in a specific column is distinctive | It is one or more columns used in relational databases to link two tableaus |
| Function | Its function is to spot distinctive information in a tableau | It identifies the cell in a tableau that is the primary feature |
| Maximum number allowed | It allows only one main attribute | Here, this allows more than one FK attribute |
| Content | It is a mix of exclusive and non-Null content | Its content has duplicate values |
| Null Value | There is no room for it | It can contain null values |
| Deletion | The value is undeletable | Users can delete the value from the tableau |
Difference Between Primary Key and Foreign Key: Conclusion
In conclusion, we must note that this foreign key and primary key guide has discussed the most important facts that majority of people look out for. In addition, you have to know that while the former cannot be defined on global temporary tableaus, it is not the same as the latter.
Wrapping up, the foreign identifiers do not create an index unaided as the user has to do that. These are the fundamental contrasts to keep in mind whenever you think of the disparity between them.
