SQL For Data Analysis > Understand Databases and Relationships

Difference between PK, UK and PK & FK

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The main key of the associated table is the foreign key. As a result, you can't have a primary key and a foreign key in the same column.

To ensure that data in a single column is unique, a primary key is employed. A foreign key is a column or set of columns in a relational database table that connects data from two other tables. It is used to identify a specific record in a relational database table.

The main key in the other table is referred to as the Reference Key. Foreign Key, on the other hand, is how you connect the second table to the primary tables (or Reference Key).

A composite key is a Candidate key that has many attributes. A foreign key is an attribute that is a primary key in its parent table but is not used in the host table. Non-unique and null values may be accepted by foreign keys.

A primary key is a field (or combination of fields) in a table that has values that are unique. Because each record has a separate value for the key, values of the key can be used to refer to whole records. Only one primary key per table is allowed.

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Aman Kanaujia
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All good , but provide the data also for the assignment , Without data the interest is less day by day from the course. So, try to solve this problem as asap.

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Snehil
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Everything is good but keyboard sounds more harsh and overlap your voice whereas this course is best.

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FAROOK MOHAMMAD
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Hello sir, explaination is excellent. I have a request please send the db in excel or SQL file.

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Hari Prakash
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In SQL Join Function's 2nd video - Teacher's voice dose not match with background content that are plays

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Aakash Mavar
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Excellent

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Pravin Kashid
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  2. SQL Commands
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  3. What is DBMS
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  4. What is RDBMS
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  1. Database Relationships
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  2. Primary Key
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  3. Unique Key
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  4. Foreign Key
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  5. Difference between PK, UK and PK & FK
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  1. SQL Server Installation Step by Step
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  1. How to Create Database in SQL Server
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  2. Assignment : SQL Create Table
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  1. Filtering Data using Selection Command
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  7. SQL Functions for Data Analytics - 1
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  12. How to use SQL Conditional Statements
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  13. How to use SQL Group by Clause
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  14. SQL Practical with Examples
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  15. Assignment : SQL Date and Time
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  1. Type of Joins in SQL - INNER, LEFT
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  5. SQL Joins Practical Session 3
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  6. SQL Joins Practical Session 4
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  7. SQL Joins Practical Session 5
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  6. Adding Multiple Records with Insert Statement
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  8. Insertion from Multiple Tables
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  1. Loading & Connecting Different Files in SQL
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  1. Course Summary
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  1. Interview Questions Part 1
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