SQL Query interview questions Insert NULL Value into primary unique key with an example #sqlserver

#sqlserver #sqlinterviewquestionsandanswers

SQL Query interview questions Insert NULL Value into primary unique key with an example

In an SQL interview, you might be asked about the consequences of inserting a NULL value into a primary unique key column. This action generally raises an error because primary keys are meant to ensure data integrity and uniqueness. A primary key constraint enforces two critical rules: uniqueness and non-null values. Therefore, inserting a NULL value violates the non-null rule and is typically disallowed. So, In Short inserting a NULL into a primary unique key often conflicts with the fundamental purpose of maintaining data integrity and uniqueness.

if you are preparing SQL interview questions in SQL Server assess a candidate's understanding of database concepts, query optimization, and data manipulation. Questions may cover topics like joins, subqueries, indexes, normalization, and transactions. Interviewees are often evaluated on their ability to write efficient SQL queries, work with relational databases, and ensure data accuracy and integrity. Please visit my previous videos and playlist of my channel.

Here is another sql interview question create composite key or primary key with multiple columns
In a SQL interview, you may encounter a question about creating a composite key or primary key with multiple columns. This involves combining two or more columns to uniquely identify records, ensuring data integrity and supporting complex relationships in a relational database schema.