Day 92 – 100 – What is SQL and what is it used for?
SQL stands for Structured Query Language, and it is a programming language used to manage relational databases. SQL is used to create, modify, and query databases, as well as to perform various tasks such as data manipulation, data definition, and data control.
Day 93 – What is the difference between SQL and NoSQL databases?
SQL databases are relational databases that store data in tables with predefined schema, while NoSQL databases are non-relational databases that store data in flexible document formats. SQL databases are better suited for structured data that requires transactions, while NoSQL databases are better suited for unstructured data that requires scalability and flexibility.
Day 94 – What is a primary key and how is it used in SQL?
A primary key is a unique identifier for a record in a table, and it is used to enforce data integrity and facilitate data retrieval. A primary key is defined as a column or a combination of columns that uniquely identifies each row in a table.
Day 95 – What is a foreign key and how is it used in SQL?
A foreign key is a column or a combination of columns in a table that references the primary key of another table. A foreign key is used to establish relationships between tables and enforce referential integrity.
Day 96 – What is a stored procedure and how is it used in SQL?
A stored procedure is a precompiled set of SQL statements that are stored in a database and can be executed repeatedly. Stored procedures can be used to improve performance, enhance security, and simplify database management.
Day 97 – What is a trigger and how is it used in SQL?
A trigger is a database object that is executed automatically in response to certain events, such as data modification, insertion, or deletion. Triggers can be used to enforce business rules, audit data changes, and maintain data consistency.
Day 98 – What is a view and how is it used in SQL?
A view is a virtual table that is based on the result of a SQL query, and it is used to simplify complex queries and hide the underlying complexity of the database schema. Views can be used to retrieve data from multiple tables, filter and aggregate data, and enforce security policies.
Day 99 – What is a view and how is it used in SQL?
A view is a virtual table that is based on the result of a SQL query, and it is used to simplify complex queries and hide the underlying complexity of the database schema. Views can be used to retrieve data from multiple tables, filter and aggregate data, and enforce security policies.
Day 100 – What is normalization and why is it important in SQL?
Normalization is the process of organizing data in a database in a way that reduces redundancy and dependency, and ensures data consistency and integrity. Normalization is important in SQL because it helps to eliminate data inconsistencies, reduces data redundancy, and facilitates data retrieval and maintenance.