What do you understand by normalization in MySQL?

Vaibhav Kothia May 31, 2023 0 Comments

Normalization in MySQL is the process of organizing data into tables in such a way that the data is stored efficiently and redundancies are minimized. Normalization is an important concept in database design, as it helps to ensure data integrity and reduce data storage requirements.

For example, if a database contains information about customers and orders, the data can be normalized by creating separate tables for customers and orders. Each table would contain the relevant information about customers and orders, and the two tables could be linked together using a foreign key. This would ensure that the data is stored efficiently and redundancies are minimized.

What are the main features of Redis?

Vaibhav Kothia May 30, 2023 0 Comments

1. Data Structures: Redis supports a wide range of data structures such as strings, hashes, lists, sets, and sorted sets. For example, you can store a list of user IDs in a Redis list.

2. Atomic Operations: All operations in Redis are atomic, which means that they are performed in a single step and cannot be interrupted. This makes Redis a great choice for applications that require high performance and data integrity.

3. Persistence: Redis supports data persistence, which means that the data stored in Redis can be written to disk and recovered in case of a system failure.

4. Replication: Redis supports master-slave replication, which allows you to have a backup of your data in case of a system failure.

5. Clustering: Redis supports clustering, which allows you to shard data across multiple nodes for improved scalability and performance.

6. Lua Scripting: Redis supports Lua scripting, which allows you to write custom scripts that can be executed on the server. This is useful for performing complex operations on data stored in Redis.

7. Pub/Sub: Redis supports the publish/subscribe messaging pattern, which allows you to broadcast messages to multiple clients. This is useful for applications such as chat rooms.

What are the different commands used in Redis?

Vaibhav Kothia May 26, 2023 0 Comments

1. SET: This command is used to set a key value pair in the Redis database.

Example: SET mykey “Hello world”

2. GET: This command is used to get the value of a key from the Redis database.

Example: GET mykey

3. DEL: This command is used to delete a key from the Redis database.

Example: DEL mykey

4. EXISTS: This command is used to check if a key exists in the Redis database.

Example: EXISTS mykey

5. EXPIRE: This command is used to set a timeout for a key in the Redis database.

Example: EXPIRE mykey 60

6. KEYS: This command is used to get all the keys in the Redis database.

Example: KEYS *

What is the command to set a key in Redis?

Vaibhav Kothia May 26, 2023 0 Comments

The command to set a key in Redis is SET.

Example:

SET mykey “Hello World

What is the difference between embedded documents and linked documents in MongoDB?

Vaibhav Kothia May 26, 2023 0 Comments

Embedded documents are documents that are stored as part of another document. For example, if you have a collection of users and each user has an address, you could store the address as an embedded document within the user document.

Linked documents are documents that are stored in a separate collection. For example, if you have a collection of users and each user has an address, you could store the address in a separate collection and link it to the user document via a reference field.

What is the difference between a view and a table?

Vaibhav Kothia May 26, 2023 0 Comments

A view is a virtual table that is created from the result set of a SQL query. It does not contain any data itself, but rather references the underlying tables and columns. For example, a view can be created to show the total number of orders from a certain time period.

A table is a physical representation of data in a database. It contains the actual data that is stored in the database. For example, a table can be created to store customer information, such as name, address, and phone number.