17 Kubernetes interview questions

A few noteworthy advantages of using MySQL are

1. High Performance - MySQL was built with a lot of focus on power/ performance
2. Flexibility - MySQL can be used on all operating systems
3. Security - Good security and storage management system
4. Query Caching - Increase the speed of the MySQL drastically
5. Replication - MySQL servers can be very easily replicated

Being a database management system MySQL expands support to numerous numeric data types; the table below contains the same.

1. TINYINT - Used for very small integers values
2. SMALLINT - Used for small integers
3. MEDIUMINT - Stores Medium-Sized integers
4. INT - Standard Integers values
5. BIGINT - Larger Integers values
6. DECIMAL - Stores fixed-point decimal values
7. FLOAT - Single precision floating values
8. DOUBLE - Double precision floating values
9. BIT - Bit field values

Binary Large Objects (BLOB) is an object that is used to store various amounts of data. There are 4 types of BLOBs and they vary based on the size of data that they can store. BLOBs are commonly used to save images in MySQL.

1. TINYBLOB
2. BLOB
3. MEDIUMBLOB
4. LONGBLOB

Views in MySQL is a method of returning a particular set of rows based on the query executed. Essentially rather than returning all the relevant records MySQL only returns the desired set of records. Furthermore, an alias can be set to columns to make the data more readable.

CREATE [OR REPLACE] VIEW view_name AS    
SELECT columns    
FROM tables    
[WHERE conditions];  

Triggers are tasks that execute when a predefined task is executed. A few examples of these tasks could include a new row being created or modified. In such cases, a particular task can be set to execute.

The various triggers allowed in MySQL are:

1. Before Insert
2. After Insert
3. Before Update
4. After Update
5. Before Delete
6. After Delete

Access Control List (ACL) is the list of permissions that an object is associated with. This list is the backbone for the security of a MySQL server.

ACLs are cached in the memory this allows it to quickly check for authentication such as user login etc.

MySQL supports three different types of relations between tables.

1. One-to-One: When one table contains a record that corresponds to exactly one other record in another table it is called a one-to-one relationship.
2. One-to-Many: When one table contains a record that corresponds to main other values in another table it is called a one-to-many relationship.
3. Many-to-Many: When a table contains many records that are linked to many other records in another table it is called a many-to-many relation. To create such a relationship, a third table containing the same key column from each of the other tables must be created.

By default MySQL contains 5 different tables they are:

1. MyISAM
2. Heap
3. Merge
4. INNO DB
5. ISAM

In order to add a new column into an existing table, we use the ALTER TABLE statement. This statement can not only be used to add a column but can also be used to delete, modify columns in an existing table

CALTER TABLE table_name     
    ADD COLUMN column_name data_type;

By default, MySQL adds a new column at the end of the table. In order to add a column in the middle of the table, the following query can be used.

ALTER TABLE table_name     
    ADD COLUMN column_name column_definition [FIRST|AFTER existing_column];

While working with tables you would face many instances where you might want to delete a table. The DROP TABLE statement can be used to achieve this.

DROP TABLE  table_name;   

Apart from this basic functionality, the DROP TABLE statement can be used to delete specific tables.

1. [TEMPORARY] - ensures that only temporary tables are deleted.
2. [IF EXISTS] - deletes a table in case it exists.

The syntax is as follows:

DROP [TEMPORARY] TABLE [IF EXISTS] table_name

While using MySQL’s workbench, data is imported using the interface. However, data can also be inserted using the following methods.

INSERT INTO table_name ( field1, field2,...fieldN )    
VALUES  ( value1, value2,...valueN );  

Once a relationship is identified the JOIN statement is used to join the tables based on the corresponding records. It essentially connects both the tables and displays them as one.

The four common ways to join two or more tables in MySQL are:

1. Inner Join
2. Left Join
3. Right Join
4. Cross Join
5. Left Join

While using the WHERE clause to filter records the LIKE operator is used to filter out records in a column that match a particular pattern. There are two wildcards used with the LIKE statement and they are

1. The percentage sign (%) - Used to represent zero, one or more characters
2. The underscore sign (_) represents a single character

Duplicate data is a common problem while working with large tables. A method to avoid displaying duplicate records the DISTINCT statement is used. This statement removes all the duplicate values.

SELECT DISTINCT something FROM tablename;

The various string types available in MySQL are:

1. SET
2. BLOB
3. CHAR
4. ENUM
5. TEXT
6. VARCHAR