MariaDB Interview Questions and Answers

Last update: 21 Mar 2022, 39 Questions

MariaDB is the most popular database created by MySQL's original developers. It carries an intention to replace MYSQL as of concern of MYSQL acquisition by Oracle. MariaDB contains open source and relational database technology. As being a rational database, it provides you with the strength of storing data in various tables. Our extensive collection of MariaDB interview questions is guaranteed to help you get your dream job. Read on!


  • MariaDB incorporates a wide choice of storage engines, including high-performance storage engines, for working with different RDBMS information sources.
  • MariaDB utilizes a standard query language.
  • MariaDB keeps running on various operating systems with a wide range of programming language..
  • MariaDB supports PHP, that widely used for development.
  • MariaDB gives Galera cluster technology support that is a synchronous multi-master database.
  • MariaDB additionally offers numerous tasks and directions inaccessible in MySQL and dispenses with/replaces highlights affecting execution contrarily.

Looking for a new job? Do not miss to read our MariaDB interview questions and answers.

Most Frequently Asked MariaDB Interview Questions

Here in this article, we will be listing frequently asked MariaDB Interview Questions and Answers with the belief that they will be helpful for you to gain higher marks. Also, to let you know that this article has been written under the guidance of industry professionals and covered all the current competencies.

1. How to create a databse?

MariaDB needs to apply PHP mysql_query function to create a database.
Basic syntax − bool mysql_query( sql, connection );

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2. What are the basic requirements to create or delete database into MariaDB?

We need privileges To create or delete any database in MariaDB to root users or admins. Under this process, you have two choices for making a database − the mysqladmin binary and a PHP script.

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3. What are those two parameters that help to drop the database?

1)SQL : This required parameter comprises of the SQL query expected to play out the operation.
2)Connection : At the point when a parameter is not determined, this optional parameter calls the most recent connection.

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4. How many kinds of data types it has?

There are three kinds of data type-

  • Numeric Data Types
  • Date and Time Data Types
  • String DataTypes
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5. Why do we need to select the database and how?

Selecting a database is the necessary part as many databases exist there.
We have two options to select database first using a command prompt or through a PHP script.

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6. How many queries are present in MariaDB?

There are six queries

  • Creating Table : In a table creation, determine its name, field names, and field definition.
  • Drop Table : In this process, we delete a table these deleted tables are irrecoverable.
  • Insert Table : Embeddings information into a table requires the INSERT query.
  • Select Table : Select query applies on selected rows to retrieve them. It also gives different alternatives to specify the table use.
  • Update Table : update query let you modify the existing data of the table by changing values.
  • Delete Table : The delete query erases table row from the predefined table and returns the erased quantity.
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7. What is WHERE clauses also share qualities ?

WHERE clauses sieve various queries like SELECT, UPDATE, DELETE, and INSERT. They represent criteria used to determine activity. They are visible after a table name, and their condition follows. The WHERE clause equally crucial like statements.

Qualities of the WHERE clause –

  • It is an alternative.
  • It enables any condition to be specified.
  • It provides the specification of various conditions.
  • It's a Case sensitivity only applies to statements using LIKE comparisons.
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8. What is LIKE clauses also share qualities ?

The LIKE clause includes a wide range of matching patterns, In this situation where it needs multiple results with shared characteristics. The patterns used for matches numbers of characters (0 or more) is percentile (%) and hyphen (-) as a single character.

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9. What order by clause does?

It helps to sort the results of queries. It specifies the data in an operating order along with data sorting options in ascending (ASC) or descending (DESC) order. By default, it provides ascending order on the mission of order placements. ORDER BY clauses contains a wide range of statements such as DELETE and UPDATE. ORDER BY clauses works on final result of a table that is why they come at the end of a statement instead of in a subquery or earlier function set.

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10. Give a brief detail about JOIN. JOIN query merge two or more tables into a single one. It gathers data from various tables. This is a collection of following statements such as SELECT, UPDATE and DELETE. The old syntax of JOINS used to work on implicit joins without any keywords. Now it has the keyword to work best for readability, maintenance, and best practices. JOINs has a various form of the different type of aggregation depends upon their specifications such as such as a left join, right join, or inner join.
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11. What is the meaning of NULL?

When we use a NULL value, it means they are unknown values. We can not consider them as empty strings or zero, which are valid values. In table creation, section details take into consideration setting them to acknowledge null values, or reject them. Essentially use a NULL or NOT NULL statement. This has applications in instances of missing record data like an ID number. Client characterized factors have an estimation of NULL until express task. Put away routine parameters and neighborhood factors permit setting an estimation of NULL. At the point when a neighborhood variable has no default esteem, it has an estimation of NULL.

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12. What are the variations of Null Operators?

There are certain operators cannot use with Null operator as result will be null also. Standard comparison operators cannot compare null values because it will return only null, not true or false.

Other available forms of operators are −

  • IS NULL − It gives you result after testing for a NULL value.
  • IS NOT NULL − It gives you confirmation about the unavailability of a NULL value.
  • ISNULL − If it discovery a NULL value it returns a value of 1 if it is absent it returns a value of 0.
  • COALESCE − In case of absence it returns a NULL value but generally, returns the first non-NULL value of a list.
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13. Expain variations of JOIN?

As we know, JOIN retrieves data from the various table.

There are three forms of JOIN-

1) INNER JOIN : is the most common method of JOIN in which user get row from multiple tables when join condition is satisfied.

2) LEFT OUTER JOIN : This method returns all row from the left-hand table when ON condition is satisfied.

3) RIGHT OUTER JOIN : This method returns all row from the left-hand table when ON condition is satisfied.

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14. What is the use of regular expression?

A regular expression used to match string on a given pattern. String match pattern use for search option.

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15. What is a transaction in MariaDB?

A transaction is a sequence of various operations. They work individually but terminates only when each operation executes successfully. Which mean once all operations have been completed only then the transaction will be successful. In case of a single operation gets fail it impacts the entire transaction as each sequence depends up to another one.

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16. What is the structure of a Transaction?

The general structure of an exchange explanation comprises of starting with START TRANSACTION. The subsequent stage is embeddings at least one or more commands/operations, inserting statements that check for mistakes, inserting ROLLBACK statements to deal with any error found, at last, inserting a COMMIT statement to implement modification on a successful operation.

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17. Explain ACID in Transaction.
  • Atomicity − It interrupts the failures and rolls back the modification because It is responsible accomplish all operations.
  • Consistency − It is responsible for changes implement by the database on a successful transaction.
  • Isolation − It prepares the transaction operations to perform individually in a transaction.
  • Durability − It is responsible for the persistence of a successful transaction in case an event of system failure occurs.
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18. What is Alter Command?

Alter command innovate the structure of an existing table, which allows modification such as add and remove of columns, modification of indices, modification in data types and modification in names. At the point metadata lock is active, Alter command is ready to apply modifications.

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19. What is an index?

Indexes are tools to retrieve records by acceleration. An index column gets an entry for each value by an index production. Indexes are a companion with the various column, assist quick exploration and sufficient record management. Creating an index is consider which columns are frequently using in your query.

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20. What is Table statistics?

MariaDB uses indexes intensely to optimize queries given quick access to data and gave statistics. There are some users found indexes are complicated to manage. MariaDB provides a self-sufficient storage engine along with the availability of statistics table. Statistics are calculated by storage engine for every table in every storage engine. storage engine even calculates the statistics for columns that are not indexed.

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21. Explain Temporary tables?

There are some beneficial operations in temporary tables because of speed and disposable data. You can terminate the life of a temporary table by ending of a session, employment through command prompt, using a PHP script or through a client program. It is not typically visible in a system.

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22. What are the backup loading methods?

There are three methods-

  • LOAD DATA statement
  • MYSQLDUMP restore.
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23. What is the instruction you will give for special characters and quotes?

Quotes and special characters are not readable by an interpreter in a LOAD DATA statement. The statement only understands the simple values without quotes and backslashes as escape characters. The statement prefers field clause to specify formatting.

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24. How many Aggregate Functions are present in MariaDB?

There are 5 functions:

  • COUNT: It checks the quantity of records.
  • MIN: It uncovers the base estimation of a lot of records.
  • AVG: It computes the normal estimation of a lot of records.
  • SUM: It figures the entirety of a lot of records.
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25. How SQL Injection Protection works?

The simple act of tolerating client input opens the way to exploits. Initially, the logical management of data creates a problem which fortunately has a way to get rid of his flaw.
When a user inserts any data like name or code logic, an error occurs to rescue that error we need to use SQL injection. The code offers access to the MariaDB which will perform on the database. Continuously consider information entered by clients, suspect and need solid approval before any preparing. Play out this approval through pattern coordinating.

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