MariaDB Interview Questions

MariaDB is developed by MySQL developers. It is a popular public source under GNU GPL which is related to database management technology. It also provides a similar trait as MySQL.IT is the modification of MySQL. Maria DB is efficient in transferring the data into the applications. The main reason for being used MariaDB is because it is scalable, speedy and easy to hand. Moreover, it provides a lot of services like the plugin, storage and much more.

It has a lot of unique features that make it more useful and wonderful to work over it than MySQL. Some features are: -

• MariaDB is licensed under GPL, LGPL, or BSD.
• It is authorized under the BSD, LGPL, GPL MariaDB.
• It is suitable to work with the data sources like RDBMS.
• It provides a great number of storage engines.
• It provides some great extraordinary performance engines.
• It has a good paradigm inquiring language.
• It supports a lot of operating systems and can work on it.
• It supports a large number of programming language.
• It even supports the most used web development language that is PHP.
• Galera cluster technology is also supported by MariaDB.
• As it is the modification of MySQL, it supports many functions that are absent in MySQL.
• It contributes commands and many operations.
• It removes some unnecessary features present in MySQL.

The command DROP TABLE is used to delete the table in MariaDB’s database. It is needed to make sure if you really want to delete the table because it permanently deletes the table and it can’t be recovered. Triggers are also removed with the table definitions and table data so it needs to do when you are sure.

It is done by step after step. These steps are: -

• First of all, it needs to construct a database.
• When it is done, select the database.
• After that create a table by commanding CREATE TABLE statement.
• If you want to create or delete the table you must have the privilege for it

The main purpose of MariaDB is to supply a better, firm and community developed and also that is compatible with MySQL. It is always free DBMS on the basic level.

The company says that MariaDB is a modification of MySQL. MySQL is linked to the Oracle because the trademark is suggested by Oracle. Thus, the company decided to continue this trademark. As MySQL name has come from Monty's first daughter "My", so, for maintaining the continuity MariaDB has come from elder daughter Maria.

Yes, if any person is willing to participate in contributing the MariaDB they can do. They just have to fill a form that will help the person to gather around his/her team to work over projects. These projects help the MariaDB to be a better future. The projects are like writing or translations of KB essay type.

MariaDB has founded by the Michael “Monty” Widenius, the founder of MYSQL. The main focus of MariaDB foundation to keep the quality of MariaDB project high.

• The main reason for its community open source because this company is run by a non-profit organization.
• All the code in MariaDB is provided in open source. No code is closed expected to release by this foundation
• There are a lot of companies and member who meet the criteria of MariaDB. The companies and the individual who meet its criteria are also eligible to commit rights to its codebase.
• There are a few limited restrictions to those people who contribute articles otherwise everyone is free from restriction.
• It just handles the brand label and the rest of the rights are given to the others.

MariaDB Galera Cluster is also referred to as multi-master cluster of MariaDB. MariaDB Galera Cluster is accessible only on the Linux and also supports either XtraDB or InnoDB storage engines.

MariaDB Galera Cluster 10.1 is incorporated by default but in MariaDB Galera Cluster 10.0 and MariaDB Galera Cluster 5.5, it has to download individually.

Habitually the internal limits of MariaDB are enough for the size and space limits goals of storage and operating system as its InnoDB/XtraDB can reach the size up to 64 Terabytes. Although the person may have a great number of tables per databases and so many numbers of databases per server it is enough.

It does need to do anything with a new install. There are steps to follow if you want to change the size. These are:

• Firstly, go through your data and export it by moving it or by deleting the database and folders.
• When it is done, fixed innobd_page_size to any of the 4k or 8k
• After that, restart the MariaDB.
• When it is on, there appears a new XtraDB but having smaller page size.
• Now you are free to introduce your data and do what you want to do.

So, in this whole procedure, you don't need to do anything with the new installment.

There are some important tools of Gui/workbench for MariaDB Aria. These are

• Webyog/SQLyog
• HeidiSQL
• dbForge Studio for MySQL
• MySQL Workbench.

In spite of above all, the company is still trying to add some more support function.

It is also known as inner join. You can select it by the SELECT statement. JOIN is used to recover the data from tables that should be two in number or can be more than it.

There are basically two types of JOIN in MariaDB.

1. Inner join: Inner join is a type of join works only when the conditions are satisfied. It is used to recover the rows from two or more tables.
2. Outer join: It has further two types: -

• I)LEFT JOIN: In the same way of INNER JOIN, it also works on those rows in a table where the particular conditions are satisfied. LEFT OUTER JOIN is basically useful at the time of recovering those rows which have to be carried from the left-hand table but in ON condition. It is also referred as LEFT OUTER JOIN.
• 2)RIGHT JOIN: It also works on those rows in a table where the particular conditions are satisfied. RIGHT OUTER JOIN is basically useful at the time of recovering those rows which have to be carried from the right-hand table but in ON condition. It is also referred to as RIGHT OUTER JOIN.

Although there are many versions of MariaDB that can be useful to work on window 7X32 but MariaDB 5.2.5 is preferable for it.

Although 5.2.5 is also efficient for windows 7 X64. But all these versions are like to prefer 5.2.6 or latest more versions.

MariaDB function is work as a stored program in which a particular type of parameters is allowed to pass through them which in exchange, they return a value.

Procedures are also a type of class of function in the MariaDB database. It comes into use when the user needs to perform a particular task a lot of times.

MariaDB procedure also works as a stored program in which a particular type of parameters is allowed to pass through them but in exchange, they do not return any value.

There are 3 types of procedures in MariaDB database on the basis of references and parameter overwritten. These are

• IN procedure- In this type of procedure, the values of a parameter can be overwritten and referenced by the procedure.
• OUT procedure- In this type of procedure, the values of parameter can be overwritten by the procedure but it can’t be referenced by a procedure.
• IN OUT- In this type of procedure, the values of a parameter can be referenced by the procedure but it can’t be overwritten by a procedure.

Deterministic means that the result should be one value given a number of inputs parameters.

Non-deterministic means that the result can give a different value given a number of input parameters. The result can be changed because of the data, numbers, tables etc.

• TRUNCATE TABLE is used only when the whole table has to be deleted or removed permanently while the DELETE TABLE is considerably used when it has to remove only columns which can be one or more in number or has to remove the whole table.
• Both of these TABLES (TRUNCATE and DELETE) are exactly the same. The basic difference between these two is WHERE clause.
• Truncate table is quite faster than the delete table.
• DELETE TABLE is used to delete row only one at a particular time and this is recorded in the transaction log.
• TRUNCATE TABLE also kept the record in the transaction log but it firstly eliminates the data by deallocating it which is efficient to store and record. That is the main reason that TRUNCATE is faster than the DELETE TABLE.

It supports almost all types of clauses in RGDBM. For example:

• MariaDB WHERE clause: For WHERE clause there is 4 statement depending on the selection or change of location. These four statements are INSERT, DELETE, SELECT, and UPDATE.

Syntax: SELECT field1, field2 FROM table_name1, table_name2 WHERE field LIKE conditions.

• MariaDB Order by clause: In MariaDB, Order By clause is used to set the result in ascending or descending order.

Syntax: Select expressions from table_name Order By expression.

• MariaDB Distinct clause: This clause is used to delete duplicate records from the table if any.

Syntax: Select Distinct from expressions.

• MariaDB From clause: The FROM clause is used to fetch the data from the tables.

Syntax: Select columns FROM table;

The main basic functions are:

• SUM (): This function is used to summed all values in the expressions and returns the final result. In case, if there are no values in the expressions, then it returns a null value.

Syntax: Select SUM from tables where conditions.

• MIN (): It is used to find the minimum value from all of the expressions present in the table. It can also accept the string arguments and return the minimum string values.

Syntax: Select MIN from table;

• MAX (): It is opposite to MIN function. We can see it from the name that this is used to return the maximum value of an expression from the table. Same as MIN (), it also returns maximum string value if the argument is a string in form.

Syntax: Select MAX from table;

• AVG (): This function is used to find the average value of the expressions in the table. This means it retrieves the average value of an expression.

Syntax: Select AVG (aggregate expression) from table;

Yes, the user can easily create the functions in MariaDB by following the syntax.

Create FUNCTION function-name [data type]

RETURNS return-datatype |Deterministic |Not Deterministic|

{contains SQL | NO SQL data}

|SQL Security (Definer | Invoker}

|Comment ‘comment-expression’

BEGIN

Declaration section

Executable section

END;