MariaDB Interview Questions And Answers

Any released version.

However, MariaDB 5.2.5 and below were all compiled for 32-bit Windows only. These versions of MariaDB will run under 64-bit Windows, but they will run as 32-bit processes.

MariaDB 5.2.6 and above have 64-bit Windows binaries available. 64-bit binaries (and MSI packages) can also be built from the source, as described in Building MariaDB on Windows.

To provide a community developed, stable, and always Free DBMS that is, on the user level, broadly compatible with MySQL.

We strive for interoperability with both our own, and our upstream, communities.

Until MariaDB 5.5, MariaDB was kept up to date with the latest MySQL release from the same branch. For example MariaDB 5.1.47 was up to date with MySQL 5.1.47, and so on.

We did a merge from the main MySQL branch for every new MySQL release or when there was some critical bugfix applied to the main branch.

Since MariaDB 10.0, MariaDB includes backported features from MySQL as well as entirely new features not found anywhere else, but does not necessarily include all MySQL features.

We strive to keep our main trees as free from bugs as possible. It should be reasonably safe to pull from our trees at any time.

If you can't find help in the MariaDB documentation, in many cases the documentation for MySQL can be used. New features of MariaDB are mentioned on the MariaDB versus MySQL page and in greater detail under the MariaDB category.

If you have a question about a feature that is not properly documented or something that is not working as expected, go to the corresponding Knowledge Base page and ask your question there.

You can report and check on bugs which are unique to MariaDB in JIRA. MySQL bugs that also affect MariaDB should also be reported to MySQL.

You can also subscribe to the mailing lists and or join the IRC channel to communicate with MariaDB users and developers.

The MariaDB Corporation offers commercial support for MariaDB and all major MySQL versions (starting from MySQL 3.23).

Following is a list of features of MariaDB:

☛ MariaDB can run on different operating systems and support a wide variety of programming language.
☛ MariaDB follows a standard and popular querying language.
☛ MariaDB provides Galera cluster technology.
☛ MariaDB provides supports for PHP which is the most popular web development language.

LIMIT clause is used with SELECT statement to select a limited number of records from a table. It facilitates you to retrieve records according to your use.

Syntax:
SELECT expressions
FROM tables
[WHERE conditions]
[ORDER BY expression [ ASC | DESC ]]
LIMIT row_count;

MariaDB supports all clauses used in RDBMS. For example:

☛ MariaDB Where Clause
☛ MariaDB Like Clause
☛ MariaDB Order By Clause
☛ MariaDB DISTINCT Clause
☛ MariaDB FROM Clause
☛ Etc.

MariaDB COUNT() aggregate function is used to return the count of an expression.

Syntax:
SELECT COUNT(aggregate_expression)
FROM tables
[WHERE conditions];

MariaDB LEFT OUTER JOIN is used to return all rows from left-hand table specified in the ON condition and only those rows from the other table where the joined condition is satisfied.

LEFT OUTER JOIN is also called LEFT JOIN.

Syntax:
SELECT columns
FROM table1
LEFT [OUTER] JOIN table2
ON table1.column = table2.column;

This will show if they use tools or hack methods.
Normally, replication stops when an error occurs on the slave, so if they force an error that is replicated it would stop the all slaves at the same point in time, an "old school" method to stoping the slaves.

☛ Allow them explain and go into detail about the problem as well as the solution.
☛ Why was it a problem ?
☛ How did you fix it?
☛ Was it a revenue dependent emergency fix?
☛ Did the problem reappear or stay fixed ?

If you've got a solution that currently works with MySQL, it will work with MariaDB. Do we have specific solutions that we recommend? No. There's a wide array out there, and I'd encourage you to take your pick (the right one, for the right solution).

Development on Cassandra SE appears to have stopped.

MariaDB is a backward compatible, drop-in replacement of the MySQL® Database Server. It includes all major open source storage engines.

If you want to contribute to, or participate in the development of MariaDB, there are many ways to do so. You don't have to be a developer (but we always welcome more of those), you just have to have the willingness to help make MariaDB better. For example, we are looking for writers or translators of KB articles and people helping setting up MariaDB discussions groups.

Ready to begin?

Contributing to the MariaDB Project is the page that gathers together everything you need to get started.

The community category contains a lot of interesting links about how to participate.

You can also consider sponsoring a feature.

Welcome to the MariaDB community!

A query such as

SELECT field1, field2 FROM ( SELECT field1, field2 FROM table1 ORDER BY field2 ) alias

returns a result set that is not necessarily ordered by field2. This is not a bug.

A "table" (and subquery in the FROM clause too) is - according to the SQL standard - an unordered set of rows. Rows in a table (or in a subquery in the FROM clause) do not come in any specific order. That's why the optimizer can ignore the ORDER BY clause that you have specified. In fact, SQL standard does not even allow the ORDER BY clause to appear in this subquery (we allow it, because ORDER BY ... LIMIT ... changes the result, the set of rows, not only their order).

You need to treat the subquery in the FROM clause, as a set of rows in some unspecified and undefined order, and put the ORDER BY on the top-level SELECT.

INSERT INTO statement is used to insert records in a table in MariaDB database.

Syntax:
INSERT INTO tablename (field,field2,...) VALUES (value, value2,...);

WHERE clause is used to select or change a specific location to fetch the records from a table. It is used with SELECT, INSERT, UPDATE and DELETE statement.

Syntax:
[COMMAND] field,field2,... FROM table_name,table_name2,... WHERE [CONDITION]

MariaDB SUM function is used to return the summed value of an expression.

Syntax:
SELECT SUM(aggregate_expression)
FROM tables
[WHERE conditions];

MariaDB INNER JOIN is the most common type of join which returns all rows from multiple tables where the join condition is satisfied.

Syntax:
SELECT columns
FROM table1
INNER JOIN table2
ON table1.column = table2.column;

Allow them to talk and explain what they like and why. This will allow you to see what they hold dear as values. Some might prefer MariaDB because they are dedicated to the open source message, others might prefer Percona because if offers open source tools while others prefer MySQL because that is the source and original.

It is important to keep same defaults as MySQL. At least for now. As stated right at the top of the introduction in About MariaDB, MariaDB is an enhanced, drop-in replacement for MySQL. This means that MariaDB is designed such that you can simply replace an installation of MySQL with an installation of MariaDB without having to change anything in your application setup or config files. MariaDB offers all of the features available inside MySQL and behaves exactly the same. Plus it offers a completely free implementation of some features only available in the commercial (paid) version of MySQL Enterprise.

The issue of conflicts (like using the same port) does not arise, since for most installations only one or the other will be installed: MySQL or MariaDB. That said, for testing, comparison, and development purposes there may be a need to run both, or even multiple versions of MariaDB on the same server and it is possible to install both MariaDB and MySQL, or two versions of MariaDB, in such a way that they both coexist side by side but it is not recommended for the majority of users.

The MariaDB project is the brainchild of Michael "Monty" Widenius, the founder of MySQL®, Monty Program Ab (nowMariaDB Corporation), and a founding member of the MariaDB Foundation.

The core team consists of developers sponsored by the MariaDB Foundation, companies and individuals who are members of the Foundation, and people in the MariaDB community. MariaDB is a technocracy, and we want our core membership to reflect this.

The MariaDB Foundation's role is to be a steward of the MariaDB project. The Foundation also takes the responsibility of keeping the quality of the MariaDB project high. The MariaDB Foundation has assumed this stewardship from Monty Program Ab, which was the original driver until a foundation could be created.

A current list of active core contributors (MariaDB captains) can be found on Launchpad. Anyone with enough technical skill level who actively participates in the development of MariaDB can be part of this team. You don't have to work at the MariaDB Foundation, MariaDB Corporation, or at any other Foundation member company to be able to participate or commit code!

There is an active community around MariaDB that you can be part of. Their developer contributions can be found on the log of MariaDB contributors.

There have been some questions if MariaDB is a company or a community open source project. MariaDB is a community open source project because:

☛ It's driven by a non profit foundation.
☛ All code in MariaDB is open source. The MariaDB Foundation does not and does not intend to release any closed source modules to MariaDB. The same goes for companies which are members of the Foundation.
☛ Anyone who matches the criteria of a MariaDB captain can get commit rights to the MariaDB code base. There are many different companies and individuals among them.
☛ Anyone can contribute articles to the MariaDB Knowledge Base with very few restrictions.
☛ The MariaDB Foundation manages the MariaDB trademark, but gives broad rights to it to others.

In relational database management system, aggregate functions are the functions where the values of multiple rows are grouped together as input on certain criteria and provide a single value of more significant meaning such as a list, set etc.

Following is a list of aggregate function in MariaDB:
☛ MariaDB COUNT Function
☛ MariaDB SUM Function
☛ MariaDB MIN Function
☛ MariaDB MAX Function
☛ MariaDB AVG Function

MariaDB function is a stored program that is used to pass parameters into them and return a value.

We can easily create and drop functions in MariaDB.

There is no embedded version of MariaDB.