Amazon MySQL Most Frequently Asked Latest Interview Questions Answers

How Do You Backup A Database In Mysql?

It is easy to backing up data with phpMyAdmin. Select the database you want to backup by clicking the database name in the left hand navigation bar. Then click the export button and make sure that all tables are highlighted that you want to backup. Then specify the option you want under export and save the output.

What Is Sqlyog?

SQLyog program is the most popular GUI tool for admin. It is the most popular MySQL manager and admin tool. It combines the features of MySQL administrator, phpMyadmin and others MySQL front ends and MySQL GUI tools.

What Is The Difference Between Char And Varchar?

A list of differences between CHAR and VARCHAR:

CHAR and VARCHAR types are different in storage and retrieval.
CHAR column length is fixed to the length that is declared while creating table. The length value ranges from 1 and 255.
When CHAR values are stored then they are right padded using spaces to specific length. Trailing spaces are removed when CHAR values are retrieved.

What Is The Difference Between Truncate And Delete In Mysql?

The DELETE command is used to delete data from a table. It only deletes the rows of data from the table while, truncate is very dangerous command and should be used carefully because it deletes every row permanently from a table.

Amazon MySQL Most Frequently Asked Latest Interview Questions Answers

How Many Triggers Are Possible In Mysql?

There are only six Triggers allowed to use in MySQL database.

Before Insert
After Insert
Before Update
After Update
Before Delete
After Delete

How to display top 50 rows?

In MySql, top 50 rows are displayed by using this following query:


SELECT * FROM
LIMIT 0,50;
1
2
SELECT * FROM
LIMIT 0,50;

How many columns can be used for creating Index?

Maximum of 16 indexed columns can be created for any standard table.

What is the different between NOW() and CURRENT_DATE()?

NOW () command is used to show current year,month,date with hours,minutes and seconds.

CURRENT_DATE() shows current year,month and date only.

What are the objects can be created using CREATE statement?

Following objects are created using CREATE statement:

DATABASE
EVENT
FUNCTION
INDEX
PROCEDURE
TABLE
TRIGGER
USER
VIEW

How many TRIGGERS are allowed in MySql table?

SIX triggers are allowed in MySql table. They are as follows:

BEFORE INSERT
AFTER INSERT
BEFORE UPDATE
AFTER UPDATE
BEFORE DELETE and
AFTER DELETE

What is the difference between mysql_fetch_array and mysql_fetch_object?

Following are the differences between mysql_fetch_array and mysql_fetch_object:

mysql_fetch_array() -Returns a result row as an associated array or a regular array from database.

mysql_fetch_object –  Returns a result row as object from database.

How can we run batch mode in mysql?

Following commands are used to run in batch mode:

mysql ;
mysql mysql.out
1
2
mysql ;
mysql mysql.out

Where MyISAM table will be stored and also give their formats of storage?

Each MyISAM table is stored on disk in three formats:

The ‘.frm’ file stores the table definition
The data file has a ‘.MYD’ (MYData) extension
The index file has a ‘.MYI’ (MYIndex) extension

What are the different tables present in MySQL?

Total 5 types of tables are present:

MyISAM
Heap
Merge
INNO DB
ISAM
MyISAM is the default storage engine as of MySQL .

What is ISAM?

ISAM  is abbreviated as Indexed Sequential Access Method.It was developed by IBM to store and retrieve data on secondary storage systems like tapes.

What is InnoDB?

lnnoDB is a transaction safe storage engine developed by Innobase Oy which is a Oracle Corporation now.

What are the nonstandard string types?

Following are Non-Standard string types:

TINYTEXT
TEXT
MEDIUMTEXT
LONGTEXT

How many TRIGGERS are allowed in MySql table?

MySql table allows following 6 triggers:

- BEFORE INSERT
- AFTER INSERT
- BEFORE UPDATE
- AFTER UPDATE
- BEFORE DELETE and
- AFTER DELETE

Differentiate between FLOAT and DOUBLE.

FLOAT stores floating point numbers with accuracy up to eight places and has four bytes while DOUBLE stores floating point numbers with accuracy upto 18 places and has eight bytes.

Tell us something about Heap tables.

- HEAP tables are found in memory.
- They are used for high speed storage on temporary basis.

Some of their characteristics are:
- They do not allow BLOB or TEXT fields.
- Only comparison operators like =, <, >, = >, =< can be used with them.
- AUTO_INCREMENT is not supported by HEAP tables
- Indexes should be NOT NULL

How do you control the max size of a HEAP table?

- Maximum size of Heap table can be controlled using MySQL config variable called max_heap_table_size.

What are the advantages of MySQL in comparison to Oracle?

- MySQL is open source software available at zero cost.

- It is portable.

- GUI with command prompt.

- Administration is supported by MySQL Query Browser.

What Is Heap Table?

Tables that are present in memory is known as HEAP tables. When you create a heap table in MySQL, you should need to specify the TYPE as HEAP. These tables are commonly known as memory tables. They are used for high speed storage on temporary basis. They do not allow BLOB or TEXT fields.

In Which Language Mysql Is Written?

MySQL is written in C and C++ and its SQL parser is written in yacc.

What Are The Technical Specification Of Mysql?

MySQL has the following technical specifications -

Flexible structure
High performance
Manageable and easy to use
Replication and high availability
Security and storage management

What Is The Difference Between Mysql And Sql?

SQL is known as standard query language. It is used to interact with the database like MySQL. MySQL is a database that stores various types of data and keeps it safe.
A PHP script is required to store and retrieve the values inside the database.

What Is The Difference Between Database And Table?

There is a major difference between a database and a table. The differences are as follows:

Tables are a way to represent the division of data in a database while, database is a collection of tables and data.
Tables are used to group the data in relation with each other and create a dataset. This dataset will be used in the database. The data which are stored in the table in any form is a part of the database, but the reverse is not true.