MySQL Interview Questions

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1) What is MySQL?

MySql is defined as multi-user DBMS which is built and distributed my MySQLab now acquired by Oracle Co.

2) Enlist the features of MySQL.

  • Cross-Platform Support
  • Wide range of Interface for Application Programming
  • Pre-defined Procedure e.g. Triggers and Cursors.

3) What is the default port of MySQL.

Default Port: 3306.

4) Give some MySQL Function.

5) What are the different tables present in MySQL?

  • MyISAM
  • Heap
  • Merge
  • INNO DB
  • ISAM

6) Differentiate between SQL and MySQL.

SQL is a Standard Query Language which is designed to access the database like MySQL, Oracle DBA. MySQL is a database which stores data in a defined architecture on which language as DDL, DML, DCL can be performed.

7) Describe HEAP Table in MySQL.

HEAP is a memory structure used to store high speed temporary storage.

8) What are the set operators used in MySQL.

  • UNION and UNION ALL
  • INTERSECT
  • MINUS

9) Describe MySQL Constraint in MySQL.

NOT NULL CONSTRAINT: It defines the value stored cannot be null for a particular column in the table of a database.

PRIMARY KEY CONSTRAINT: When a primary key is generated for a table then that key is used to describe any relation is defined as primary key constraint.

FOREIGN KEY CONSTRAINT: It allows foreign keys to let you cross-reference related data across tables, which help keep this spread-out data consistent.

10) Enlist the drivers required for MySQL?

  • PHP Driver
  • JDBC Driver
  • ODBC Driver
  • C WRAPPER
  • PYTHON Driver
  • PERL Driver
  • RUBY Driver
  • CAP11PHP Driver
  • Ado.net5.mxj

11) What is MySQL globalization?

  • MySQL characterset
  • MySQL collation

12) Differentiate between DROP and TRUNCATE ?

DROP: Completely Delete DATA as well as STRUCTURE from the table whereas

TRUNCATE: It Delete the DATA but PRESERVES the structure.

13) Enlist the type of Join in MySQL.

14) Enlist the type of Trigger possible in MySQL.

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

15) What is BLOB and TEXT in My SQL?

BLOB (Binary Large Object): It stores variable amount of data and is of 4 types.

TEXT: It is a case insensitive BLOB having non-binary string (character string). It is of 4 types.

16) What is the storage engine for MySQL?

Storage tables are named as table types. The data is stored in the files using multiple techniques such as indexing, locking levels, capabilities and functions.

17) What is the difference between primary key and candidate key?

Primary key in MySQL is use to identify every row of a table in unique manner. For one table there is only one primary key. The candidate keys is used to reference the foreign keys.

18) What is the use of ENUM in MySQL?

ENUM in MySQL will limit the values that can go into a table. For instance; the user can create a table giving specific month values and other month values would not enter into the table.

19) How to resolve the problem of data disk that is full?

When the data disk is full and overloaded the way out is to create the soft link and move the .frm as well as the .idb files into that link location.

20) What are the storage models of OLAP?

The storage models in OLAP are:

21) Explain transaction in MySQL?

Transaction is logical unit of work where either all or none of the steps should be performed.

22) What is Drool?

Drool is the BRMS (Business Rule Management Systems) that has forward and backward chaining inference based rule engine. There are 2 major components of drool are:

  1. Authoring:This process comprises of the formation of Rules files which is .DRL files.
  2. RuntimeThis process comprises of the formation of occupied memory and handling the initiation.

23) What is JBoss Enterprise BRMS?

JBoss Enterprise BRMS is the reasoning engine for policy and rule developments for business. It also manages access and changes.

24) What are federated tables?

Federated tables allow access to the tables located on other databases on other servers.

25) What is ISAM?

ISAM (Indexed Sequential Access Method) was developed by IBM to store and retrieve data on secondary storage systems like tapes.

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