SQL Interview Questions
Calibrage Info System is a product based Software company since it is from 2014 Feb, through technologies and to build a reputation of being one the of most innovative IT Solution and Service Provider. Nowadays all Organizations are using the database for storing their data for security purpose also.
SQL stands for structured Query Language is a domain specific programming for managing the data in DBMS(Database Management System).SQL Programming skills are the most important and useful. SQL programming skills are highly desirable and required in the market, as there is a massive use of Database Management Systems (DBMS) in almost every software application.
Here are the some of the SQL Interview Questions:
1.What is SQL?
Basically, SQL stands for Structured query language, and it is used to communicate with the database and it is used to perform tasks such as deletion, updation, retrieval and reading of data from the database.
2.What is DBMS?
A DBMS(Database Management System) is a program that controls Creation, Maintenance and the use of a database. It is termed as a file Manager that manages data in a database rather than saving it in file systems.
3.What is RDBMS?
RDBMS stands for Relational Database Management System. RDBMS store the data into the collection of tables, which is related by common fields between the columns of the table. It also provides relational operators to manipulate the data stored into the tables.
Example: SQL Server.
4.What is Database?
Database is nothing but an organized form of data for easy access, storing, retrieval and managing of data. This is also known as structured form of data which can be accessed in many ways.
Example: School Management Database, Bank Management Database, Hospital Management System, Company Management Database.
5.What are Tables & Fields?
Basically a table it is a set of data that are Contained in a model with Columns and Rows. Columns can be categorized as vertical, and Rows can be categorized as horizontal. A table has specified number of column called fields but can have any number of rows which is called record.
Example:.
Table: Customer.
Field: Cust ID, Cust Name, Location.
Data: 234567, Dravid, 09/12/1976.
6.What is a Constraint?
Constraint can be used to specify the limit on the data type of table. Constraint can be specified while creating or altering the table statement. Sample of constraint are.
- NOT NULL.
- CHECK.
- DEFAULT.
- UNIQUE.
- PRIMARY KEY.
- FOREIGN KEY.
7.What is Primary Key ?
A primary key is a combination of fields which uniquely specify a row. This is a special kind of unique key, and it has implicit NOT NULL constraint. It means, Primary key values cannot be NULL.
8.What is Foreign Key Constraint?
A foreign key is one table which can be related to the primary key of another table. Relationship needs to be created between two tables by referencing foreign key with the primary key of another table.
9.What is a Join?
This is a keyword used to query data from more tables based on the relationship between the fields of the tables. Keys play a major role when JOINs are used.
10.What are the types of Joins?
There mainly 5 types of joins are there in the database they are as follows:
1.Self Join,
2.Equii Join,
3.Non-Equii Join.
Conclusion:
Finally ,these all are some the questions comes in SQL for an interview based and also some of the other questions like Types of SQL Language Commands, Normalization, Function, Stored Procedures, Indexes, Views, Subquery.
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