MYSQL REVISION TOUR
1. What do you mean by a Database Management System?
Ans- Database Management is a collection of programs and files that allow a user to define structure of a database, store data into it, modify the structure and manipulate the data.
2. What do you mean by Relational database?
Ans-Relational Database is a type of database in which relation is used as its basic element.Row and columns are used to store data.
3. What is a foreign key?
Ans If a key is available in a table as a primary key then this key is called foreign key in another table.
4. What is primary key?
Ans-Primary key is a unique key in a relation which can uniquely identifies a tuple (row) in a given relation.
5. What is SQL?
Ans-SQL is stands for structured query language. This language is used to manipulate data stored in a table.
6. What is referential integrity?
Ans-This is a rule which ensures that in DBMS relationships between records in related tables are valid. And that user don’t accidently delete or change related data.
7. What is MySql?
Ans-Mysql is an open source RDBMS which uses SQL.
8. What is DDL?
Ans- DDL provides commands to define or redefine the schema of a table.Table is created,altered and dropped using DDL.
9. What are DML commands?
Ans- DML commands are used to manipulate data stored in a table.Insertion, deletion and modifications are possible using DML commands.
10. Maximum how many characters can be stored in a (i) text literals (ii) numeric literal
Ans-(i) Text literals can have 4000 bytes (ii) A numeric literals can store 53 digits.
11. What is null value in MySql?
Ans-If a column in a row has no value, then column is said to be null.
12. Which keyword eliminates redundant data in from a query result?
13. How would you display system date as the result of a query?
14. What is NOW() function in MySql?
Ans- It returns the current date and time.
15. What is NOT NULL constraint?
Ans- NOT NULL constraints impose a condition that value of a row cannot be left blank.
16. What is error in following statement? UPDATE EMPL;
Ans- WHERE clause is missing in given query.
Please refer to attached file for CBSE Class 12 Informatics Practices MYSQL Revision Tour Assignment
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