what is primary key,unique key, foreign key? can u teach me
in simple language?
Answer Posted / uma maheswari
primary key:
IT IS THE MAIN KEY AND IT DOES NOT ALLOWS THE NULL VALUE...
Unique key:
IT IS SIMILAR TO PRIMARY KEY .IT ALSO DONT ALLOWS THE NULL VALUE.
foreign key:
IT IS USED TO REPRESENT THE PRIMARY KEY VALUE...
| Is This Answer Correct ? | 1 Yes | 1 No |
Post New Answer View All Answers
what is ad-hoc access? what is the diff b/w managed query and ad-hoc access?
What is the difference between primary key, foreign key and candidate key?
What is the use of graph database?
Please post the scenerois for writing the complex sql queries , for my practice.Can be any query if you cannot solve.
What are the advantages of normalizing a database.
If the master device is full, how do I make the master database bigger?
What are the advantages of using database?
How much does it cost to build a database?
How many types of locks are present in a database?
Differentiate between extension & intension?
What are different types of clusters present?
aht is the difference b/w network & hierarchial & relational dbms????
What is a database example?
What is the purpose of TNS?
What is the concept of Virtual field?