Answer Posted / saraswathi muthuraman

Compost key :

More than one column will be used to create compst key

SQL> create table ts_250 (a number,b number,c number,
primary key(a,c));

Table created.

here column A and column C is used to create compst key.
U can't insert null value in both columns.
Only unique combination of column A and column B value can
be inserted.

Primary key :

Key will be created on a single column in table.

SQL> create table ts_251 (a number,b number,c number,
primary key(a));

Table created.


null value cann't be inserted into column a.
oracle will create a index
only unique value can be inserted into column a.
only one primary key can be created on a table

How to create a new view in mysql?

540

---

Is mariadb faster than mysql?

469

---

How to display odd rows in student table in mysql?

473

---

How to enter microseconds in sql statements?

525

---

How do I rename a table in mysql workbench?

503

---

---

Can't connect mysql server on localhost?

507

---

Is mysql is a programming language?

529

---

Write a query to fetch duplicate records from a table using mysql?

507

---

How can you filter the duplicate data while retrieving records from the table?

478

---

How to return query output in xml format?

598

---

What is truncate in mysql?

430

---

What is general log in mysql?

464

---

What is schema in mysql?

500

---

How to use triggers to track changes in mysql?

487

---

How to show all records starting with the letters 'sonia' and the phone number '9876543210'

523

---